Symptoms of head gask failure

[Cooter]

My '96 Lumina has had issues with temp fluctuations, had a bud who is a good mech look at her and says I have freeze in the oil and oil in the freeze....intake gasket.

So I'm worried about head probs but guess I'm gonna dump the $450 for the intake and hope for the best. She's got 166K on her and is starting to rust - she's been so good but I hate to put a couple hundy in her and then have the head gasket or some other major bull break me.

So basically, anything to look or watch out for more upcoming probs than the head gask? - ways to separate head from intake problems with those 3.1 GM knockers....just like the 3.8s and all the rest? BTW - I can hear my old girl knock on a cold morning from inside the hut.

[Jeremy airjer W]

If the oil is milky it its too late. Especially since you already metioned that it is knocking. These motors are especially sensitive to coolant in the oil. lower end bearing failure is common with coolant in the oil. Typically the 3.1's do not have head gasket issues but the oil in the coolant is a little troubling. The 3.4 liter is more prone to head gasket failure particularily in the minivans for some reason.

IMO, it is not worth investing in the intake gasket since you can already hear the signs of the motor failing. If it is in decent condition and you think it is worth it it may not be a bad idea to replace the motor with a good used one. Many salvage yards offer good warranties on there motors. Some replace all of the known gaskets that fail before you buy them. We have installed many of these over the years with no problems.

[Macgyver55]

I wouldn't write it off just yet. Many of the 3.1 motors have piston slap noise when cold, it may be that. It depends on if this is a new knock or one that he had all along. Other than the intake problem these are quite incredible motors. I personally had one recently that had 227,000 miles and still ran great, used no oil, but knocked when first started. Always did! I have seen others with over 300,000 and still going. Its a bit hard to say without seeing it, but if the coolant hasn't been in too long, and the rest of the vehicle is ok, I guess I'd be probably inclined to go for it.

[Gadgetman]

Hey Macgyver, you bring up something I have been wondering about for a couple of months now. My 2000 GMC Yukon has started with the "piston slap" this winter. Sounds like a diesel for a couple of minutes when it is first started in the morning and then is fine. when I asked Mr. Goodwrench about it I was told it was piston slap and was "normal" I have 113,000 on the truck and dont plan on getting a new one any time soon. Are they blowing smoke up my skirt or is this an acceptable diagnosis of my problem. Doesnt use any oil and had the head gasket replaced at about 90,000.

[Macgyver55]

I'd prefer to describe it as "common" moreso than normal. My own Tahoe is doing it now with 148,000. I don't like the sound of it myself. But, vehicles that have it dont suffer any ill effects from it that I know of, other than the noise. Several of our work trucks have done it for years without a problem.

Did you actually have a head gasket replaced, or do you mean the intake gasket? I've never yet had to replace a head gasket on a Vortec 5.3 or a 5.7

[Gadgetman]

Just went and pulled the original work order and it was a head gasket. Fortunately I discovered it before it could cause any other damage. I have done a little web surfing and see that a class action suit was filed against GM for piston slap but I am not able to determine the out come of this case.