Second UIM/LIM failure, EGR question - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 08-28-2008, 01:25 PM   #1
Junior Member
Thread Starter
 
Join Date: Aug 2008
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
gm98 is on a distinguished road
Default Second UIM/LIM failure, EGR question

My '98 Bonne had its first failure at ~70,000 miles. The plenum was badly fried: it looked like burnt sugar near the EGR pipe. Upper gasket failed. The mechanic replaced the plenum, upper and lower gaskets with aftermarket parts of unknown brand.

Second failure was a month ago ~90,000 miles. This time it was a lower gasket. The plenum was again melted and visibly deformed near the EGR pipe.

I have a new mechanic now... he drives and repairs race cars, and owns 7 GM cars himself. (One'* a Bonne with more miles than mine, which has never had UIM/LIM issues.) He swears by OEM parts.

I found out about GM'* redesigned LIM gasket (with the aluminum frame) on one of your forums... THANK YOU! We installed two of these new gaskets, also upper gasket and a new plenum... all OEM parts.

My mechanic acknowledges there is a heat problem around the EGR pipe, but does not want to talk aftermarket parts, hence no reduced diameter stovepipe.

Here are a few questions:

(1.) Why do some of these 3800'* fail early and/or repeatedly, while others seem to run "forever"? Has anyone figured this out?

(2.) Is there any way to go back to a metal plenum on this engine? Why or why not? Would that be a good thing?

(3.) What'* the reason for the EGR system? What would happen if the EGR plumbing were plugged/blocked, so no hot exhaust gas ever went up through that EGR pipe (thus protecting the plenum from heat)? What would be the effect on efficiency, performance, etc.? Might this cause other problems with the engine at a later time? Would the engine computer compensate by adjusting the mix, timing, or whatever?

THANKS IN ADVANCE for any further information.
gm98 is offline   Reply With Quote
Old 08-28-2008, 03:33 PM   #2
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

This thread is extremely good reading. Mkaake works for GM directly. He is the guy with the inside track on most things and was able to share this one with us.

https://www.gmforum.com/t265590/?highlight=holes

For GM to retool or rework after production was halted is a big thing. Couple the lack of coolant in the upper with the aluminum gaskets and I think it may be a great motor.

Personally I've plugged three L36 upper manifolds, the first was approximately 6-7 months back with all running great.
BillBoost37 is offline   Reply With Quote
Old 08-28-2008, 03:42 PM   #3
Village Idiot
Posts like a Turbo
 
Join Date: May 2007
Posts: 280
Thanks: 0
Thanked 0 Times in 0 Posts
iluvmybonnie is on a distinguished road
Default

blocking the egr will net you a few HP probably but you'll also probably throw a code. if you want to learn more about EGRs etc try searching on google. EGR deletes are very popular on many cars.
iluvmybonnie is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
UIM and LIM replaced now leaking coolant out of UIM gasket Paul1981 2000-2005 10 12-21-2007 11:05 PM
is this LIM/UIM gasket failure? grey3800 1992-1999 5 10-19-2007 06:40 PM
2nd possible lim/uim failure BIchselmnop 2000-2005 3 03-20-2007 01:39 AM
What are the early signs of UIM/LIM failure? two bonnies 1992-1999 11 02-25-2007 03:14 PM
Just a Gen question about S2 LIM & UIM bandit General GM Chat 5 12-27-2006 12:05 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:57 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.