Old Coolant Causing Blown Head Gasket?
10-03-2003, 09:35 AM
#21
Race Director
Re: Old Coolant Causing Blown Head Gasket? (TheCorvetteKid)
Dude, relax. It sounds like we're all on the same page here anyway.
I don't remember anyone stating that expansion was the problem, but maybe I didn't read carefully enough :confused:
I don't think anyone could state NO head gasket problems exist period, but I think Suncr is saying that GM has less head gasket problems. I've owned fords, chryslers and chevys and I can attest to that.
Well that is interesting, but I still don't think that's what's going on with this guys engine.
So therefore we agree it was probably bad installation or wrong parts.....so what are we arguing about? :confused:
What I understood about what he was saying is that having more head bolts is BETTER for gasket seal and longevity, unlike ford heads and gaskets. I don't remember reading anything about it causing overheating/expansion. :confused:
Again, then we all agree it's from improper installation.
:iagree:
:iagree:
Pure water can erode/corrode anything after enough time, but the difference between this guy's engine and the grand canyon is several million years. I'm not buying the caustic theory on 21 mo. old coolant....again, we all agree right :yesnod:
Let's all just take a deeeep breath and give each other a hug :grouphug:
:cheers:
The fact that aluminum and iron have different coefficients of expansion has ABSOLUTELY NOTHING to do with a leaking head gasket or an overheating condition.
...and yes there was a GM head gasket problem
A problem which was the result of incorrect head gasket types being used in production. The gaskets (produced by Detroit Gasket, by the way) that where used did not substantially prevent the galvanic corrosion that occured between the head and block. This corrosion erroded the gasket material AND the deck surfaces of the block and heads, causing combustion gasses to come in contact with the coolant, and thus the overheating condition.
I will agree that if the engine has already been dissassembled once before, that there is virtually no likelyhood of the current problem being a result of the original gaskets since they are no longer on the vehicle. But, the mechanic who conducted this repair could have VERY easily used improper gaskets. Don't believe me? Go to FelPro's website and search for the heat gaskets that are recommended for the '88-'91 Corvette L98. It will come back with #7733. WRONG!!! These gaskets are fine for the iron head versions (Camaro, Caprice, etc...) but NOT the aluminum head L98! The FelPro database is wrong, but if a mechanic didn't know any better, he's just use these. And within 2 years (not far off from the 21 months that our friend here encountered this problem) you're replacing the gaskets again.
FIVE HEAD BOLTS VERSUS FOUR!?! YOU'RE ATTRIBUTING A HEAD GASKET LEAK TO THE EXISTANCE OF ONE ADDITIONAL HEAD BOLT PER CYLINDER?!?
I firmly believe that the problem is because the new AFR heads where not retorqued after a few heat cycles. This 'heat-float' is a common problem with NEW castings,
High temperature thread sealants never completely harden.
but the problem wouldn't have taken 21 months to surface - it would have been immediate.
Bottom line, anybody who believes that engine coolant isn't caustic and that it isn't capable of over time doing considerable damage to whatever it comes in contact with, is only kidding themselves.
Let's all just take a deeeep breath and give each other a hug :grouphug:
:cheers:
10-03-2003, 11:32 AM
#22
Le Mans Master
Re: Old Coolant Causing Blown Head Gasket? (vvv90)
I don't think this an installation issue as much as a prep issue, but the time for this issue would probably have been better if it was 1990. My problems were evident at about 21,000 miles or by 1992 (still under warranty) and had I been more astute, I would have insisted that the dealer find out why my coolant was "really dirty", the heater core plugged and the thermostat bolt (which they broke) fully welded to the manifold. These problems existed in spite of annual coolant changes. I would have also paid more attention to the complaints that were rolling into the NHTSA complaint center (a couple - all of which I believe are long since settled lawsuits - were still there the last time I looked). Of course the internet didn't exist in 1992, so if you wanted this information, you had to write to get it. At 55,000 miles or 3 years ago, the gasket finally let loose and thanks to the Forum, I finally got the lowdown on what was wrong.
GM issued it's Bulletin about the issue in December 1990, using language that the heads and gaskets were redesigned to deter "galvanic corrosion" and it was applicable to all aluminum head engines. Those changes didn't make it into production until the 1991. The "galvanic corrosion" language no longer appears in the Bulletin for reasons I've never figured out. Was GM's problems any less than Ford & Chrysler? They issued similar Bulletins.
I don't think retorquing head bolts is necessary or a great idea. You won't find the procedure outlined in any service manual. It isn't done after the "cold" run at the engine factory (and when I was at the assembly plant, they made it fairly clear that the first time the engine is "fired" is when it's driven the 20 or so feet to the dyno where it's run for 17 minutes. Afterwards - given the nature of the LS1 - I was a little taken aback that they don't even bother to check the oil). The lubricity provided by the sealant is something you don't want after you've achieved final torque so there is a "cure" that takes place providing maximum friction for the fastener ensuring that it doesn't work loose. Twist it after the cure and you destroy that chemistry as well as the seal.
GM issued it's Bulletin about the issue in December 1990, using language that the heads and gaskets were redesigned to deter "galvanic corrosion" and it was applicable to all aluminum head engines. Those changes didn't make it into production until the 1991. The "galvanic corrosion" language no longer appears in the Bulletin for reasons I've never figured out. Was GM's problems any less than Ford & Chrysler? They issued similar Bulletins.
I don't think retorquing head bolts is necessary or a great idea. You won't find the procedure outlined in any service manual. It isn't done after the "cold" run at the engine factory (and when I was at the assembly plant, they made it fairly clear that the first time the engine is "fired" is when it's driven the 20 or so feet to the dyno where it's run for 17 minutes. Afterwards - given the nature of the LS1 - I was a little taken aback that they don't even bother to check the oil). The lubricity provided by the sealant is something you don't want after you've achieved final torque so there is a "cure" that takes place providing maximum friction for the fastener ensuring that it doesn't work loose. Twist it after the cure and you destroy that chemistry as well as the seal.
10-03-2003, 07:18 PM
#23
Racer
Re: Old Coolant Causing Blown Head Gasket? (SunCr)
The "galvonic crossion' issue is why GM recommended using the "pellets" in the coolant.
10-04-2003, 01:20 AM
#24
Le Mans Master
Re: Old Coolant Causing Blown Head Gasket? (Pats90)
I don't know - it's in the Cooling Section of the Service Manual without any explanation, but it wasn't mentioned in the Bulletin about the head/gasket redesign. I don't know of any magical tablet that will stop electrolysis between two dissimilar metals connected to each other and in contact with a glycol/water solution. Of course GM's current position is that Pellets were never used at the factory and that they shouldn't be used, though they remain widely available at every dealership I've been too.
