Bob, Finally uploaded the pics to my new laptop.

Rich, Thanks for the help with all the part numbers.

Job was a cinch thanks to all you guys on the Forum.

I'm sorry guys I dont have more pics, it was -10 to 0 degrees in my garage that day and I wanted to get done ASAP. You get the Jist of it. This 3800 had coolant pooling up on top of the LIM near the fuel injectors. and valve covers. Also Bob was right, 130,000 on this ones Odometer, all 4 ends of the coolant elbows broke off and had to be dug out of the tensioner and LIM.

Once the LIM was off, I immediatly was able to find where the old gaskets failed. The two top ones are of one leak, and the bottom one is from another leak on the opposite bank.

http://photos-b.ak.fbcdn.net/photos-ak-sf2p/v647/44/39/500370123/n500370123_1737009_7162.jpg

http://photos-e.ak.fbcdn.net/photos-ak-sf2p/v647/44/39/500370123/n500370123_1737012_8005.jpg

http://photos-f.ak.fbcdn.net/photos-ak-sf2p/v647/44/39/500370123/n500370123_1737013_8284.jpg

A couple of the inside of the top end of a 3800 for those of you who have never had one apart...

http://photos-c.ak.fbcdn.net/photos-ak-sf2p/v647/44/39/500370123/n500370123_1737010_7454.jpg

http://photos-d.ak.fbcdn.net/photos-ak-sf2p/v647/44/39/500370123/n500370123_1737011_7731.jpg

And finally the last pic I have is of the new Fel-Pro gaskets going back in. (yes I did glob silicone into where the valley gaskets meet the LIM gaskets, dont forget this step if you change your LIM gaskets).

http://photos-b.ak.fbcdn.net/photos-ak-sf2p/v647/44/39/500370123/n500370123_1737017_8618.jpg

Thats it! I was hoping to do a nice writeup, but it was just so darn cold. Job was pretty easy. Car started right up, and ran good. No more leaks. Just make sure all the bolts are torqued correctly if anyone attempts this.

Thanks guys!

Very interesting post Tim. Thanks for sharing. I have a small leak in my lower intake gaskets. Or so I was told. However, I Don't have the tools or the nerve to attempt this myself. For now, I'm just closely watching my oil and coolant and I'm not losing either. Eventually I will give this the attention it needs. Or I'll be forced to have it done.

Very interesting post Tim. Thanks for sharing. I have a small leak in my lower intake gaskets. Or so I was told. However, I Don't have the tools or the nerve to attempt this myself. For now, I'm just closely watching my oil and coolant and I'm not losing either. Eventually I will give this the attention it needs. Or I'll be forced to have it done.


I have the same thing I was told 3 years ago, and my car hasn't failed yet, still going strong at 103k.

you guys should give it a shot! Its a cinch. Remove the alternator and bracket, belt tensioner, intake duct, injectors with fuel rail, then the UIM can come off, and then the LIM. Clean it all up, and reassemble. Pretty easy, pretty straight forward. The t-body can stay on the UIM, but the throttle cables need to come off. CHange the oil, add coolant.

I have the same thing I was told 3 years ago, and my car hasn't failed yet, still going strong at 103k.

This one started out as a slight leak too. Last summer the LIM gaskets were diagnosed at a shop as leaking after an oil change. It went from April to Jan without Major Leaks until recently. Then the gaskets gave out and the owner had to keep adding coolant every other day. He said that it was only leaking externally, but looks to me like where the gasket split, the coolant was also making it to the crank case.

***56K WARNING***

Good post Tim!

The issue of LIM gaskets on the NA SII 3800 engine regardless of GP year '97-'03 is not whether they will go bad or cause issues but just a matter of when.

Here are some better resolution pics (800X600) out of my collection on the upper part (UIM) and new LIM gaskets (FelPro).

As soon as I get a chance I'll be posting a detailed tech procedure at Tips & Maintenance. I've done 4 of these jobs over the past several years.


Getting fuel rail off. Leave fuel pressure and return lines connected and tie up
http://i5.photobucket.com/albums/y186/lizzywiz/DSC02561-1.jpg


All stuff in the way removed and UIM pulled
http://i5.photobucket.com/albums/y186/lizzywiz/DSC02575-1.jpg


UIM plenum and throttle body removed intact
http://i5.photobucket.com/albums/y186/lizzywiz/DSC02576.jpg


New FelPro brand UIM gasket. Old UIM plenum was re-used
http://i5.photobucket.com/albums/y186/lizzywiz/DSC02571.jpg


Old deteriorated LIM gaskets and end seals
http://i5.photobucket.com/albums/y186/lizzywiz/DSC02590.jpg


New Felpro brand LIM gaskets
http://i5.photobucket.com/albums/y186/lizzywiz/DSC02593.jpg

Thanks for showing me up Bob! =P He He!

No, seriously, nice work. Was this the wife's buick? I remember you had to replace the LIM gaskets in that 3800 not long ago.

Looks like you gaskets gave out in about the same spot as mine. Coincidence? or just faulty design?

How much longer before the LIM's go in my GTP would you guess? 107,000 right now.

At about 265,000 miles I had higher than normal Potassium levels which indicated a possible coolant leak into the oil. It never got any worse and the UIM gasket blew out at about 306,000. It was June and I had a spare ride so I just took my time and did the job myself. I figured "what the heck, what do I have to lose"? I took pictures and labeled all the hoses and connectors cause I'm pretty forgetful. This was the deepest I'd ever been into my engine before and it was a pretty good experience. All turned out well with Bob and Rich's help.
If you have any mechanical skills at all, I think you can do it at home.

Tim and Wally, you are both very welcome for the help.

Wally, I have a fine-tipped silver sharpie pen (it's a sharpie marker that writes in metallic sliver so you can see it on the black plastic) in my tool box that I use for marking connectors. Normally, everything goes back where it came from as the wires kind of form themselves, but it never hurts to be sure you're gonna put them back correctly.

Was this the wife's buick? I remember you had to replace the LIM gaskets in that 3800 not long ago.

Looks like you gaskets gave out in about the same spot as mine. Coincidence? or just faulty design?

How much longer before the LIM's go in my GTP would you guess? 107,000 right now.

Yup! The LIM port gasket at cylinder #1 was the main reason for the coolant loss. No driveability issues per se. No misfires. Upon removal of the #1 spark plug I could see what appeared to be coolant burning off. A deep reddish color versus the nice tan color the other plugs had. Also, it affected positive crankcase ventilation and triggered a MAP sensor DTC. After removing the MAP sensor and PCV valve I could see, smell and taste coolant residue in the channel that goes up into the UIM from the LIM. Also, there was coolant and condensation on the oil filler cap and I could see a little steam from the cooling system coming out the oil filler. The coolant loss showed up at around 130K miles. Luckily it was nipped in the bud in time without causing any internal engine damage. The UIM plenum was fine and just needed a good cleanup which was a PITA by the way.

Design? :lol: Obviously the original OE GM gaskets are crap!

On your L67 GTP I would replace the LIM gaskets as soon as possible as preventive maintenance. I used the GM aluminum framed LIM gasket set and the OE GM supercharger gasket. Do not use the aftermarket Garlock gasket for the supercharger.

I have a fine-tipped silver sharpie pen (it's a sharpie marker that writes in metallic sliver so you can see it on the black plastic) in my tool box that I use for marking connectors. Normally, everything goes back where it came from as the wires kind of form themselves, but it never hurts to be sure you're gonna put them back correctly.

I use the same marker. I label everything including hoses with the alpahbet system. A-A, B-B, C-C, etc. Has worked well for me and I don't have to remember every detail. Love those Sharpies.