Engine chattering [Archive] - GrandAmGT.com Forum


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01-31-2012, 01:19 PM
I have a 2000 Grand AM GT with the 3400 v6 in it with 115k~ miles. These engines are notorious for having a bad lower intake manifold gasket and my car has been showing signs of it. About a year ago I noticed that my engine temperature was getting high whenever the heat was on. I found the problem was that the coolant was low and discovered a pool of coolant around the engine block. So I knew that the gasket was starting to go bad then, but assumed it was just leaking externally. Occasionally I would have to add more coolant, but now flash forward to this week.

I go to start the car Monday and it is chattering bad like there isn't oil getting up to the lifters. This happened before about 2 months ago, but went away after a couple of minutes. I let the engine run for about 3 minutes, but it didn't go away. I looked at the oil cap and noticed it was milky on the top like coolant was getting in the oil. I checked the dipstick and the oil in the oil pan looks good. Low oil pressure light isn't coming on.

I know the gasket is bad, but I don't know why all of a sudden my engine is chattering. Could someone give me some insight on this?

Is this related to the LIM gasket? Would replacing it fix it?

01-31-2012, 03:55 PM
Depends on how long you've had a milky oil cap...
If it's been going on for a long time the engine is bound to blow sooner or later from bearing damage. If the internal leak hasn't been allowed to go on for too long you can replace it and it'l be fine.

Not sure if the chattering is related, it may be, some of the experts on here can chime in.

01-31-2012, 06:15 PM
Your lifters are making that sound. Congratulations on ignoring your leaking lim to the point your engine is being destroyed. Your bearings should be goin pretty soon.

01-31-2012, 09:13 PM
It's hard to say really. It's most likely lifter noise. Sometimes they wear out and go bad on their own. It could also be failure from poor lubrication caused by the leak though, if it is indeed leaking internally as well as externally. When it leaks on the area of the gasket inside the engine, the coolant drips down into the oil drain galley right by the outer lifters, so it could have affected them. This is why you don't ignore maintenance issues with your engine and just let them go. How many miles are on your current oil? If the cap looks milky but the oil on the dipstick looks fine, it may be that it was just a slow leak over time and the oil hasn't been in long enough to change, but the cap has build up from it.

Fixing the LIM gasket now will not make your engine noise go away. I would take it to a shop as soon as you can though and have it torn down and inspected. At least down to the heads, and inspect and replace any bad lifters, look for signs of any other possible damage, and put back together with a new LIM gasket. Use the fel-pro premium set and you won't have any more leaks. Use good oil and cross your fingers and hope the rest of the engine is still in good enough shape to live for a while.