I have a 96 SSE with about 127k. What are the early signs of UIM/LIM failure, if any?

I have a terrible burnt oil smell coming from the car and the coolant tank has been dry twice in six monts. I'm only a novice mechanic, not good at digging into engines.

The oil pressure is fine after having the entire system (incl. the screen) cleaned last year. It doesn't go even close to red. It used to top out at 120psi, but the cleaning solved that problem. I have noticed the coolant reservior empty twice in about six months. This time when I topped up, I marked it exactly and look at it about every three days. Not much movement over the last 10-15 days. I did just have the tranny replaced. There is no milky look to the oil and no color to the exhaust. The oil is blackest black, even after a few days after a change. I've had the oil changed every 3k religiously.

I saw this page http://www.bonnevilleclub.com/forum/...e=article&k=38 and will look to see when the manifold was made if that helps.

Thanks ahead of time for all the advice.

Although coolant will evaporate, it doesn't do it that fast. If you are not seeing signs of a leak then its probable that you have the Upper and/or Lower intake manifold leak.

The upper is the easiest to spot. Drain a little coolant and then remove the airtube from the TB, then remove the 3 bolts from the TB and set it aside and look inside the UIM. If you see crude built up around the EGR stovepipe that comes thru right at the opening where the TB bolts on or collant there - then you have the dreaded leak. If you've never changed the TB gasket, have a replacement handy.

I would strongly recommend changint he LIM gasket while doing the upper, its not that much more work. I did both mine in the driveway.

I agree with Popatim, if you see no external leak, with your mileage, you are due. I would buy the APN kit described in Techinfo article 38 - it will come with a smaller stovepipe that will fit in your LIM. With aluminum LIM gaskets and a new elbow - you should be good to go.

If you are still running Dex-cool, get it out of there.

DEXcool is the devil. This isn't a joke. Get the DEX compatible prestone long-life. Lose the DEX entirely.

Many thanks. I never knew about the DEX problem and will drain it right away. I saw several messages about where to get the new UIM. I'll search the forum for step-by-step instructions. I have suspected the UIM problem was occuring but was never sure.

It wouldn't hurt to change your oil ASAP as well.

You've got very similar symptoms to what I had. I would slowly lose coolant from the reservoir, but there was no visible leak anywhere. What it ended up being was a LIM gasket failure, which when it finally blew, ended up spraying coolant all thru the intake.

I highly recommend using the aluminum gasket and the APN upper. I used that to repair my 96, and it runs better now than when I got it.

when my upper failure started and as it worsened my oil never really changed in appearance. This most likely because the moisture was being added as vapor by piston ring blow-by instead of liquid. I did notice some creamy colored oil up underneath the filler cap, look there. Listen for abnormalities in normal running too. My motor developed a loud lifter tap on cold start up most likely because the properties of my oil were changing. Look for an abnormal amount of light colored smoke under heavy acceleration. Under load, don't go revvin your motor in the driveway :p

Many thanks for the help here.

I've still got the burnt oil smell (but no coolant loss after four weeks post- top off and no leaks) but want to make sure that I really need to do the UIM/LIM replacement eventhough it seems inevitable that I will have to do it .

However...

I vaguely recalled a Goodwitch guy back in Michigan telling me that a "manifold" recall had been performed under the extended warranty. Having had too many drinks and having owned the SSE for too long I went into my "Bonneville" file and found that at 59,530 miles an upper intake manifold fracture recall was "done"( car now has about 130k on it). This was listed as campaign 96045. I also found a reciept for a bunch of coolant had remembered that I drained the dex-cool in my apartment parking lot at about 70k miles. I had a friend in a Lansing factory who said get rid of it. I did.

Does anyone know was this "campaign" was and what would they have done? I'm trying to figure out everything before I dig into the engine.

By the way - almost two months with the GXP and IT ROCKS!

Did you ever find anything else out about the recall? Did you ever go ahead and replace the UIM?