Hey All,
Vehicle is '93 Buick Park Ave w/ the series I (vin L) 3.8. She had been consuming a little coolant. Not being able to locate the leak, I thought the upper intake manifold was the problem. After removal and inspection it appeared fine. Put her back together. Then no start. Sounded like it was locked, so I pulled all the plugs - #1 literally had coolant drain out - ugh. I spun the motor and blew out fluids. So I apparently have a bad LIM gasket? Should I also change head gaskets? Car ran great before my "repair" (wife wants me dead). I previously had no heat buildup, no telltale white smoke from exhaust. Just an annoying coolant leak. If I can confirm its only the LIM gasket that would be great, but if I need to swap head gaskets I guess this would be the time to do it. You guys are highly recommended from a merciful fella on the Buick automotive forum and I would truly appreciate any help!
Thanks!
Scott

It'* almost certainly just the lower intake manifold gaskets. The problem with the upper intake manifold failure is with the newer L36 (VIN K) engine, installed in GM cars starting in 1995. Head gasket failure in these engines in not unheard of, but it is extremely rare. I am not sure if the newer aluminum frame gaskets will work on your '93. I am guessing they will not and you will be changing out the old plastic LIM gaskets for new plastic gaskets. Someone else will be able to verify this for us. One thing to check. If somewhere along the line someone installed orange Dex-cool coolant in your engine, you will want to flush it out and replace it with the new "mixes with any type" coolant.

BTW, you can tell the wife you are doing the right thing in finding and repairing the internal coolant leak. The LIM gaskets can fail as yours apparently did, leaking into a cylinder, and often fail by contaminating the crankcase with coolant. When coolant gets into your oil, it attacks and destroys your bearings, effectively ruining the engine. To make sure you don't add to the damage, the safest course is to first drain the coolant. Then change the oil and filter. Then change out the LIM gaskets. When you get it running again, run the new oil for just a little while, then change the oil and filter again to flush any coolant that might have found its way into your oiling system.

BIll, Thanks - good info. Yes, had I been more thorough in my research I would have realized the the EGR stovepipe issue did not affect the UIM in the '93 3.8. No orange coolant, just the regular stuff. I've read up a bit on the alum framed LIM gaskets, I'll research the availability of these better LIM gaskets for the '93. I'm not real knowledgable on this motor...obviously! Any tips for swapping LIM gaskets. I assume the UIM and fuel rail needs to be removed (been there) OR can the UIM/fuel rail just remain and the LIM be lifted off?
Thanks again.

I suspect that you will need to go in the same way you did before, but I am not that familiar with the L27. If the L27 uses the same plastic frame, silicone bead gasket between the LIM and UIM, I do know that these can be re-used if they have not been in service very long. So, at least that might save you $30. I'll go get you some L27 help. I checked my FSM for the '92 L27. If the same in '93, the lower can be pulled with the upper. Here is the procedure from the '92 FSM:

Remove or disconnect:

1. fuel injector sight shield and air intake duct
2. spark plug wires on right side of engine and set aside
3. fuel rail
4. exhaust crossover heat shield
5. cable bracket to cylinder head mounting bolt
6. power steering pump support bracket
7. loosen generator and move to obtain clearance
8. generator bracket
9. heater pipes
10. bypass hose
11. intake manifold bolts and manifold

For installation, use threadlocker on IM bolts and torque in sequence to 88-in-lb.

There are no hidden bolts on the L27 lower intake like on the L36, so yes, the LIM and UIM can be pulled together. Aluminum framed LIM gaskets are not available for the Series 1 motors, but aren't needed. S1 LIM gaskets look good enough to eat off for many miles, and don't have DEX screwing them up (or shouldn't).

The procedure above looks good. Consider taking the TB off and cleaning it after you get the manifolds off the car. Be warned that the TB is alot easier to remove from an L27 after the manifolds come out than on the car. The L27 is a finicky little bitch when it comes to the TB, and you may lose skin.

I've also run into an L27 that had the threaded anchors on the UIM inlet for the TB spin in place. If you can, back this up with a wrench on the back side of the inlet flange when you break the TB nuts/studs loose.

Torque specs are in Techinfo.

ONE MORE THING. Almost overlooked this.

On the accessory drive end of the LIM is a threaded barb fitting for the coolant bypass hose. If yours is original, it'* plastic. Go to the dealer and get a new one. They redesigned a few years ago to steel. Your plastic one has a limited lifetime and can dump coolant VERY quickly when (not if) it gives up. New part is cheap. Under ten bucks IIRC.

For the newer cars, this part would be similar in function to the Plastic Elbow on the S2. But this is a straight fitting threaded into the end of the LIM on the Series 1 cars.

Thanks guys. The procedure for pulling the LIM was spot on. Will, you were right about that bypass fitting, it was cracked and broke off the moment I tugged on the hose. Getting the remainder of it out of the manifold required some creative chiseling. I replaced w/ new metal fitting.My gaskets and seals appeared OK, but I replaced with new. The throttle body is a pain to get reinstalled, but I've just about got her all back together. Hopefully she'll fire up and go another 100K.
Great advice guys. I sure appreciate your help. Thanks a million.

Dropped the oil, it appeared OK. I could see some coolant, but did not have visible separation of oil and water (no milky froth). No metal shavings appeared when I ran a magnet thru it...I was concerned since the engine hydrolocked when it was idling for about 10 secs, engine was not under any real load, just idle, so that was a concern. After I put it all back together, it started on third try; idled rough, blew a lot of white smoke for 'bout 30 secs...idle improved. Shut down and re-started and let run for about 5 mins. Temp and oil pressure were good, white smoke lessened, idle steady. I've got a leak aound the thermostat housing to address, but other wise looks OK. I'm gonna do more through check for leaks, hopefully the thermo housing is only one.

Not wanting to appear too anal about this part, but we all believe that you should still do another oil change to ensure all that water is out of the oil. This comes from long experience on the club and is worth the $20 or so for oil and a filter to ensure long engine life.