Mechanics

CARPRO TECH ,QUESTION

1997 Buick Lesabre

Engine Performance problem
1997 Buick Lesabre 6 cyl Front Wheel Drive Automatic 180 miles

Hi. I have a prob with this old lesabre I picked up for one of my kids to drive. And so far am stumped.
this car has a series 2 3800. The engine overheated and would not start. After doing a lot of diag I found.
fuel pressure 45psi
spark good spark at all plugs
injector pulse on all inj.
removed inj and all have perfect spray pattern
compression 120 on all cyl
no blown fuses
.

removed timeing cover timeing gears fine.
new crank sensor and cam sensor.


only code showed up on mt 2500 no cam signal

exhaust is not plugged

removed plantum intake chamber full of oily anti
replaced plantum gasket.
car started and ran fine.


until we put coolant in, then died same thing cranks and no start. No water in the oil.


do you think the intake gasket could be blown and internally leaking into the conbustion chamber.


this is the only logical explanation I can come up with
for the oil and coolant under the plantum.

well any help would be appriciated. Thanks billymac
Avatar
Billymac
July 29, 2009.




The coolant in the intake is from the EGR passage being rotten, letting coolant into the upper plenum. If you remove the upper and turn it over, you will see it rotten where the EGR gasses go through it. Common for those engines

Tiny
Jack42
Aug 3, 2009.
Hi Jack
Yes you are exactly right. The funny thing is I removed the plantum and dissassembled, and shined a light inside exhaust port. But was unable to find the leak. However after reading your post I checked again and just minor pressure with a ink pen revealed
pin hole. Anyway I really appriciate your help.

Billymac

Billymac
Aug 3, 2009.
Anytime. Funny thing is I had the exact same thing on the rack at the same time. Quite a coincidince

Tiny
Jack42
Aug 3, 2009.
This was a common problem on these, had alot of these. Replace the upper and lower intake, not just the gaskets, but the actual intake upper and lower. There is an updated intake and plentum. What happens is the egr port under the plentum is to big and burns the intake port and causes coolant to leak into the egr port and into the engine. Here is the bulletin, Some customers 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: " Gasket Kit, Upper Intake Manifold -- 89017554

" Manifold Kit, Upper Intake -- 89017272

" Gasket, Lower Intake Manifold -- 89017400

" Manifold, Lower Intake -- 24508923

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.
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2Carpros Max
Jul 16, 2013.

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