: Headgasket



89 D'elegance
06-24-05, 03:26 PM
What would cause a headgasket to go? This car is mint with 75k on it bought from the second owner just wondering what causes them to go, I know the car wasnt driven hard because the original owner was a senior. Looks like I will just take it off the road because I dont have the money to fix it now and man, I love that car! :banghead:

N0DIH
06-24-05, 06:29 PM
Cooling system negligence will accelerate it. In my 350 Olds, unknown person who torqued the gasket, so when I did a hard WOT run it blew (that is how I learned the chamber pressures can pressurise cooling system, and boilover evertime on a warm day when I shut it off).

Excessive turbo boost

Crappy manufacturing tolerances, some bolts torqued well, some not, coupled with stock turbo boost levels...

I have had my share of head gasket failures. 2 on a 301 Turbo, 1 on an Olds 350. I take my time on assembling engines when it comes to head gaskets and bottom ends. I have learned the hard way to do it right the first time.

N0DIH
06-24-05, 06:45 PM
In my car (77 350 in a 85 Cutlass) I ran stop leak and ran it for another 70K miles. So don't fret it. If it isn't losing coolant while you drive, then drive it. Eventually it hydrolocked and would not start. Then fix it. Save the $$ and fix it before winter sets in. Ensure it is always topped off on coolant daily.

It isn't terribly hard to fix. Just need a garage and some time.

davesdeville
06-25-05, 05:26 AM
Pulling the heads and replacing the gaskets isn't a really hard process on these older iron engines. No timeserting BS to deal with unless you mess something up bad. I'd say you could do it for under $100 or so in a day or 2 if you DIY.

89 D'elegance
06-25-05, 07:26 PM
If the head gasket is bad should it overheat even without air, overheating seems to happen with air, not without??

N0DIH
06-26-05, 04:54 PM
You can't really diagnose it by determining if it overheats or not.

For me, I would start by letting it cool and pull the plugs, read them closely. With a magnifier if you can. If there is coolant (antifreeze specifically) in the chamber, you will see little silver speckles on the plugs white insulator. Often the plug will be spoltlessly clean, and the others will not. That is your offending cylinder. A compression check may also reveal the cylinder. A leakdown test will almost surely show it.

If all that passes, check for antifreeze in the oil. It can be blown from the crankcase to the coolant, and not have any effect on the chamber pressures.

As a crutch, you can try to add in stop leak and then retorque the head gasket. Do the proper sequence, and do not back off the bolts first! You may need to add at the most 5% more torque to get it to torque. You might get lucky, you might not. It makes sense, but....

AC will make it worse, as it is hotter and more load on the engine, so AC may be exceeding the coolant capacity if it is comprimised already. Upping the % of water/antifreeze mix to 70% antifreeze/30% water may help some, but over 70% you comprimise the freezing point.