Fixed!!!: 08/24/08 Finally have fixed the problem. Tried the nano technology which did improve the problem but at 212 deg it would rapidly increase to 260+. So I bought the product called Blue Devil which will probably make an engine rebuild impossible from what I have heard but I was planning on buying a crate engine anyway so I could build a strong performer for the supercharger.

Thanks to all that replied. It must have been a crack or blown gasket somewhere letting gases into the coolant even thought the test show negative.

Thanks again,

Lon


Sorry for the long post but I want to give as much info up front as possible.

I have a 1988 with the procharger conversion, running stock timing, with ported heads, SLP intake and stock ported plenum. The old radiator blew apart after replacing a faulty thermostat but never reached 240 degrees before that. Now I have been chasing a overheating problem for about a month now and actually read all the posts on the subject back to 2006.

Anyway the car runs fine at low speeds going around the block up to 45 mph. It takes alot of hard accelerating to get the car to 200 deg. If I go onto the freeway it gets to 198 or so until I get off then it will drop to around 191 or so.

Here is where it gets weird, once off the freeway I get onto a stretch of road at 45 mph for about a quarter mile if I stop at a light the temp will immediately start climbing 1-2 degrees a second. The light will usually turn green in time for me to start moving when the temp is 245 or so.

But as I start moving (doesn't matter if it is light of heavy acceleration) it will continue to climb. About a mile of so down the road I will turn into my neighborhood and it will drop to 248 then when I pull into the driveway it jump back to 259. Here is what I have done so far.

New Radiator all aluminum 2 core
No thermostat (until this problem is fixed)
New Water Pump
New Upper and Lower radiator hoses
New Radiator Cap (doesn't pop till 250 to overflow)
New coolant temp sensor
Burped system to where no low coolant light comes on
Fans run all the time from start up
Tested for exhaust gases in coolant (none)
No white smoke present
No oil in coolant

Could there still be an air bubble somewhere trapped?

Could the computer be at fault somehow? Running lean or too much advance?

I have the ability to scan the car and record the data in real time from all sensors so if I can provide info from that to help answers let me know.

It seems from all the driving tests I do it is fine as long as I don't hit 212 degrees after which it will climb to a minimum of 248 and not come back down which make me think that the system is bleeding to atmosphere or something.

My next step is to pull the heads but I would like to try to fix this some other way. Once the heads are pulled I would have to rebuild the bottom end (still stock) cause it would be the perfect time to but money is tight and I don't want to rebuild it and continue to have this problem. I learned a long time ago don't change parts outside of the problem area until original problem is fixed or you hurt your chances of diagnoses.

Thanks for any help in advance,

Lon

 

First thing I would do is put a thermostat back in it, it is possible the coolant is moving too fast through the system to be able to transfer its heat to the radiator.

How many PSI are you running? You could be getting some detonation at stock timing (not related to the temps)

Also, if you're not tuned and still on stock injectors then you are going lean for sure, no question about it. You've done lots of mods to add more air into the engine, you need to add fuel as well.

Other than that I would double check the water pump, since it sounds like its more of a problem at low RPM, you also may have gotten a radiator with some blockage or damaged coil etc.

 

The supercharger runs 6psi was done 4 years ago before I bought the car it does have the fuel booster pump and FMU to compensate for boost although I don't like it. So I have new injectors from Jon at FIC and a new computer that will be flash programmable as well as compensate for the boost.

The waterpump moves alot of water at low rpms with the cap off way better than the old stocker it almost wants to shoot out of the neck when I rev it its such a strong flow. As you suggest maybe too strong I will try it with the new thermostat tomorrow. Thanks for the input.

Lon

 

No problem Lon, keep me updated on how it goes. Jon is an awesome guy with an awesome product.

Thats good that there is some kind of fuel enrichment, when you said stock timing I assumed it was untuned so thats good.

You've replaced damn near everything so I don't wanna condemn anything on ya, but if the thermostat dosnt help, I'd try a different rad, since your not running lean (more than likely) and the water pump flows well.

 

Sounds to me like your water pump is cavitating once it gets hot and not moving any water. You need some type of a restriction like a thermostat to keep the pump working properly. To work correctly the WP needs to 'push' the water against something to maintain some degree of head pressure and therfore keep the WP primed properly.

 

Okay put in new thermostat (180 deg) and took car for a spin went about 1 mile at 25-45 mph oil temp was still to low to show a degree and coolant hit 255.

I let it sit for 5 min and started the car again it had cooled to 234 that seems odd for 5 min with no boil over so I went and got a 16psi cap with a thermometer built in. Went for a drive car temp climbed in 2 and 4 deg steps to 264 but cap showed 165 and oil temp showed 204 deg. Could be an air pocket under the cap though. I didn't get a low coolant light till after I shut it off the second time and restarted it. And once again in 5 min it was at 238 down from 264. So I will let it cool down to draw in the reserve and top it off again.

Could this be a faulty ECU the coolant side of the digital dash has been dimming from time to time.

I can put my hand around the lower radiator hose and heater hoses when the temp on the dash was 264 but the upper radiator hose was to hot to hold onto for more than a second (I have real good heat tolerance in my hands). And when I put a thermometer to the hose it read 180 and the surface of the radiator was 200.

Also when the car was 260 deg I carefully removed the overflow hose and it was bone dry no bleed off from the cap.

I'll update again after it cools and I top it off and drive again.


Thanks,

Lon

 

Okay I went outside and checked the temps and they were at 180 in car 120 on cap. Removed the cap and added 1gal of coolant/water. So that was a big air bubble. Then took for a drive and let it get up to 212 and pulled into the garage where it climbed up to 224 before going back down to 215. The temp on the gauge showed 193 compared to 212 in the car but I had a low coolant light intermittently when stopped. Upper hose is a little cooler this time.

This might not be related but for the first time since I have had the car it did not go to 0 psi fuel pressure when shutting off the car. The gauge would never react to throttle and I would have to flick it to get unstuck. But I know I had/have a leaky injector because I always smelled fuel out the air cleaner after shut off. Anyway thats another issue which I will resolve outside this one unless it could have something to do with my problem.


Thanks

Lon

 

Well after a little unfortunate event I now have 1st and 2nd degree burns on my back an right arm. A hose clamp that I was going to replace today popped and the upper hose came off right next to me. I was lucky that I turned away to protect my face and ripped my shirt off fast enough. So after a doctor visit and an appointment with the burn center tomorrow. I refilled the system and heated it up at idle to 240 and am letting it cool. But I just had a thought what if both thermometers are right and the coolant at the cap is lower by 60-70 deg. And by the time it reaches the top of the block at the coolant temp sensor it is way hot. That would explain the lower hose being dramatically cooler while the upper is way hot. Which really points to a blown head gasket or combustion problem right?

Lon

 

I had a similar problem that I fought for several weeks, Albert fought it for 4 year... look at our threads. http://forums.corvetteforum.com/show....php?t=2015572

But, in short, you probably have a small head gasket or similar cooling system leak that is pumping exhaust into the cooling fluid at road rpms.

Albert and I both corrected our problem with a fine nano particle sealant.

On my LT-1 I could have it idle in driveway for two hours in 90 F ambient temps and not overheat, but drive it down the street and it would slowly creep up to 240 then jump to 255+ and start puking into the overflow tank.

Mine started when I sucked a plastic bag off the street onto the radiator and it ran hot.

Check if cooling system will hold a pressure and also hold a vacuum.

 

Wow I just read your post 20 seconds ago. And for some reason this morning while grabbing more parts I bought that exact product.

How many times did you flush your radiator? Did your pull freeze plugs and or the knock sensor to flush?

I have the tee to flush the system but will want to do it right to use this product.


Thanks


Lon

 

Lon, I pulled the two knock sensors per the FSM, but I put in two 1/4 inch NPT nipples and put the 'T' in a clear hose between the two Knock sensors holes. that way I could back flush and also pump water in via the top. I also opened the radiator drain and let water flow with the garden hose for an hour.

When I let the K&W 'dry' I pulled the radiator hoses off to permit more air.

If you can identify which cylinder is leaking, pull that plug and deactivate that injector while you warm with the sealant circulating (no cylinder pressure working against sealant). I never could isolate my leak.

Sorry you got burned !!!!

Albert said he had two dealer try to solve the problem over 4 years, but no success.

I seem to have solved my problem, but if not I will use this nano again. But, use some caustic in the cooling system flush (by-pass aluminum radiator) to etch the metal to get a better surface for the nano particles.

Send me an email with your telephone if i can help more.

let us know your results

Joe

 

Thanks Joe,


I will keep you informed when ready to try. I am willing to bet that I have the same problem as you and like you cannot use tests to identify the small cracks.

Thanks,

Lon

 

Well guys I spent the last few hours researching this product (made by CRC) and have found mixed reviews of it and none that said it worked for more than a year in fact very few testimonials. Most said it worked at least temporarily. The up side is it is definately a diagnostic tool if it works you know you have a leak somewhere . Good luck and keep us updated.

 

The product that Albert and I used is K&W nanotechnology head gasket repair. I tried GM P/N 3634621 sealant per the FSM, it did not work. It seems my leak was so small that the GM sealant would not penetrate. this K&W (maybe others) is fine enough to go into the leak passage way.

The diagnostic tool is BOTH cooling system pressure and system vacuum hold.

Two mechanics on the C-1 forum said they had seen this K&W repair used successfully for over two years. At $20 and a flush vs. $2000 at the shop or many hours under the hood to replace gaskets, I do it every 90 days.

Joe

 

I hear ya it is a lot easier than tearing the engine down. Just giving you a heads up on what I found and I did not find any testimonials that said it worked for 2 years. I was looking at it to fix my heater core ocassional leak if I would have found some more testimonials saying it lasted I longer I would be using it. I am on the fence. The main ingrediants are sodium silicate, Aluminum powder( The nano part) and copper flake and are used by other companies in different mixtures as a sealer as well.

http://www.crcindustries.com/faxdocs/msds/401232.pdf

 

[QUOTE=Redeasysport;1566651066]I was looking at it to fix my heater core ocassional leak if I would have found some more testimonials saying it lasted I longer I would be using it. I am on the fence. The main ingrediants are sodium silicate, Aluminum powder( The nano part) and copper flake and are used by other companies in different mixtures as a sealer as well.

On your heater core, I would try the Bars aluminum particle sealer. I believe your heater is aluminum?, I have used it for 30 years in my 61, to plug MULTIPLE small holes in the aluminum radiator. It will hold pressure for days. Aluminum has a tetrahedron crystalline structure and seems to mechanically attach and hold.

 

Fixed!!! See first post in thread for explanation, happy to have my car running again.

Thanks

Lon