I just fired up my newly rebuilt engine( that I assembled) for first time. I ran it about 20 minutes at 1500-2000 rpms. I didn't put a radiator cap on and it did spew some coolant out when I shut it off. The temp guage reached 200 during the run time, but climbed to 220 when I shut it off. I then noticed that a very small amount of coolant appeared between the head and block below the sparkplugs on both sides. It was not enough to drip but it was wet with coolant. I did use teflon thread sealer on the head bolts and use FelPro headgaskets. I suppose either could be leaking. What do you guys suggest that I do? Since the radiator cap was not on, the system was not under pressure so I'm sure it will only get worse when it is under pressure. Should I reseal the bolts, retorque the heads or what? This really took the wind out of my sails. Thanks, Craig :confused:

 

I'd relax a bit. It sounds like you did all the right stuff.
When rebuilds are "fresh", coolant can just appear from every nook and cranny, I'd let it cool, (which should also dry it up), Fill it with coolant, put the cap on and then watch for leaks. Go from there...

 

I agree with SRAY454. I would check the torque on the head bolts, (I know that the new gaskets dont require this but Im from the old school) fill her up and enjoy the noise...
:cheers:

 

..... OK, drive it, but I'd keep an eye on my engine temperature, oil pressure, and check my dipstick for water every once in while. Is your thermostat OK? I like to re-torque everything after it gets hot too. PM , '74 350 Turbocharged, class of '71.

 

engines are there hotest when you shut them off... they have no coolent or oil flowing through them. So 220 would not be to off the scale.

That would explain the heat flux

:seeya

ZD

 

I have always been told not to run coolant for the first five hundred miles of engine break in.

 

Really? Run straight water? I do not think ethylene glycol is corrosive. The gaskets and sealant are made for that.

What is the reasoning behind that?

 

..... also, if it's just minor seepage, and not related to major problems, a jar of Barr's Stop Leak in your radiator will seal it up. Regards, PM, '74 350 Turbocharged, class of '71

 

First, let me say I feel your "pain". I have had the same experience and it ain't fun. I'd like to ask a couple of questions to help you decide what to do.

Did you have the block or head surfaces refinished or checked for flatness? Could they be bowed or warped? Did you measure them before assembly?

If you had the heads/block re-surfaced did you also have the intake manifold surfaces re-done (required)?

Did you torque the head bolts in the correct sequence and in even steps?

Did you use sealer on the gaskets?

Were there any scratches on either the heads or block surfaces? I've had refinishing shops screwup the finish to a point that the gaskets wouldn't seal.

The only way I wouldn't use gasket sealer is with very perfessionally finished surfaces and careful measurements to ensure a tight fit. The only time I've had good luck at installing heads is by using a slight amount of sealer on both sides of the head gasket, and the bolts.

If you didn't follow the correct torqueing sequence then there is a very good chance the heads won't seal, and you need to take them off and re-do them before you run the engine very far. You can warp the heads if they aren't correctly torqued. If you do decide to remove the heads have them checked for flatness now that they have been on a "leaking" engine and run up to temperature.

Also check the bolt holes for distortion. The "holes" in the block actually pull up with time and can cause the head not to seal tightly with the block. Again, another good reason to re-machine both the block and head of an older engine.

Good luck, but I'd fix the problem and not try to "seal" the holes with stop-leak. Just my opinion.

Andy

 

Andy; The machine shop did not deck the block. He said it was okay. He checked the heads and just dressed them up with a surface belt sander. I did torque the bolts in sequence but according to an engine bulding book lowered the torque because of the teflon sealer on the threads. A mechanic friend suggested that I retorque to a higher #. I did not use sealer on the head gasket because the FelPro gasket info tells you not to use it. I defineitly want to resolve the leak before moving on with my project.
If I remove the heads can I use the same gaskets and can I use sealer on FelPro head gaskets? If so, what kind of sealer should I use? Thanks for the answers. Craig :chevy

 

RE: the "no anti-freeze 500 miles" question... The only reason you might want to do this is because you might suffer a leak, and you don't want to pay for the lost anti-freeze. This is something that could not be done in the northern states in January. Think about it.

RE: Re-surfacing the block... if the machinist checked it for straightness (properly), then it did not need decking. Same for the heads. If it wasn't leaking before the rebuild, chances are it will not (should not) leak after the rebuild as long as you followed the correct torque sequence. In the past 40 years of engine building (professionally) I only came across 1 block (Ford 292) that absolutely needed decking. It had been over-heated, and the crank had broken into two pieces.

RE: Teflon sealer... Teflon sealer originated as a thread LUBRICANT, not a thread sealant (ask any licensed plumber). I don't know why it has recently popped up on this forum as a head bolt thread sealer, but in my opinion, it is not the correct compound to use for sealing head bolts. I would never use it for this application. I suppose you might get lucky using it, but your experience is a case in point why not to use it. Silicone/RTV is also the wrong product. Silicone has good co-hesive properties, but very poor adhesive properties when exposed to oil.

The best product I have found for sealing both head bolts and intake bolts is Permatex #2 non-hardening. There are others, but this one is generally available and reliable when properly applied. The threads (both male & female) must be 100% clean... no oil whatsoever before you start.

RE: Re-using the head gaskets... not adviseable. Get a new set.

RE: Sealer on Perma-Torque head gaskets- also not adviseable, but this also depends on the type of gasket. For example, I use aluminum paint as a sealer on steel shim head gaskets and some old types of composition head gaskets which require re-torqueiong after run-in.

RE: Solution
First try re-torqueing the bolts in proper sequence. If that does not work, remove the heads and start over. This time, chase the block threads with a tap or a thread chaser, run a die over the bolts, clean both with lacquer thinner or Brakleen, coat the tip and threads of the head bolts with Permatex #2, re-install/re-torque to spec. Don't torque 1 time to max.... build up the torque in three steps. Start at about 20, go to mid spec, then go to max. Follow the correct order each time. After you finish, wait about 30 minutes and re-torque to max 1 more time. If it leaks after this, then you have a crack or warped block/heads (not likely). Remember... ANY oil on the threads will blow the whole thing.

I build engines professionally, and this method has given me the best results.... no call-backs.

Keep at it... you will succeed.

 

quite alotta head gaskets say not to use sealer

 

Re:Antifreeze. Also antifreeze will ruin a set of bearings in a hurry if a leak goes internal. From experience. :cry

 

I did torque the bolts in 3 steps and I did chase the threads in the block. I wire brushed the bolt threads and cleaned them well. It sounds like it may be the teflon thread sealer that is the culprit. I even have Permatex #2 in my garage. I wish I had used it on the threads. I am going to retorque and pressure test the system this afternoon. I hope it stops the leak. Thanks for all the advice. Craig

 

The coolant is probably coming up the outer most (short) bolts. Odds are the headgasket is sealing as long as the block & heads are straight and the bolts torqued right.

Here's my recommendation: Drain some coolant to get the level below the head. Take the outermost head bolts out. Clean them off with carb cleaner. Dab some RTV or permatex on the threads, and re-install. Torque to the book torque listing.

 

Zwede; I hope it is that easy, but help me understand. Why would the outer bolts be more likely to leak than the longer ones? They also enter the water jacket, don't they? Craig

 

Antifreeze should not "ruin" bearings any differently than water.


[Modified by Rhys, 9:35 PM 11/3/2001]

 

Do you have an Autozone nearby???
I had a horrible time with my head studs this last winter/ spring.
They will rent you a coolant system pressure tester for about $90.
Once yer done... you return it and get 100% of your rental fee back (unless you break it, of course.)

I've heard, and read that ARP recommends you tighten head bolts or studs, in order, using three steps 'till you reach max torque.
Then, REPEAT the process two more times. So they recommend that you torque down and loosen the bolt three times before you do the final torque.
I had leaking past my threads of my studs, and I went through a set of gaskets before I got the pressure tester. Once I got the tester, it made it easier to check for leakage, and a lot cleaner upon disassembly if you needed too.
I never could get the ARP teflon stuff to work for me... I tried the "aviation brown" goopy stuff from permatex, and it didn't work either.
I finally got the stuff to seal with good ol' hi temp permatex silicone.

About the ARP instruction to torque down and loosen a bolt 3 times before the final set... I didn't do it this way... I went through 3 pairs of Fel-Pro gaskets chasin' down my problem ( I was worried about re-using the gaskets after I had torqued them down) but I finally got it on the third try, with my third kind of sealant. According to others, both the ARP teflon thread sealer, and the high tack brown permatex shouldv'e worked... maybe I just needed to torque and loosen the bolts to pre-stretch them to get them to seal.

When my coolant system could hold 25lbs of pressure for 24 hours... I knew I finally had it nailed down. It was a LOT easier with the pressure testor from Autozone :yesnod: .
Good luck!! :seeya

 

RE: The antifreeze question.. I agree with Rhys... bearings can't tell the difference between water and anti-freeze.
It doesn't hurt to use 100% water on a start up. But I never do, never have in 40 years. My engines don't leak.
And I still maintain that using 100% water in Syracuse in January is a no-no unless you keep the car inside for the first 500 miles.
Everyone in a northern climate would have to keep their newly rebuilt engine in a heated garage for the first 500 miles if the work was done in the winter months.
Sorry... but I just can't go along with that one. In my opinion, it's a waste of time & effort.

Also, I am at a total loss as to why people have so much trouble getting head bolts and/or intake manifold bolts to seal.
I do them once, and walk away... never have a problem.

It is also possible that the torque wrench is out of calibration. All you have to do is drop the thing once and you're out of business. I do not use the "clicker" type. I use the beam type, and nobody borrows my torque wrench so I know its history. A clicker type is fine as long as you spend several hundred dollars on it (the good ones cost $700+). I have witnessed the less expensive clicker ones going out of calibration very easily. They are prone to getting dirt in the internals.

I would guess that people have more problems with the lower (shorter) bolts because all of the water is not always out of the block when they are re-installing the heads. This increases the possibility that the threads are contaminated. Also, being on the edge, there is less gasket shrouding the area around the bolt for sealing. You do have to use a solvent on the threads just before you add the sealer. Wire wheeling does not remove the oily residue or antifreeze. When I sandblast parts and then wire wheel them, I wipe the part down with lacquer thinner before I paint them. The amount of residue still on the part is amazing. If I forget to use lacquer thinner, the part ends up all "fisheyed", and I have to start all over again.

RE: The Aviation sealer- I tried that as well. It's too watery. I also tried silicone a few times. I had 50/50 results with silicon, so I don't use it for head or intake bolts.

Building engines for yourself is one thing. Taking peoples money for it to pay your bills is entirely different. If my engines leaked, or if I had to go back and diddle with leaky bolts, I would have quit 35 years ago.

I didn't know that ARP recommended or provided teflon sealer- they must have a special formulation. I'm sticking to Permatex #2. I have a 100% success rate with it.... with clean dry threads and a good torque wrench.

By the way- with Permatex, you don't loosen the bolts and retorque. This will increase the chance of a leak because you will lose some of the sealer.

"I've heard, and read that ARP recommends you tighten head bolts or studs, in order, using three steps 'till you reach max torque. Then, REPEAT the process two more times. So they recommend that you torque down and loosen the bolt three times before you do the final torque."

I have a lot of respect for ARP... but I never have to screw around like this. Must be I'm just lucky. Yeh, right. :)

 

Basically agree w/ Tom454.
You can get very good bolt thread sealer from GM.