Intake Plenum Assembly Meltdown-- Information Needed
02-14-2024, 08:32 PM
#11
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For Me, a Surprising Discovery
....
For what it'* worth, you can look on yours to see if the plenum that is on it now is a replacement or not. The production date codes are molded in the top. If this is your 1998 LeSabre (from your profile) that we're talking about, if the date shows 1999 or later, it is pretty much guaranteed to be a replacement and therefore possibly improved..
For what it'* worth, you can look on yours to see if the plenum that is on it now is a replacement or not. The production date codes are molded in the top. If this is your 1998 LeSabre (from your profile) that we're talking about, if the date shows 1999 or later, it is pretty much guaranteed to be a replacement and therefore possibly improved..
Thanks! This afternoon, after raising the hood for a closer look at the EGR and intake plenum, I noticed a faintly visible Dorman emblem, the product number 615-180, and below that the number 999. Apparently, the previous owner had the installed the Dorman intake plenum. The remaining issue is which version of the Dorman part was installed. According to one poster on another forumr, the Dorman part went through two modifications--. one to address the meltdown issue, and the other the explosion and fire issue. Not sure which Dorman plenum I have, though I searched all over the unit top surface for date codes, etc.
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CathedralCub (02-15-2024)
02-15-2024, 12:23 AM
#12
Senior Member
True Car Nut
================= My reply
Understood-- my preference is Delphi and Delco/Remy, also, whenever possible
================= My reply
VIN -- 1G4HP52K5WH500185
Buick 98 LeSabre Custom
Odometer 253,000
I am the third owner of this car, and until the immediately previous owner succumbed to his current wife, he had maintained good maintenance records. The aforementioned wife came upon the pile of his old Buick 98 maintenance records,and simply threw them out. That leaves me with an interesting voyage of discovery ahead.
Current projects include--
> replacinig the entire front brake assembly-- rotors, calipers and pads
> replacing the entire rear drum assembly
> replacing the EGR valve (the current EGR valve is still attached to its wiring harness, but nuts have been removed and the unit inverted, to leave it soaking in brake cleaner).
> replacing spark plugs and spark plug wires with a set rated for at least 100,000 miles
> preserving and protecting rubber and plastic body items, with UV-resistant products applied to surface
> inspecting suspension and steering parts and CV joints
Last fall, I replaced the battery and alternator, and plan periodic load checks and alternator output tests.
Plan to monitor oil consumption, as well as coolant, brake fluid and ATF levels.
Do you recommend I pull the transmission pan and filter and drain the fluid? No weird smells from the ATF, as of yet, and the pull-and-drain procedure may have been done more or less regularly by the next-to-previous owner.
I appreciate your interest!
Understood-- my preference is Delphi and Delco/Remy, also, whenever possible
================= My reply
VIN -- 1G4HP52K5WH500185
Buick 98 LeSabre Custom
Odometer 253,000
I am the third owner of this car, and until the immediately previous owner succumbed to his current wife, he had maintained good maintenance records. The aforementioned wife came upon the pile of his old Buick 98 maintenance records,and simply threw them out. That leaves me with an interesting voyage of discovery ahead.
Current projects include--
> replacinig the entire front brake assembly-- rotors, calipers and pads
> replacing the entire rear drum assembly
> replacing the EGR valve (the current EGR valve is still attached to its wiring harness, but nuts have been removed and the unit inverted, to leave it soaking in brake cleaner).
> replacing spark plugs and spark plug wires with a set rated for at least 100,000 miles
> preserving and protecting rubber and plastic body items, with UV-resistant products applied to surface
> inspecting suspension and steering parts and CV joints
Last fall, I replaced the battery and alternator, and plan periodic load checks and alternator output tests.
Plan to monitor oil consumption, as well as coolant, brake fluid and ATF levels.
Do you recommend I pull the transmission pan and filter and drain the fluid? No weird smells from the ATF, as of yet, and the pull-and-drain procedure may have been done more or less regularly by the next-to-previous owner.
I appreciate your interest!
I suggest you put these on your list:
- Change the belt if you have no idea how old it is
- Change the oil pressure sending unit (these commonly leak)
- Drop the transmission pan, clean it, change the transmission filter
- Check the front wheel bearings while you are fiddling with brakes
- If it lives in a hot area, think about putting a big transmission cooler on it
- If it lives in a hot area, think about putting a big power steering cooler on it
It has almost as many miles on it as my `97, that'* pretty rare these days!
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alphaa10 (02-16-2024)
02-15-2024, 12:25 AM
#13
Senior Member
True Car Nut
I can't fathom how they would fix the meltdown issue with any type of change to the plenum. That is caused by the fuel pressure regulator.
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alphaa10 (02-16-2024)
02-16-2024, 01:03 AM
#14
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That was the information I needed!
Until now, I read through dozens of comments (some from Dorman) about exactly what changes were introduced by the Dorman. Essentially, the Dorman product further "isolated" (word used by Dorman) the EGR hot gases from the plenum plastic, and in a way and to a degree the OEM plenum never did.
Compounding my information deficit, I read there may be more than one version of the Dorman UIM, which led me to wonder whether my recent purchase of the Dorman needed to be installed-- despite discovery of a possible earlier version, already in place.
And you have supplied the missing information-- that the Dorman modified product was not the primary solution to meltdown, but preventively replacing a faulty fuel pressure regulator.
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CathedralCub (02-17-2024)
02-16-2024, 02:20 AM
#15
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Thread Starter
Found This Fuel Pressure Regulator
This is the premium (better than OEM) version of the Delco fuel pressure regulator.
https://www.rockauto.com/en/moreinfo...t=6124&jsn=549
Does this meet the quality of the Delphi FP10016?
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CathedralCub (02-17-2024)
02-17-2024, 08:11 AM
#16
Senior Member
True Car Nut
=============== My reply
That was the information I needed!
Until now, I read through dozens of comments (some from Dorman) about exactly what changes were introduced by the Dorman. Essentially, the Dorman product further "isolated" (word used by Dorman) the EGR hot gases from the plenum plastic, and in a way and to a degree the OEM plenum never did.
Compounding my information deficit, I read there may be more than one version of the Dorman UIM, which led me to wonder whether my recent purchase of the Dorman needed to be installed-- despite discovery of a possible earlier version, already in place.
And you have supplied the missing information-- that the Dorman modified product was not the primary solution to meltdown, but preventively replacing a faulty fuel pressure regulator.
That was the information I needed!
Until now, I read through dozens of comments (some from Dorman) about exactly what changes were introduced by the Dorman. Essentially, the Dorman product further "isolated" (word used by Dorman) the EGR hot gases from the plenum plastic, and in a way and to a degree the OEM plenum never did.
Compounding my information deficit, I read there may be more than one version of the Dorman UIM, which led me to wonder whether my recent purchase of the Dorman needed to be installed-- despite discovery of a possible earlier version, already in place.
And you have supplied the missing information-- that the Dorman modified product was not the primary solution to meltdown, but preventively replacing a faulty fuel pressure regulator.
- "Meltdown": I am taking to mean the whole plenum on the 3800 Series 2 melts and/or catches fire to some degree. This is most commonly caused by a faulty fuel pressure regulator and solved by making sure, as much as possible, that the fuel pressure regulator is not defective.
- [EGR melting plenum plastic etc.] : This is related to the issue where exhaust gases in the EGR passage will melt their way to the coolant passage in the plastic plenum, allowing coolant to enter the combustion cycle and eventually damaging the engine or at least causing a no-start condition. This can be solved by adding a metal sleeve to the EGR passage and/or adding other features to prevent this melting. I have not personally read the Dorman write-up on how they do this, but doing what you described would likely solve it.
In short: If you want to prevent a fire and potential explosion and burning the car to the ground, keep the fuel pressure regulator in good shape. If you want to prevent the engine from being damaged and/or having a no-start condition from coolant entering the combustion cycle, keep the EGR passage in good shape.
Two separate issues in the same plenum.
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alphaa10 (02-17-2024)
02-17-2024, 08:14 AM
#17
Senior Member
True Car Nut
==================== My reply
This is the premium (better than OEM) version of the Delco fuel pressure regulator.
https://www.rockauto.com/en/moreinfo...t=6124&jsn=549
Does this meet the quality of the Delphi FP10016?
This is the premium (better than OEM) version of the Delco fuel pressure regulator.
https://www.rockauto.com/en/moreinfo...t=6124&jsn=549
Does this meet the quality of the Delphi FP10016?
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alphaa10 (02-17-2024)
02-17-2024, 06:10 PM
#18
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EGR Cleaning
... In short: If you want to prevent a fire and potential explosion and burning the car to the ground, keep the fuel pressure regulator in good shape. If you want to prevent the engine from being damaged and/or having a no-start condition from coolant entering the combustion cycle, keep the EGR passage in good shape..
Thanks for the summary, and in my efforts to finish this diagnostic and repair--
1. I have ordered (proactively) another fuel injector pressure regulator.
2. This afternoon, I attempted to remove, disassemble and scrub-clean the EGR, hoping clogged passages are the only problem. Unfortunately, I could not devise a way to take apart the EGR for a more thorough cleaning than simply squirting throttle body cleaner into both passages. Is it possible to disassemble an EGR for this GM engine? I found one TORX-type screw on the bottom-center, which seemed to be spring-loaded, but which simply rotated, and did not unscrew. And where two bolts appeared to pass through the EGR body, there was no visible opening for a nut or bolt head on either side of the body.
I appreciate your working on this with me-- I run a service business, too, and there is so little time for anything.
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CathedralCub (02-17-2024)
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CathedralCub (02-17-2024)