Problem with the combustion leak test
 

I rented the combustion leak tester kit from Autozone and got some blue fluid there to test for combustion leak in coolant, which would indicate a blown head gasket as I've got an 89.

With the car cold, I pulled the pressure relief valve on the radiator cap, and noticed a couple of burps in the overflow tank. Don't know if that means anything. I haven't driven it for a week or so.

So, I removed the radiator cap and siphoned out a third or so of the coolant out the radiator. I started the car and let it warm up with the radiator cap off. I was doing other stuff while the engine was running. At some time after the engine came to temp, I noticed coolant was squirting out the radiator cap opening. I put the cap on while the engine was still running.

After a few minutes, I took the cap off and no coolant was squirting. A few minutes later or so, coolant started squirting out the radiator cap opening, so at that point, I shut the car off.

So, is that normal, or does that mean something is wrong?

I did the combustion leak test on my Firebird a week before with no problems, but I did it differently. I let the engine come to temp, then I opened the radiator cap and siphoned out some of the coolant. Then I did the combustion check.

Bump.

Sounds like the engine block is low and when the thermostat opens, it sucks in water and drains the radiator. But by then the water in the block is heated up past boiling and when the cold radiator water hits the hot water in the block, it all boils out.

I would say the thermostat is either barely opening or not opening. Install a new thermostat and see if it starts acting right.

If you are worried about head gaskets have you ran a compression test yet? You should be around 120-130psi if stock.

If I start my corvette and let it come to temperture, it will shot coolant out the filler hole until I rev the rpms up to 2000 or so , what you have sounds normal...WW

I had someone do a compression test, and it was all good. I will have to get the numbers and post them, I don't know where they are at right now.

Ok, thanks. I did replace the thermostat around 3 months ago, and it has been parked most of the time. I have driven it maybe 3 times since I replaced the thermostat. I put in a stant, I think it was the expensive one failsafe or something. Though, I did replace the thermostat a year ago as well, as when I got it, it ran cold. Like 150 degrees all the time. I think the thermostat was barely stuck open if I remember right. I'm thinking that may be why my spark plugs were carbon fouled, the car probably wasn't going into closed loop running so cold. Don't know how long that had been going on.

What brand thermostat should I get? I'll replace it when I pull the throttle body to clean it.

For some reason, I had no problems with my Firebird. I let it get to temp, pulled the radiator cap opening, siphone some coolant out and did the combustion leak test. It was fine.

How are you supposed to do the combustion leak test if coolant keeps squirting out? I know they say combustion going into the coolant can cause excessive pressure in the coolant system.

I have been told on a cold engine to start it, and feel the upper radiator hose. If it is stiff, then that mean combustion is getting in the coolant system??

I have also been told to get a coolant pressure tester. Put it on the radiator, start the engine and rev it up. If the needle pegs, then combustion is getting in the coolant system. How does this test sound?

Ok, good compression. No white smoke, just the usual blue on start up. No coolant loss. No overheating. No apparent coolant in the oil. Though, I do have crud in the coolant system. All my spark plugs appear to be carbon fouled, I would have figured a couple of them would be clean if there was a leak.

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With the engine idling and the cap off, at some point coolant will begin to spew out, back-flow; that's normal.

You didn't say (or I missed it somehow), what it is you're trying to do.

Are you experiencing a coolant issue? White smoke out of the muffler indicates coolant getting into the combustion chamber.

Black smoke out of the muffler is an indication of a too rich air/fuel mixture.

Blue smoke out of the muffler is usually a sign oil getting into the combustion chamber.

Each has a different cause.

If you're experiencing a blue smoke out of the exhaust and probably using more oil than normal, my first thought is failed valve stem seal(s). This is a common occurrence and installing new ones isn't to hard to do. Just set aside an afternoon.

If you're losing coolant and there's no sign of an external leak - puddles on the floor or in the engine compartment - it's probably a intake or head gasket leak problem.

To diagnose that, you need to borrow a coolant system PRESSURE tester. Screw it on where the cap goes, pump up the coolant system (engine off) to no more than 20 psi and see if the pressure holds. If it doesn't, I put my money on a leaking gasket.

It would help a lot if you explained what's going on with the engine that caused you to begin diagnostics.

Jake

West Point ROCKS!

What I was trying to do is a combustion leak test. I can't do the test if coolant is squirting out the radiator.

The reason why I was doing diagnostics is cause I have an 89 Vette. At some point, you will get a head gasket leak, I figured it would be a good idea to see if they are leaking. Reason cause is I plan on replacing the valve cover gaskets, that will be alot of work. So, if the head gaskets are leaking, I might as well replace those since the rest will be torn apart.

I have no white smoke.
No apparant coolant in the oil.
No apparant coolant loss.
It runs fine.
No sign of coolant leak via spark plugs.
Good compression.

When I did the combustion leak test on the Firebird, coolant wasn't squirting out the radiator.

On the Vette, I did notice while running, the upper radiator hose was rock hard. You couldn't even squeeze it a little.

I think what I will do is put a coolant pressure tester on the radiator, start the car and let it get to temp. Then check to see what coolant psi I'm getting. I'll also do some revs and have someone watch to see if the psi climbs when I rev. If I'm getting high coolant psi readings, then that would tell me extra pressure is getting in the coolant system. Which would indicate a head gasket or head problem.

as the coolant gets hotter though pressure will increase. if its losing exhaust gases into the radiator simply pressurizing the cooling sytem will tell you if its leaking. I just did my head gaskets and it can now hold 16psi indefinitely.

my 90 upper hose got very hard like yours when its thermostat was stuck. easy way to tell if thats the problem is run the engine and if the radiator is cool yet everything else is hot, then must be thermostat not opening much like what mine did. if the upper hose gets soft after awhile of being shut off then its leaking pressure somewhere.

I found out why the upper hose was hard. It is cause it has a spring in it. When it was cold, I checked the hose and it was hard and felt like something was in it. I pulled the hose and found a spring inside.

Though, the bottom hose doesn't have a spring. So, when I flush out the coolant, I may replace the bottom hose with one from the dealer, as I believe those have a spring inside. It looks like I'll have to remove the idler pully to get to the clamp at the water pump.

I'll pressure test the coolant system this weekend if it isn't raining. And I'll start the car with the guage on the radiator to see if I get any excessive pressure readings.

And I'll probably replace the thermostat again anyways. Probably put in a 195 Robertshaw.

Josh, the R&Ring valve covers are just the tip of the iceburg compared to head gaskets. Doesn't look like you have a head gasket problem anyway. VC gaskets are not that bad to do. I would be finding out why the plugs are black. Wild guess would be O2 sensor.:cheers:

Cylinders are numbered 2 4 6 8 on the right; 1 3 5 7 on the left. Your plugs show that at least 2 cylinders are lean - the rest look to be rich - particularly #6 as identified by your photo. My guess is that you have a lean condition or something after the MAF and when that air hits the O2, it causes the ECM to fatten up the mix. A scan would confirm this. Lean conditions are caused by vacuum, intake and exhaust leaks; plugged injectors, or water/coolant in the combustion chamber (and it doesn't take much) or a partially open EGR valve. Your radiator looks clean. Checking your coolant for exhaust contamination doesn't take a hot engine or an engine that's even running so I don't know what or how the kit you bought works. A pressure test should be performed on a cold engine - just pump it up and see if it holds. Doing it on a hot engine is tough because even with a small leak, it could still be above atmospheric and when you open it up, you'll get a geyser. Better to check compression hot and cold - just loosen the plugs a 1/4 turn after the cold test so they're easy to take out for the hot test. You might also check vacuum - you want a steady needle.

You don't have a problem. You're chasing one that you think you have. You said, no white smoke in the exhaust, no water in the oil, the car runs fine. Your plugs are fine too, they're normal looking.

Get a new radiator cap. Problem solved. Drive and enjoy your car.

Listen to him :rofl: :rofl: :rofl: Doing the head gaskets is a pain in the butt!!!!! But if you have the ambition I say go for it, especially if it has higher miles. Be smart if you do the head gaskets and have the heads surfaced by a professional and not someone with one of those belt sanding machines.

I wouldn't run the motor with a pressure tester on the car !!!!!! because when you take the system to 16psi and then the coolant warms up it will naturally gain more pressure. When I tested my cooling system just the hot sun caused my sytem to increase the pressure a bit without the motor running , so imagine what the running engine will cause it to do ..... Without the radiator cap on it can build high pressures potentially rupturing the plastic radiator etc. etc.

I would think if indeed you were forcing engine compression into the cooling system and the cooling system was exceeding 16psi constantly, you would hear the radiator cap releasing it through the overflow bottle. I'm pretty sure it would be making a gurgling sound a lot.

A sure sign is like everyone says loss of coolant all the time .... if you have coolant going in on the drivers side, you can be sure you will see the o2 sensor rusty looking (mine was) But no matter what you will see white smoke out the pipes but sometimes it's not always real noticeable, after the motor is shutdown it may lock up when you try to start it, of course water in the oil.

good luck

Would the rust be on tip of the O2 sensor? I was planning on replacing that, so I'll look at it when I do.

And I plan on draining and flushing the coolant. I have an oil cooler on mine. Could I pop the oil cooler line off to drain the block? I can get to those hoses unlike the drain plugs and/or knock sensor. I just need to get the tool to remove the oil cooler clamps. Or would the oil cooler hoses not drain the block?

If you look at the routing of the oil cooler hoses, they just go from a t-fitting near the water pump to the cooler and back. One is on one of the heater lines. The cooler itself doesn't get any coolant directly from the block. To drain the block, you will need to remove knock sensors.

As far as the hoses themselves, I don't think that they are available anymore and they are molded hoses. If the end splits while you are removing it, you will be looking for a replacement. there is an AC Delco catalog that shows all sorts of molded heater hoses and it's possible that you could find a similar one.

It would actually be a good idea to replace all of the coolant hoses if you are going to do a flush but again, finding all of the molded hoses for the car could be problematic. But looking at the pic of the radiator and the coolant traces, the coolant looks clear so maybe just removing the lower hose and draining the radiator will be enough. Then next year, drain only the radiator.

If your existing lower hose doesn't have an internal speing, chances are it's a generic parts store replacement. The spring is needed to prevent the lower hose from collapsing.

FWIW, I can let my 87 idle with the pressure cap off for almost any amount of time with the cap removed once it hits operating temp. From your overflowing description, it sounds like you have (or had) a stuck thermostat. If anything, when the thermostat opens the coolant level in the radiator should drop quickly.

There is some crud in the radiator. I have probably drained and refilled the coolant in the radiator 3-4 times already within the last year.

Today, I had the engine running from a cold startup and pulled the cap on and off every so often. The level did drop some and I filled it up with distilled water every so often when the level dropped. When I did filled it up, and some of the coolant comes out, I did notice some little specs every so often. Probably rust and some other crud that you can see on the radiator fins. I'm hoping that is just those pellets from the dealer, as the color of the crud is the same. I'm getting a flexible pressure washer wand to put on my garden hose. I'm gonna flush the inside of the radiator out, and hope that removes most of the crud. Probably would be best to remove it, but I'll try it in the car with the lower radiator hose removed first.

When I got it a few years ago, I think the thermostat was stuck open if I remember right. I noticed the temp stayed at 150* while driving around all the time. I replaced the thermostat, and I think it might have been barely stuck open. I did replace it again a few months ago with a 195.

Anyways, today after the temp got to 180*, I felt the upper hose and it was a little warm. So, the thermostat must have started to crack open sometime shortly after 180*. I could tell coolant was flowing at 190* or so by feeling the upper hose.

During this time, I was pulling the cap on and off checking the level with no problems. I did turn the heat on, and the coolant dropped more. I turned the heat off, and topped the radiator off. This was passed the 200* mark and no coolant coming out. Though, I did notice some small bubbles in the coolant one time I pulled the cap after it hit the 200* mark. Could the bubbles just be air in the system? I know when the engine was running last time and I had the cap off, I lost over a gallon of coolant. So, I say some air got in the system when that happened.

Well, the temp crepped up to 222*, and at that time the radiator cap was hot. I barely turned it, and hot coolant started coming out. I turned the cap to close it and turned the car off.

I lifted the red lever on the cap to relieve the pressure as I was getting a low coolant light again and the coolant filled up the overflow bucket. When cold, the level in the overflow was at the cold mark.

So, it looks like the coolant comming out of the radiator is happening at the 210-220 mark. I know I had the cap off at 200* and no coolant comming out.

Ok, I had the Firebird and let it idle to temp at 220*. I pulled the release valve on the radiator cap, and just a couple of burps went in the overflow bucket. I took the cap off, and there was no coolant flying out. The coolant level was an inch or so low, but I say that was what flowed out when I released the pressure.

So, something must be wrong with the Vette. As when I did the same thing to the Vette, the overflow bucket filled all the way to the top when I released the pressure at the radiator cap. The level was at the cold line when cold.

And with all that pressure and coolant released, when I tried to take the cap off, coolant started coming out. Tommorrow, I'm gonna start the car with the cap off and let the thermostat open. Then I'll watch and see how well the coolant is flowing through the fin tubes. I'll probably rev it a few times when I start it and with the cap off. I was told if you do this and coolant flies out, then it is the head gaskets.

I got a coolant pressure tester from Advance Auto Parts, but none of the adapters fit the radiator. So, I'm gonna rent one from Autozone.

:iagree:

I don't know if there is a head gasket problem and it doesn't look like a coolant situation, but looking at the plugs there's something up with combustion. The only time you see black on plugs (these days) is because there's too much fuel - either from weak combustion or because it's dumping too much gas. If everything else is ok, oil will burn away, but crust up the plugs. Seriously doubt you'd see perfect BLM's on this car, but I've been surprised before.

Water boils at 212F at sea level. A 50/50 mix of anti-freeze and water raises that boiling point to somewhere above 250-265F or so.

Now, if you've been adding only water to re-fill after the over-flow incidents, it's possible you've diluted the mixture to where the boiling point has been considerably lowered. There's an inexpensive tester made by Prestone that can tell you what water temperature protection you have.

You could have air in the system. For an 89, the best was to get the air out is to use the packing method.

Here's how do it: I idle the engine until the temp rises to a point that the stat is open.

While it's idling I prepare a jug of 50/50 mix and place it near the radiator cap opening for easy access.

Once that's done, I reach over and bring the RPMs up to 2000/2500 or so and while holding that RPM, I slowly remove the radiator cap. Once the cap is off, the coolant level in the radiator will be low; you may not even be able to see it.

I then pour in enough of the 50/50 mix to bring the coolant level up to the bottom of the neck of the radiator and while still holding 2000 RPMs, I replace the cap and fully tighten it.

Only then do I let the RPMs return to idle.

Here are the things that I'd consider as indicating a problem:

Coolant in your oil or

White smoke out of the muffler or

A coolant puddle under the car or

Fans not coming on or

No sign of coolant flow in the radiator or

Airflow to the radiator being blocked by debris.

Off the top of my head, I suspect your fouled plugs can be traced to a bad 02 sensor. I'll bet that if you check you'll find that your system is staying in Open Loop. It can be checked with a paper clip inserted in the ALDL and watch how fast the SES light flashes.

Hope some of this helps.

Jake

West Point ROCKS!

You can buy the oil cooler hoses from the dealer, should be about $10.00 each. If it were me, I would remove the radiator and clean it out, and replace all of the hoses. Fouled plugs could be lots of things, see if you can take the car somewhere and have it scanned.
BTW, your car is '89? Have you ever changed the injectors?

one of my plugs looked like his 2 odd colored ones when I had a blown head gasket ..... pull you o2 sensor if any coolant is getting in there you will be able to tell. Or do this pull all 8 plugs pressurize system then yurn motor over and see if any coolant comes out. You will only see coolant in the oil if a lot of coolant is being put into the cylinders.

smell your exhaust when it running, you can smell the antifreeze if theres a problem.

mine always had a trickle of bubbles in the radiator cap area

Even though I had it changed annually (and I never noticed a coolant loss), mine had crappy looking coolant, noted by the Dealer during the warranty, but that's as far as they ever went with it.

My heater core was plugged up somewhere around 40,000 miles.

My aux fan was coming on - when it was new it never reached the threshold for it to come on.

The #7 plug was cleaner than the rest and there was rust on the threads (within a couple hundred of miles when I finally got serious about trying to figure out whether there was something wrong with it).

Compression tests were normal.

My idle wasn't perfect, but it wasn't any worse than I had experienced in any other fuel injected car that I owned.

After it finally let loose and teardown, I could readily see that it had probably been a longstanding issue.

I found this Forum looking for others with similar!

Yeah, I noticed the plugs were carbon fouled. I think that probably was from when I first got it, I noticed driving around it stayed at 150*. I pulled the thermostat and replaced it, and the temps went up to 200 range. No telling how long that went on for.

What is the part of the plug you look at when you look for a coolant leak? The curved piece of metal? Or the white ceramic part?

Yeah, I think I'm gonna remove the radiator, and flush it real good. I've got on order a flexible water blaster. www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96541

The PO replaced the injectors and fuel regulator. He put in Accell injectors.

Do you guys use any chemical flushes for the system? And I was wanting to remove the knock sensor so I can drain the block out and flush it real good sense there is stuff in the coolant. Could I jack up the car to remove the knock sensor? The PO gave me a brand new knock sensor with the car. I took it to a shop to replace it and drain/refill the coolant a while back. I brought in enough coolant to refill the entire system. When I picked it up, I noticed they didn't use alot of coolant. So, I figured the knock sensor hole was probably clogged.

I'll pull the O2 sensor tommorrow. What do I look for? Rust on the tip? And how are you turning the motor over? I don't know how to do that.

I put a pressure tester on the radiator today. I pumped it up to 16 psi, and watched it for 10 minutes. The car was cold. It held 16 psi for the 10 minutes I was watching it. Though, for some reason when I relieved the pressure from the tester, coolant poured out the cap area.

Just wondering. But before I did the test, I pulled the relief valve on the cap, and got a couple of burps in the overflow bucket. I haven't started the car in a week. Is this normal? I've noticed this before.

If you're getting coolant in the combustion chamber your plugs should be steam cleaned, white. Little or no color to ant of the cylinder(s) experiencing the leak.

Your plug color is on the opposite end of the spectrum, telling me you most likely have an injector(s)/fuel regulator leaking and/or your engine isn't going into Closed Loop caused by a bas 02 sensor.

A good firing plug will have a light tan or grey color and a thin darker ring on the ceramic/porcelain or whatever it's made out of. When reading plugs for the correct A/F ratio, the position of that ring (how deep in is in the shell) is what to look for. To see it well, you'll usually need a lighted magnifing glass though.

Plugs as dark as yours means something very different in going on. If it's oil then it could be valve stem seals or rings.

First check to see if you ECM had any stored code. Then get a digital voltage/ohm meter and start checking your sensors - TPS, MAF, 02, knock, coolant temp, fuel pressure regulator, ignition timing.

Time to buy a Factory Service Manual and follow the trouble-shooting procedures in it.

We can only advise you what to do, we can't make you do it. Horse to water adage.

Jake

West Point ROCKS!

When I bought it, the PO told me that he had a miss problem and replaced the injectors. And that it turned out to be the fuel regulator. So, he had that replaced too.

He also gave me a brand new set of spark plugs. Split fire I believe. So, I'm assumming he had plans to replace the spark plugs after he put in new injectors and the fuel regulator, but never did.

Those are the spark plugs that were in it when I bought it. So, I'm assuming the rich problem was from the faulty fuel regulator. And it probably wasn't going into closed loop as the temp would just get to 150* driving around. Replaced the thermostat, and the temps went up to the 200 mark or so.

Though, I'll go ahead and replace the O2 sensor, as with the previous rich problem, it is probably bad anyways. Is the Bosch O2 sensor good, or go to the dealer, AC/Delco? I already put in a new knock sensor, as the PO gave me that too.

I know the PO replaced the cat. And I don't know if 89's had precats or not, but if it did, then the PO had them removed. I later noticed there were some holes in the exhaust right after the bend at the mufflers. The pipes are rusty. I was able to brake one of the mufflers off at the rusted through spot. I had the rusted through parts of the exhaust cut out, and had the mufflers re-attached with new pipes. I didn't do a cat back, but probably should have. I know I shook out lots of crap out of the muffler.

If your injectors are the Accel Yellow Tops, they could be your problem. Also, what size are they?

85-93 Accel fuel injectors. 24lbs/hr. 150824

When I got the fuel injectors box, I pulled the two boxes of spark plugs the PO gave me. They were in an Accell spark plug box. I never looked in the box, I assumed they were new spark plugs.

But I looked at the spark plugs, and they were AC/Delco. Probably the ones from the factory. They were carbon fouled. So, the the fouling was happening before the PO replaced the injectors and fuel regulator.

I'm thinking it was cause the car didn't get up to temp when I got it, so it ran rich. I got that fixed a year ago. I'm gonna replace the O2 sensor.

I put in AC/Delco standard plugs in 3 months ago. I've only driven it 3-4 times since. I'll probably pull a plug just to see if it shows any signs of carbon fouling. I did notice the other day that the Delco plugs I put in have rust on the part you put your socket on. I don't know if that is normal.

Those are the same injectors I have in my car, and it runs great. They are not your problem.

The rust is normal.

I don't drive it much. But I will probably check the plugs once a month or so to see if they do start carbon fouling.

I'm gonna remove the radiator and flush all the crud out. Then flush the heater core. Then I plan on draining the block and flushing the crap out through the block drains. Then I'll put in a new thermostat and see if I still have the same problem.

If you have a "fail safe" stat, it is possible for it to get stuck all the way open if you have air and/or excessive pressure. There are 2 little clips that catch the valve when it opens up too far. This happened to me when I "packed" the radiator as described, which I have always done since I bought my vette in '95 and had serious overheating problems. The fail safe was a recent installation. My overheating problems were finally cured back in the day when I removed my radiator and pressure washed the fins from the outside. Tons of little grains of sand came out, which were practically invisible when looking at it. After my "fail safe" was unstuck with a screwdriver, I drilled two 1/8" holes in it to take care of any air bubbles that might blow the thing stuck open again. I also have left my rad "unpacked" at this point. My car is running right at 190 degrees which is where I like it. I highly doubt you have a gasket problem.

I did put in a fail safe thermostat. It was the most expensive Stant thermostat.

What brand thermostat are you using? I was thinking of putting in a 195 Robertshaw. They are supposed to be better flowing, and resist pressure from the other side which can cause the thermostat to close. And it is supposed to let the air bubbles pass through compared to a poppet type thermostat.

I'm gonna power flush the outside and inside of the radiator.

I believe mine is a Stant also....got it at the "zone". I had no idea that it would stick all the way open like that until I had to take it out when my car would not get over 130 degrees. Like I said, it happened right after I packed the radiator in the fall before I put it away for the winter.

Just curious. But with the engine cold, if you pull the pressure relief valve on the radiator cap, do you get any burps?

Mine does this. I pulled the valve on a cold engine, and got some burps. A week later I went out and pulled the valve on the same cold engine as I didn't start it any, and got some burps.

I believe that is a good thing Josh. There should actually be a vacuum as the coolant cools off, drawing water from your overflow tank back into the radiator. I would be worried if nothing happened when you pop the cork.

the sun alone will cause pressure to build in the cooling system. Not much but enough to burp a little coolant out if you release the cap. here is my 90 after a head gasket change. notice the pressure dropped and two hours later it rose. If you lost all pressure after sitting then yes I'de be worried. thermostat housings are always a source of pressure loss as are loose hose clamps even the seals for the radiators plastic tanks.

anyways here is a 2 hour pressure test on my 1990. the second picture was a result of a loose hose clamp, after tightening and sitting notice the pressure just from sunlight made it rise again.

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I did my pressure test on a cold engine for 10 minutes. Was that long enough?

I did notice that if I set the unit down on the tire, that the needle would drop just a little. So, I had to pump the pressure back up to 16 and hold it in my hand for 10 minutes.

Josh...if your car doesn't overheat, I would say you cooling system is up to snuff and you have no gasket problems. The water coming out of the radiator is normal with the cap off, as you are lowering the boiling point by de-pressurizing the radiator. gurgtles and farts in the system is completely normal, hot or cold.

Ok, thanks. I just thought it was odd how my Firebird didn't do this.

I still have some blue fluid left. So, I'll probably use it to test it instead of letting it go to waste. If exhaust was getting into the coolant, when could I test it with the combustion leak tester? Right after I start the car up, or wait till the thermostat opens up? Cause if I have to do it after the thermostat opens up, then I'll have a short window to do the test before coolant starts comming out.

The sun doesn't cause the water pressure to rise in an engine. More like the thermostat in the gauge is getting hotter in the sun would cause the needle to move slightly.

Once an engine is up to operating temperature or any temperature and shut off the temperature does rise a few degrees. Why, because there's no water circulating through the radiator and engine. No more fan to cool the water or antifreeze mix down.

Pressure that builds in the system comes down when the engine is shut off. When the water or antifreeze cool to the outside air temps the pressure is releived in the system.

Now, as I said days ago, buy a 5 dollar radiator cap and that's that. You're chasing a ghost that isn't there. Oh, do not use a pressure washer outside or inside your radiator, you'll blow the thing apart and then you will have leaks, you'll be buying another radiator.

:iagree:
Just take the car for a drive and enjoy it! Remember if it ain't broke don't fix it. Take it out and hammer it a little it will run better, and you will feel better for doing it. Remember to WAVE :cheers:

either it's gonna go or it's gonna blow ..... have fun

In the first post you said Autozone had a blue liquid to test for CO gases in the coolant. I've asked around at various places and they never said they had that; what is it called? Maybe I just wasn't asking them the right thing.

I think it is a block test. They have a picture of the fluid and the tester on one of their mats that sits on the counter.

Ok thanks. Yeah, the radiator cap I replaced that 3 months ago, so that should be fine.

I was finally able to do the test. I let the car warm up while I was playing around with the HVAC programmer. So, the heat/ac was on while it warmed up. When it got to 190-195, I took the radiator cap off and siphoned out 1/3 of the coolant in the radiator.

I began to do the test, which was squeezing a ball sucking the fumes from the radiator into a tube that had blue liquid in it. After about a minute of doing the test, I went to check the temp and it was holding at 198-200. I did the test for a few more minutes and checked the temp, it was holding at 198-200.

So, I turned the heat/ac off, and kept doing the test, and a few minutes later I checked the temp and it was 207, so I turned the heat back on as last time when the temp got to 210+ coolant started coming out.

Anyways, I did the test for around 10 minutes just to be sure. The fluid stayed blue, so that is good. With the heat/AC on and idling, it looks like my coolant system is doing fine. But I'm still gonna pull the radiator and clean it. And pull the drain plugs and rinse the inside of the block with water.

Though, I may still have a rich problem, or spark problem. When I started it cold, it did fine. But the few times I reved it real good in park shortly after starting it cold, I got a couple of back fire pops from the exhaust when the RPM's were high for a split second. Don't know if that is normal or not?

NEVER rev up a cold engine; cardinal rule. Oil/fluid/lube doesn't flow as well when cold and you're just asking for trouble.

It's an old racer's rule; we even warm the differential lube and trans fluid before heading to the water.

Jake

West Point ROCKS!

Ok, thanks.