What are the exact problems that occur when the intake manifold gasket goes on a 3.1/3.4L engine. Is it just an increase in wear metals, which leads to a reduced engine life or are there other things that go wrong.
I'm not sure exsactly what you are trying to focus on, but I'll tell you what I know. The main problem when these gaskets leak is that the coolant leaks and then ends up in the oil/ crankcase, causing problems. Oil mixed with water and glycol (emulsion)is not good at preventing engine wear and deposits. The word sludge comes to mind, too. The oil's protective additive package is quickly overpowered by the incoming coolant. Sometimes noise such as lifters tapping is the first warning you get. Hydraulic lifters have some very small oil passages that won't flow oil if sludge is blocking the flow. For those of us who actually look under the hood once in a while, we may notice the coolant reservoir is low or empty. This is your cue to at least visually check the oil, and then pull an oil sample to check for coolant or water in the oil. In the case of our friend's 2003 Buick Rendezvous 3.4L, they had a loud lifter tap, that signaled them to have it checked out. Their oil had been changed within last 2000 miles, but had very orange look to it (Dexcool). For some reason, the coolant "low level" light never came on, so they never noticed anything up until that point. At 49K miles they paid a local shop nearly $600 dollars to replace the leaking intake gaskets and flush the engine's oil system. The tech told him that their Buick got the newest gasket revision and it would be interesting to see if the new design would be better than the last several generations of same gaskets.
As far as what else can go wrong, my neighbor's brother had an Olds minivan with the 3.1 or 3.4 engine and he had me come across the road to listen to it. The engine sounded like it was coming apart because it was. We pulled the dipstick and found an emulsion that looked like a chocolate milkshake. I told him to stop driving it immediately unless he wanted to destroy the engine completely. He planned to change the oil, maybe run a flush through it, and then go trade it and dump it on someone else, but never got that far. He instead completely ruined the engine driving home that night. Some guy that eventually bought it from him for $600, told him that the camshaft had broken in half and also had severe bearing wear on the crankshaft as well as piles of sludge throughout. He then bought a used engine and put it in instead of rebuilding the old one. Yes this was an extreme case, but I'm sure many others have done the same thing. This van had only 80k miles on it when this happened.
Coolant gets in the oil. That's all you need to know. Nothing will prevent it. If you have a 2003 (I believe this is the cutoff) or older 3.1/3.4 its gonna' happen, period. No exceptions. Sometimes the oil will be found leaking externally also. But more often than not the leak is coolant to oil.
the reason i ask is because my fiance's sisters car is a 98 or 99 grand am gt. it just ate its second set of head gaskets at 140000 miles. the shop it is at now is just piddling around with it. her dad suggested that we get it, put a set of head gaskets on it and dump it. i know there is a possibility of the heads being warped, but no parts would be purchased before the engine was torn down and the heads and other things checked. blue book value for the car is about $3000, im thinking that spending a hundred or two hundred dollars in parts and then some of my time will lead to a $2500 or so sale of a car.
i did a few oil changes on the car in its past and didnt notice anything adnormal with the oil. no large amounts of sludge and such.
I had a girlfriend who had a '94 Olds cutlass supreme with the 3.4V6 and the intake gaskets were shot. evertime you start it cold it'd REV UP! and die! had to do that about 4x's each morning to keep it going. Local GM dealer said it never "reved up" for them. We knew that was **. it did it every cold start for 2yrs, and up and didn't do it for them at the dealer... ok. Small mechanic shop diagnosted it and her dad fixed it. The car was a sweet car... but had the typical GM problems.... anything plastic broke or came un-glued and the car overall had poor quality/workmanship. They've had 30yrs to get their act together... and they still haven't.
The big issue with coolant and oil..is it combines to attack bearing surfaces.
Nothing can be done except repair the engine if it hasnt grenaded already.
However, there is an aluminum framed LIM gasket, combined with new bolts and torquing proceedures.
This should fix things along the lines of the newer 3500 V6 in the Malibu which has so far been ok.
The 5.3 doesn't use the intake manifold to carry coolant between the heads like the older smallblock design did. It uses a water manifold on the front of the engine like Studebaker did 60 years ago. My '96 5.0 Vortech picked up a small external leak from the rear of the manifold where the passages are actually blocked off, I put in a package of GM Cooling System pellets to get through the winter and now 3 years later it's still going, original leak at 155K now at 173K.
well my wifes 2000 malibu just had the gasket replaced. they are finishing up on it now. hers was leaking oil around the seal and had coolaint loss.
it had a tear around one of the o ring seals.
if your coolaint is getting low and no external leaks. then it is pretty sure the gasket is toast
running ARX in it now.
The new LIM gasket on the 5300 is aluminum framed. I have seen it.
The 3500 Value engine in the Malibu is a 60 degree high (er) tech derivative of the 3100 and 3400 gems.
The upper is aluminum, but that is not the problem, its the internal leakage in th lower that usually kills these engines if not caught in time.