: warped heads common?



mountain14er
08-07-06, 10:39 PM
I recently got the diagnosis of combustion gases in the coolant so I'm gearing up to do the head gasket job. I want to have everything ready when I start so I'm wondering if I should buy thicker head gaskets and line up a shop to resurface the heads in case they are a little warped. Are warped heads on a N* common?

I was told the vehicle had green coolant in it recently so I'm guessing that is the cause for the bad head gasket but not certain. Thanks for the help, I'm just trying to get all my ducks in a row.

dkozloski
08-07-06, 11:00 PM
Warped North* heads are almost unheard of.

JimD
08-07-06, 11:17 PM
Easy stuff first. Do yourself a favor and consider the test for combustion gases in the coolant as less than 100% accurate and repeatable. The definitive test is to pressurize each cylinder with shop air (100+ psi) and look/listen for air bubbles in the cooling system reservoir OR out the exhaust pipes.

Head warpage is as rare as a live dinosaur sighting.

I doubt that OEM GM gaskets (the only gasket to use) are available in other than one thickness.

Maybe your engine was factory filled with green coolant?; you did not specify year. Pre 1996 had green; 1996 and later had orange or pink depending on your color perception (Dex-Cool). However; the color of the anti-freeze has nothing to do with gasket failure. The lack of coolant corrosion inhibitor maintenance is the leading cause of gasket problems.

If in fact you have a failed head gasket, you must get your Time-Sert ducks in a row also.

zonie77
08-08-06, 12:26 AM
Did you get a factory manual? Look at the N* head gasket repair threads in tech tips?

As JimD said, get a timesert set. If you check ebay they come up used pretty often.

The heads are great, rarely warp or crack.

mountain14er
08-08-06, 12:20 PM
The car's a 99 Deville and I've got the factory manual on the way. I'm planning on doing all 20 timeserts. Regarding the gren coolant, I was inferring that it lead to corrosion on the gaskets and then the failure.

How could combusion gases in the coolant not be definitive? Believe me, I don't want to do this job if not necessary.

zonie77
08-08-06, 02:16 PM
It doesn't matter which coolant is in it, they both work. As JimD said, it's the breakdown of the corrosion inhibitors.

clarkz71
08-08-06, 02:45 PM
How could combusion gases in the coolant not be definitive? Believe me, I don't want to do this job if not necessary.

The cylinder pressure test is just a more positive way to verify the gasket failure. As you said, you don't want to do this job unless absolutely necessary.

zonie77
08-08-06, 06:16 PM
I think if the coolant has been in there a loonnng time you can get a false positive. If you are loosing coolant, having overheating problems, and the coolant is fairly fresh it isn't likely to have a false positive.

Ranger
08-08-06, 08:15 PM
The car's a 99 Deville and I've got the factory manual on the way. I'm planning on doing all 20 timeserts. Regarding the gren coolant, I was inferring that it lead to corrosion on the gaskets and then the failure.

How could combusion gases in the coolant not be definitive? Believe me, I don't want to do this job if not necessary.
If combustion gases are found in the system, then it is definitive. However, the head gasket breach could be in a place that it is leaking into the exhaust ports and being burnt. Then there will be no exhaust gases in the coolant, thus a false negative.

mountain14er
08-10-06, 11:00 AM
Thanks Ranger, that's what I was guessing. Also, the coolant is new with less than 1000 miles on it. It's leaking out the overflow at higher rpms and does run a bit hot when it's really warm out. With all of this and the gases in the coolant, it looks like I'll be doing the head gaskets.

mikeay
08-10-06, 11:36 AM
I had my heads resurfaced when it was out, just to clean them up. Not much was taken off. You might want to do the valve stem seals also or at least make sure that they are not hard/brittle.