Forgive my lengthy post that follows...but I don't know what parts of this may be relevant.

First the particulars: 96 Bonneville SE, 159,800 miles, no upgrades or mods.

Car was my daughters until she headed off to college. Sat in my driveway for 8 months with fuel pump leak and transmission oil leak. Son got his license, decided to fix up the beast. Replaced the water pump, transmission oil and filter and after finding it still running rough, identified two bad ignition coils, replaced those, and put new plugs and wires on (what the heck) and the car was purring like a kitten (better than the 3 years my daughter drove it in fact). Two back plugs 4& 6 I believe, had evidence of an old oil deposit that had cooked down. No evidence of a recent leak. Car is sluggish to start so at that point I'm planning to check the battery and/or starter in the near future...but see no reason the son can't take it out for limited use.

So, 150 miles later, after much more than limited use, my son slams on the brakes to not miss a turn and the CIL starts blinking. It starts running a bit rough but nothing major, he parks it and a couple hours later tries to start it and it cranks, but won't catch. His friends notice the spillover coolant tank is empty so add water and try adding a little oil.

Engine is throwing code P0301 when I arrive to check out the problem.

I check all of the battery cables and grounds and clean some corrosion, make sure all the connections are tight (battery shelf is rusted out and batter can slip in a high G maneuver). Low coolant makes me fear a possible coolant leak into manifold. I pulled the plug on Cylinder 1 and plug is clean and dry. Reinstall and try to crank the engine. It still turns but won't catch...though a couple of times off and on it acts like it'* going to catch. There is fuel pressure in the rail (didn't check exact pressure but shot out pretty hard from the Schrader valve) and it looks as near as I can tell in direct sunlight that there is a spark.

Didn't bring a DVOM but since battery is over 4 years old, I run out and grab a new one. When everything is hooked back up, the car tries to turn over only very slowly now and gets worse with each attempt until it finally goes "CLUNK" after three tries and refuses to turn over at all. Since there had been sluggish starts already, thought it might be the starter so I pulled that and took it to Advance Auto for testing. It tests out fine.

Get back to the car and am worried that I may have overlooked a potential hydrolock by just checking one plug so I pull all 6. All of them are now covered in fresh oil, including the plug in Cylinder 1. Seems that clunk was something major. I thought at first it was coolant, but after wiping it off I confirm it'* oil. No milky signs to indicate water leakage. Oil in pan is fine with no milky indication of water either.

Not sure where to start looking for a problem now. Bent valve or connector rod? Seems unlikely since the car wasn't at speed. Blown valve cover gasket(*)?

Any ideas or assistance would be terrific. Let me know if you need any additional info. Thanks.

The issue that occurred is the UIM has failed. This pushes coolant into the LIM and once a half gallon fills that it spills into the cylinders soaking the plugs and keeping it from starting.

You'll want to order a new UIM, yes the manifold (Rockautio has great prices) and also pick up a set of the alumunim LIM gaskets. While you are already there, it'* worthwhile.

After you get it back together pull the plugs and crank it a bunch of times. Clean/dry the plugs and give it a try. You may have to dry them more than once. Soon as it starts to catch, they'll clean up and all fire again.

That'* good news. When I saw oil instead of coolant on the plugs, it freaked me out. I'm familiar with Rock Auto and really like them. Unfortunately, I can't seem to find aluminum LIM gaskets. Do you have a part number or something I should be looking for. I know Felpro seems to have decent stuff but the only two LIM gaskets I saw were composite on steel and rubber. Thanks for the quick reply!

Are you postive it'* oil? There'* no oil that can get into the heads unless you have bad valve seals. Bad seals are very uncommon, it can happen though.

A bad UIM will put coolant on the plugs, which when combined in the cylinder with carbon can sometimes be mistaken for oil. That'* what I thought last night.

On the gaskets.. It'* a dealer thing. Although I do hear that Fel Pro has a part number for an aluminum gasket.

Actually...no...I'm not sure it'* oil. What you say makes sense...it seemed a little thin to be oil but it was a nice brown color (note that the anti-freeze has been the green stuff since we bought the car over 4 years ago) and didn't appear milky (which I thought it probably would given all the gunk in the upper manifold) so I assumed it was oil. I guess I can breath a bit easier and go pull the manifold off and dry it out before it eats the engine. Thanks again!

And chattin about it makes me think further.

When the EGR area bursts and floods the LIM you could get an oily/coolant like wetness on the plugs. The LIM typically has a decent amount of oil sitting in it'* channels from the PCV system. Then the coolant comes along and fills the LIM (literally a half gallon) before the fluid spills into the intake runners. Being that there'* no real flow or mixing of the two, the oil would float to the top and be the first of the fluids to find the way into the cylinders.

I am still thinking this is the UIM and can be confirmed if you remove the throttle body.

What I'm reading here tells me the stove pipe failed on the UIM. Remove the throttle body and look in to the intake. You will see the EGR hole. You will also see coolant pooled up. The EGR carbons up the intake bad, coolant washes that off and looks like oil, as bill said.

96? wont these work for him? http://intense-racing.com/Merchant2/...tegory_Code=GH

I'll get back to the car this evening and pull the TB and have a peek. Sounds like good news though...I was trying to figure out how I'd have gotten oil in there and all the scenarios were bad. Got a question on the parts though. Rock Auto has the Dorman manifold kit...but it looks like it'* the 1st type, i.e., uncorrected manifold that would lead to a repeat break in about 60k. So I assume I'm looking for the Dorman with the blue gasket vs. orange? As for the LIM gasket, I found the aluminum ones in a couple places, but then I've also seen the Fel-Pro PermaDryPlus (MS98014T) gaskets at Rock Auto and other places. Can't quite get a good description of what "PermaDryPlus" means...but I'm thinking not aluminum. However, as it'* more expensive...wondered if it was a newer, better alternative or if I should still go after the aluminum gaskets?

Not sure on the gaskets. However, a option is to block off the two coolant passages that go in to the UIM. They really arn't needed, they just run a small amount of coolant in to the throttle body. block them off and no more coolant will go past the EGR tube. So no more coolant leaking in to the engine.

You found the aluminum Fel Pro. I haven't seen it, but the T designates it to be the aluminum one from what buddies have passed on to me. I forgot exactly what the number was..I definately remember the letter at the end.

Dorman kits are all beefed to my knowledge, containng smaller stove pipes, o-rings etc etc all the goods you pretty much need except the LIM gaskets.

I'm a big fan of blocking the coolant ports. Either with threaded NPT plugs or by blocking the hjoles in the UIM with something like JB Weld after scuffing the bores. The coolant going to the throttle body is pretty useless. Which you'll see when you pull the TB. It'* supposedly to keep it from icing at the North Pole when Santa jumps in his Bonne to deliver presents (yeah..that sled went out years back, he'* cruising an SSEi.).