98 buick lesabre upper and lower intake

[wyattearp29]

lots of good info . I was just wondering if somone had a detailed procedure. I tried the maint section but it would't work.

[Hapynzap]

autozone has online help

http://www.autozone.com/shopping/rep...00c152800b1c9a

[BNaylor]

I would be careful posting or recommending Autozone Repair Info without properly reviewing it for correctness, accuracy or discrepancies.

Note: In the Autozone repair info help the upper intake plenum (UIM) and LIM bolt torque figures are incorrect for the VIN "K" SII 3800 engine.

The UIM bolts are 89 in-lb and the LIM bolts 11 lb-ft or 132 in-lb.

Also, the instructions are very vague in removing the tensioner assembly as part of the LIM job and omits the procedure for removing the two coolant bypass elbows from the water pump and LIM. See the Buick Tips & Maintenance section for a tech procedure. See link.

Tensioner Assembly Removal for SII 3800 Engine and Bypass Elbows


The pic below shows LIM gaskets properly installed with bead of hi-temp silicone sealant at the 4 corners where the LIM port gaskets meet the end seals. The gaskets shown are the pinned FelPro brand. Let the silicone sealant cure for approximately 24 hours before firing up the engine upon completion of the job.

[wyattearp29]

So I should plan on replacing the bypass elbows? Also how common is it for the bottom manifold gaskets to go bad. It sounds alot more common for the upper intake to fail.

[BNaylor]

When the tensioner is removed high probability they will break or you will find them deteriorated so best to replace them along with the two o-ring seals on each.

LIM gasket failures are just as common as UIM plenum and UIM gasket so it is best to replace it all.

What are your current symptoms or what indicators do you have that warrant this type of job?

And welcome to AF.

[Smith1000]

When the LIM goes out, does it typically leak into the engine, or on the outside? I noticed my white 97 Lesabre is again losing coolant (internally). I repaired the UIM with a kit years ago. It has 205k on it now and possibly needs the lower and upper (again). When it went out years ago, it leaked both inside and out. It was burned around the egr passage stovepipe.

I replaced the gasket and UIM in our other Lesabre last summer. It had a bad/broken gasket. I believe it had been over tightened when the job was previously performed.

[BNaylor]

Originally Posted by Smith1000

When the LIM goes out, does it typically leak into the engine, or on the outside?

For LIM gaskets both scenarios but the one of concern obviously is the internal leaking and unexplained coolant consumption. The older GM LIM plastic framed gaskets are garbage compared to the revised GM aluminum framed and plastic ones put out by FelPro.

The LIM gaskets in the pic were bad enough to cause some coolant to be consumed in combustion. Luckily it eventually triggered the SES/CEL light with a MAP sensor DTC and the PCV valve and channel in the UIM had obvious signs of coolant. It turned out the LIM port gasket on bank 1, cylinder 1 was the worse. Upon closer examination coolant and steam were being slowly pumped into the crankcase. There was coolant residue/condensation on the back of the oil filler cap and combustion by-products in the cooling system (sludge formed).

[jbjslambert]

someone does have a complete procedure posted on the internet somewhere i have seen it, i thought it was here but i guess not. i will look for it and post a link if i find it. joe

you can go down into the post a little and find some pics i posted, just shows what i found when i opened it up though.

its pretty easy job to do, better to take off throttle body along with the UIM due to placement of bolts that are hard to get to. if need help start another post asking for procedure help and alot of people wil help you out.

[wyattearp29]

My syptoms are I am losing coolant and I can't figure out where it is going. I noticed about a year ago but lately it is getting worse. the other day it through a misfire code so I started to research and that is what led me to upper intake problem.

[BNaylor]

Unless there is obvious external coolant leaks then your assumption you have either a UIM or LIM issue and internal leak causing the coolant loss is probably correct. I would not wait too long to get this job done. If it gets worse you can hydro-lock the engine or any coolant contamination in the crankcase will damage the internal engine components like the pistons/rings, block, camshaft, connecting rod and crank bearings and the valvetrain.

[wyattearp29]

Hey bnaylor can you send me the pdf that you have. The ones under the maint section won't work.

[maxwedge]

Just to add some advice here, use sealer on the 2 corner inside lower intake bolts, oil can migrate up the threads causing oil consumption.

[BNaylor]

Originally Posted by wyattearp29

Hey bnaylor can you send me the pdf that you have.

Sure not a problem. Just send me a PM message with a regular email address so I can send it as an attachment.

[Buc1]

Hey bnaylor can you send me the pdf that you have.97 buick lesabre upper and lower intake Thanks

[BNaylor]

Originally Posted by Buc1

Hey bnaylor can you send me the pdf that you have.97 buick lesabre upper and lower intake Thanks

Welcome to AF and the forum.

No problem. File sent to your email address which I will edit out to protect you from spammers picking up on it.

Good luck and lets us know how it turns out.