15th Feb 2009, 05:18

My dad purchased a 98 Buick Le Sabre with 98,000 miles on it. Within a month he started losing coolant and had white smoke coming out of the tailpipe. The engine quit running and the starter went out. After talking to the dealer he was informed the plastic plenum on the 3800 motor were prone to go bad. He was able to use Bars stop leak and has driven another 2000 miles with no further problem. So far so good. If anyone wants to try this before making a major repair make sure to follow all instructions on stop leak bottle to the letter. Change plugs and oil and give it a shot. Hope this helps.

2nd Mar 2009, 08:51

Simply adding Barrs Leak is asking for trouble. The upper intake plenum must be replaced with the newer design plenum. I just did this on my 98 Le Sabre. It takes about 4.5 hours for someone with good mechanical skills. You must torque the plenum bolts down to the proper torque specifications with a torque wrench. ***Very Important Note***: If your vehicle has the automatic climate control A/C heater controls, you MUST turn the HVAC system off before beginning the plenum replacement or you will cause damage to the A/C heater control system.

19th Jun 2009, 16:41

Well I am a new member as well, filled it up with coolant, and let it sit for 2 hours, came out to crank it up and vapor lock. Towed the car to the shop, starter teeth were worn down and the cup was cracked off, front three plugs fouled, they were full of coolant!

19th Jul 2009, 10:50

EGR valve is probably clogged up. Possible need to clean the pintle inside. Or it could be caused by a weak coil. Which happened in my case and the side effect was that it clogged the EGR valve up.

24th Aug 2009, 14:56

Same thing recently happened to our 1998 Buick Century.

Drove it just a few miles when out of nowhere the check engine light came on. Stopped, shut it off, waited 30 minutes and checked the coolant, and sure enough it was low.

I added some more, and it fired right up with no problem, drove it home and about a tenth of a mile from my home, the light came back on and it started heating up quickly.

Got it into the driveway, the fans were working so I shut it off.

After cooling I checked the coolant and yet again it was indeed low again.

It has been parked since, I did purchase the thermo gasket ($150.00+) but I have not used it as I'm fearing that it may lock up before the system gets flushed, thus further damage such as vapor lock etc.

I think this was a test of which would be better effective, some Buicks used the plastic which failed, while others the head gasket cover was a different metal than the engine, causing an acidic reaction which destroys the gasket, causing the coolant to leak into the engine.

Neither one of the types are workable or fair.

There should have been a re-call long ago, and all the head gasket covers replaced with aluminum covers.

14th May 2010, 14:32

I had my intake manifold replaced a few years ago and the mechanic put a metal sleeve in one area of it (sorry I know nothing about cars). He said it shouldn't happen again. Today on my way home the engine started running rough and the temp gauge went up to the red mark. There isn't any antifreeze in the reservoir at all. I am afraid it's the intake manifold again.

LeSabres are infamous for this. So I am told.

5th Jun 2010, 10:47

I'm facing this problem right now on a 1999 LeSabre with only 36,000 miles on it. Same symptoms, engine light on, loss of power, rough idle except no white smoke or loss of coolant. Engine also would not re-start. Is there a sure way to pinpoint the plenum or gasket as the main problem? Thanks.

29th Jun 2010, 02:45

I just had to have my intake manifold replaced. My Dad had it replaced about 2 and a half years ago, so this time I had an aftermarket intake put on.

30th Jul 2010, 13:33

Hello new friends. I have just been inducted. We have a 1999 Oldsmobile 88 with the 3800 P2 engine. It recently hit 68,000 miles.

Today when my wife was driving on the highway, the check engine light came on and she noticed it was beginning to get hot. She turned around to come home, and made it home before the car overheated completely. I noticed right away that the coolant reservoir was empty, because I had just filled it the night before. I opened the radiator cap and the radiator was bone dry. My initial thought was that the radiator cap was malfunctioning and allowing the coolant to steam out when it was warm. I ran the car for a good long while to see if I could see the problem. After about 20 minutes, I shut the car off to take a break for a while. When I came back out, roughly 30 minutes later, the car wouldn't start. It would turn over, but not start. I tried again, and felt the starter struggle, so I quit trying to start it.

I called my buddy who runs an auto repair shop, and before I could finish telling him what had happened he said "You have an Oldsmobile, right?" I told him yes, and he explained the plastic manifold problem. I had it towed into his shop where it was confirmed. I have had this car since it was brand new, and haven't had any problems with it at all. I always keep it maintained, and was hoping for a couple more years of trouble free service. Now I just hope I get a couple more years out of it.

My buddy is still figuring up what the bill is going to be, but by looking at these posts, I am going to prepare myself for a 1000 to 2000 bill. This sucks.

I currently have a 2004 Ford Freestar van with 72,000 in the shop getting a transmission 3k+. This is the first I have heard about this issue. I am glad I found some information on it.