1998 Lumina LTZ - 3800 engine

[77_Vette]

Hi !

I drive a 1998 Chev Lumina LTZ with the 3.8 engine and has 90,000 miles on it..

2 weeks ago I noticed it starting to lose coolant from the reservoir tank. Once per week (300 mile) the reservoir tank was empty. There were no signs of leaking under the car. There was also no sign of water in the oil or oil in the water, and the car runs normal.

I took it to a mechanic friend who thought it was the water pump. He pressure tested everything and there were no problems. He replaced the water pump just in case. This was not the problem as the leak continued at the same rate. I then added ‘Bar Leaks’ to the coolant. Again, the coolant lose was the same.

I then went to my local GM garage. Once again they pressure tested everything. They also did a ‘dye & black light test’ and found no fluid problems. After extensive testing, they decided that perhaps the rad cap was faulty so they replaced it. Guess what – one week later, the coolant lose is still the same, and I’ve pumped almost $400 into this car over the past 2 weeks.

Can anybody help with this one ????

Many thanks in advance

[KC Ron Carter]

That coolant is going somewhere.

I would suggest visualling the cylinders or sparkplugs at least and look for a very clean one. I will suggest that the plastic intake has been know to leak coolant into the cylinder.

It usually gets bad enough to cause a liquid lock.

Later,

[GMMerlin]

The 3800 series engines are known to leak coolant internally at the area where the egr tube goes into the plastic plenum.
A pressure test would have showed a loss of pressure (even though you would not have seen any coolant loss)
Also look at the area under the throttle body where the upper and lower intakes meet..you may see some dry white trails where some coolant has leaked out.

[77_Vette]

KC RON CARTER: Many thanks for the reply. I researched further about your advice and there is a view on the internet that the upper manifold gasket may be the culprit as the gasket is made of plastic and/or had a high plastic content when originally installed. Apparantly the replacment gasket has less plastic now. When I spoke to both my mechaninc friend and my service advisor about this possibility, they both stated that they didn't think that would be the problem as the pressure test showed no loss of pressure, and that there wasn't oil in the water or water in the oil. My GM service advisor did quote me $800 to replace this !!!!!

GMMERLIN: I'm a little confused by your reply - sorry it's Saturday morning ! As I noted above, when the pressure test was done both by my mechanic friend and GM garage there wasn't any loss pf pressure in the system. In your opinion does this rule out the manifold gasket? Does it also rule out where "egr tube goes into the plastic plenum". Where is this on the car ? Is this something I can look for or replace myself ? As well, would a pressure test have failed if there was a coolant under the throttle body where the upper and lower intakes meet. Where can I find this on the engine ?

To both of you: I had it recommended to by another friend not to worry about it as the reservoir tank is just that. If it goes down, no big deal as it goes up and down all the time as what matters is the fluid level in the rad. I was advised to wait and see if it overheats. I'm not so sure about this answer. Isn't the point of the reservoir tank also for the cooling system to draw in coolant if there is a loss. This advice makes me nervous. You opinoin ??

Thanks for the replies folks !

[KC Ron Carter]

on a steel block.

All with different expansion rates.

The fluid is going somewhere.

If not external is is being consumed by the engine.

It will only get worse, and if it overheats it will destroy the engine.

Later,

[Ken Spragg]

I have a company in Burlington who has manufactured a fix for this problem. If you PM me I will give you the particulars. You can email me at [email protected]

[GMMerlin]

This should answer your question.
Cooling leaks can be difficult to find under a pressure test. The expansion and contraction rates of the different types of materials can hide or present a leak. While checking a vehicle under pressure, I check with the engine both cold and at operating temperature...also I look for trails or unusual clean spots that may indicate there was a leak present.
Here is a copy of the GM tech bulletin that applies to your vehicle...this is a repair bulletin...not a campaign or warranty repair



Engine Coolant Consumption or Coolant Leak (Inspect for Material Degradation/Replace Intake Manifolds) #01-06-01-007A - (07/18/2001)
Engine Coolant Consumption or Coolant Leak (Inspect For Material Degradation/Replace Intake Manifolds)
1995-1997 Buick Riviera

1995-1998 Buick LeSabre, Park Avenue

1996-1998 Buick Regal

1998 Chevrolet Lumina, Monte Carlo

1995-1996 Oldsmobile Ninety-Eight

1995-1998 Oldsmobile Eighty-Eight

1998 Oldsmobile Intrigue

1995-1998 Pontiac Bonneville

1997-1998 Pontiac Grand Prix

with 3.8 L Engine (VIN K -- RPO L36)

This bulletin is being revised to correct parts and labor operation usage. Please discard Corporate Bulletin Number 01-06-01-007 (Section 6 - Engine).

Condition
Some owners may comment on excessive engine coolant consumption, or an engine coolant leak near or under the throttle body area of the upper intake manifold.

Cause
Upper intake manifold composite material may degrade around the EGR stove pipe and could result in an internal or external coolant leak.

Correction
Follow the upper intake manifold removal instructions found in the Engine Unit Repair Section of the Service Information Manual.



Refer to the arrow in the illustration of the upper intake manifold above. Inspect the inner diameter of the EGR passage for signs of material degradation. Degradation will appear as "pitting" of the composite material in the EGR port passage.
If degradation of upper intake manifold composite material is found, replace the lower and upper intake manifolds with the following part numbers:
Lower Intake -- 24508923
Upper Intake -- 17113136 (includes necessary upper intake plenum gaskets)
Lower Intake Gasket -- 12537197
Follow the lower and upper intake manifold installation instructions found in the Engine Unit Repair Section of the appropriate Service Manual.
If degradation is not apparent, skip to Step 7.
Verify the repair.
If no degradation is found, evaluate the vehicle for other causes of excessive coolant consumption as noted in the Engine Diagnosis Section of the appropriate Service Manual.

[Ken Spragg]

Thanks to "Flatrater" (our moderator).

He has allowed me to post the information on my web site detailing the information on repairing the 1995-up 3800 k series engines intake manifold EGR tube and upper manifold degradation.

The fix is quite easy. I have developed a product to repair
both sides of the problem. The problem is that the lower
manifold heats and degrades the "plastic" in the upper
plenum. The OE fix is expensive, but does fix the problem.
The repair at the OE level runs about $1400 - $1800 if it
is done properly. A lot of the money is in the parts. The
upper and lower manifolds can range upwards of $600.00 at
retail.

Our fix stills has to have the lower manifold exposed, but
not removed. Simply remove the old EGR tube (pulls out with
vice grips) and reinstall our new one. We supply for the
upper plenum a sleeve and epoxy to repair the degraded
plastic. The new fix allows for cooling between the new EGR
tube and the plenum resulting in less retained heat. Use an
OE gasket during this repair to complete the job. The
information can be found at (http://www.ken-co.com/manifold or by emailing me at [email protected]
[mailto]. Stock is available in the U.S. Email me and I'll
direct you to the U.S. source.

Ken Spragg

[77_Vette]

To all that have answered, my sincere THANKS for all your opinions. Since I posted things got WORSE !!!!!!!!!!!

I brought the car back to the GM garage a little angry ! I spent $293.05 to have the rad cap replaced, but the problem got worse when I saw a leak under the car on Monday. By the the time I drove it to the dealership (about 5 minutes from my house), and turned the car off, it wouldn't start - guess what - hydro-locked !!!!!!!!!!!!!

It turns out their diagnosis was wrong and that the #2 cylinder was full of coolant - non of it in the oil. The problem = headgasket.

I picked the car up tonight a little poorer: $1,456.03 later !!!!!!!!!

They had to installed the headgasket kit (GM part 17113137) consisting of a headgasket, spark plugs, thermostat, manifold gasket, etc. etc.

So all along it was the head gasket. My GM garage said this was a rare event for the 3800 which is considered "bullet-proof". The gasket kit had to be shipped from a GM dealership in Michigan, as there was none in Canada.

It wasn't so bad, if I didn't have to take it back again. Besides not hooking up my cruise control, the engine sounds like a bucket of bolts, and there is a distinctive 'ticking' sound comming from it. It's back at the garage tonight and see what is going on.

I've owned GM products all my life - I'm seriously reconsidering after this fiasco.

My next question: Did the hyrdo-locking mess up my engine ???????

Dwight.