Coolant leak 2002 Grand Prix GT W/3800

[johnwon454]

Hi; I've read a lot about the UIM & LIM leaks and am confused as to what mine is most likely to need. I smell a strong coolant odor when the car is first pulled into the garage. I've added only about a half a gallon to the overflow tank in about 6,700 miles "mostly short trips from 2 to 14 miles at a time" and this is over a 10 month period. I've removed the plastic top cover to try and see some sort of leak. All I can see is some damp spots on the heads "drivers side" no puddles anywhere on engine or garge floor. I bought the car in Feb. 06 from a sales rep who drove a lot of highway miles...it had 110,000 when I bought it and now has 117,000. I've read here on at least one thread from a service bulletin that the intake is not necessary to replace but another states that a new GM one is available. Also if I should put a new upper intake on it...should I go with the new GM unit or a good after market. My local mechanic said he uses after market on all of the ones he does. I may lean to aftermarket too, just not to reward GM anymore of my money due to something they should have taken care of. Is there any after market units that I should stay away from? , if it turns out it should be replaced??
PS There is no sign of coolant in the oil yet...no milky film. Thanks for any help in what a 2002 should or should not need.

[GTP Dad]

Welcome to AF!!

With the mileage you state you could be living on borrowed time with these gaskets. I really don't think that the gaskets are the issue at the present time as you aren't really experiencing the symptoms of a gasket issue. I would check the car in the areas of the radiator, hose connections, thermostat housing and any areas where you may have hoses. The amount of coolant you indicate you are going through indicates you have an issue somewhere but it may be hard to track down.

One thing you can try is to have the system pressure tested. A pressure test shoulds show any leaks that you may be experiencing especially if you put the flourescent dye in the system.

As for the upper intake, use the aftermarket although GM did redesign and improve on the OEM one.

[johnwon454]

Thanks GTP DAD. I did some research on the GM intakes and to my understanding they introduced a new design gasket set in May of 2006 and a new upper intake in June of 2006. With this being the latest, would this be a better choice over after market? My local mechanic said he use "Motormite" as for the after market he normally installs. Any of you know anything about the quality of these units? As for the leak...I'm thinking it's going to need it sooner or later anyway. I just want to make the best choice in parts even if it means buying GM. Thanks for all and any help!!

[richtazz]

GM revised the upper plenum in late 99, that addressed the commom EGR stovepipe failure on early 99-older Vin-K 3800's. The problem is that they still used the same JUNK gasket. If you see no external leaks, or if it has a small leak from the throttle body area (dirver's side), then it's most likely an upper plenum gasket failure, not a bad plenum. Another common coolant leak issue on the Vin-K 3800 is the plastic elbows that go from the intake to the belt tensioner on the passenger side. They get brittle with age, and will begin leaking only under pressure, then get progressively worse. At first, they will not leak enough to get on the ground, but you will smell coolant under the hood. The other leak area is the water pump casting. When the bearing seals fail, they will leak coolant out the "weep hole" and again, it will start as such a small leak, you may not see it on the ground.

[BNaylor]

Originally Posted by johnwon454

I did some research on the GM intakes and to my understanding they introduced a new design gasket set in May of 2006 and a new upper intake in June of 2006. Thanks for all and any help!!

If you are referring to the new GM aluminum style lower intake manifold gaskets out around May of this year for the SII 3800 that is true. We have one member that has used them.

Other companies that make the UIM plenum are Dorman and Ken-Co.

[johnwon454]

Originally Posted by bnaylor

If you are referring to the new GM aluminum style lower intake manifold gaskets out around May of this year for the SII 3800 that is true. We have one member that has used them.

Other companies that make the UIM plenum are Dorman and Ken-Co.

Hi: I guess I thought the lady I talked to at our local GM parts Department was talking about the UIM gaskets. Thanks for getting me straight on that.

[johnwon454]

Originally Posted by richtazz

GM revised the upper plenum in late 99, that addressed the commom EGR stovepipe failure on early 99-older Vin-K 3800's. The problem is that they still used the same JUNK gasket. If you see no external leaks, or if it has a small leak from the throttle body area (dirver's side), then it's most likely an upper plenum gasket failure, not a bad plenum. Another common coolant leak issue on the Vin-K 3800 is the plastic elbows that go from the intake to the belt tensioner on the passenger side. They get brittle with age, and will begin leaking only under pressure, then get progressively worse. At first, they will not leak enough to get on the ground, but you will smell coolant under the hood. The other leak area is the water pump casting. When the bearing seals fail, they will leak coolant out the "weep hole" and again, it will start as such a small leak, you may not see it on the ground.

Hi: That is good to know...I may not need a new UIM. Is it safe to say that a 2002 Grand Prix GT with 3800 series II most likely will not need a replacement UIM??? Thanks

[richtazz]

yes, but inspect it when it is torn down, as a gasket let go too long can damage the upper plenum. Also, the Dorman aftermarket plenum is a pretty nice unit if you end up needing one (and for those reading this with 99-prior engines).

[maxwedge]

That Dorman manifold literature claims it fits 95-2003 at least.

[BNaylor]

Originally Posted by maxwedge

That Dorman manifold literature claims it fits 95-2003 at least.

As it pertains to the Series II 3800 engine, in general, that is true, especially the 95 - 96 model years. However, the Dorman Vin "K" UIM is only applicable to 97 - 03 model Grand Prixs since both the 95 and 96 Grand Prixs were never delivered with the SII 3800 only the 3.1L and 3.4L engines.

However, GM did first introduce the SII 3800 Vin "K" in 1995 in Pontiac Bonnevilles, Buick Riviera, Buick Park Avenue and the Olds 88s. GM "W" bodies like the Regal first received the SII 3800 in 1996.

Just wanted to clarify that.



BTW - I believe Rich was referring to any pre - 1999 GP owner that may read this thread because those year models had the flaky UIM plenum with the EGR stovepipe meltdown problem. Specifically 97 - 98.

[johnwon454]

Thanks for the info, y'all are a good bunch!
As for the LIM gaskets....which years is this an issue for the 3800 Series II ?? Or more specifically are they also a known problem to the 2002 model year?? Thanks again.

[BNaylor]

Originally Posted by johnwon454

Thanks for the info, y'all are a good bunch!
As for the LIM gaskets....which years is this an issue for the 3800 Series II ?? Or more specifically are they also a known problem to the 2002 model year?? Thanks again.

Here are two applicable GM TSBs which address the issue on later model Grand Prixs with the SII 3800 Vin "K". According to the second TSB new UIM gaskets were made available around May 2004.

Therefore, no 1997 - 2003 model Grand Prix with Vin 'K" is immune to UIM and LIM problems.


File In Section: 06 - Engine/Propulsion System

Bulletin No.: 03-06-01-016

Date: May, 2003

TECHNICAL

Subject:
Loss of Coolant, Milky Colored Oil
(Replace Intermediate Intake Gasket)


Models:

2000-2003 Buick LeSabre, Park Avenue, Regal
2000-2003 Chevrolet Impala, Monte Carlo
2000-2003 Pontiac Bonneville
2000-2003 Pontiac Grand Prix
with 3.8L V6 Engine (VIN K - RPO L36)

Built Prior to the VIN Breakpoints shown.

Condition

Some owners may comment on a loss of coolant, coolant odor, having to add coolant or a milky substance on either the oil dipstick or oil fill cap. Additionally, owners may indicate that there are signs of coolant loss left on the ground where the vehicle is normally parked.

Cause

Condition may be due to coolant leaking past intermediate intake or throttle body gaskets.

Correction

Important: The upper intake manifold should not be replaced for a coolant leak condition, unless a rare instance of physical damage is found. Even if the throttle body surface shows a slight warpage, the upper intake should not be replaced unless a drivability concern is noted or a relevant engine DTC, such as a code for an unmetered air leak, is set and the upper intake manifold can clearly be shown as the cause of the concern.


Thoroughly check for any external leaks. If no external leaks are found, then replace the intermediate intake manifold gasket and the throttle body gasket. When changing the throttle body gasket, the nuts that retain the throttle body should be replaced with a new design that improves torque retention. Medium strength thread locker should be applied to the studs before installing the new nuts.

Parts Information

Parts are currently available from GMSPO.

__________________________________________________ ______________

Bulletin No.: 04-06-01-017

Date: May 26, 2004

INFORMATION

Subject:
New Upper Intake Manifold and Gasket Kits


Models:
1995-1997 Buick Riviera
1995-2004 Buick Park Avenue
1996-2004 Buick Regal
1997-2004 Buick LeSabre
1998-1999 Chevrolet Lumina
1998-2004 Chevrolet Monte Carlo
2000-2004 Chevrolet Impala
1995-1996 Oldsmobile Ninety-Eight
1995-1999 Oldsmobile Eighty-Eight
1998-1999 Oldsmobile Intrigue
1995-2004 Pontiac Bonneville
1997-2003 Pontiac Grand Prix
with 3.8L V6 Engine (VIN K - RPO L36)


New upper intake manifold and gasket kits have been released. These new kits will provide the dealer with the ability to get exactly what is necessary for a correct repair. In addition some of the gaskets have been updated to a more robust design. Please reference the part numbers when ordering from GMSPO.

[johnwon454]

Thanks bnaylor for your in put on this subject.
Would anyone care to share the symptons of the LIM gasket leak?? Thanks

[handyman76]

richtazz, you mention the elbows on the passenger side of the 3800 engine. Do you happen to know the name of these parts or where I might find them mentioned in a Haynes manual? I've been tracking down coolant leaks for over 3 years on my 2001 3800. It's been reliable, but I've already replaced the upper intake and I still have what appear to be very small leaks around these elbows. I'm hoping the parts are available from outside GM, but I don't feel confident in asking an autoparts place because they tend to not hire the most knowledgeable people. I need to get this fixed because my wife driving the truck to work and getting 9mpg is killing my budget!