3800 intake coolant leak 95 Trans Sport

with the 3800 Series II. I have also looked at the info at

and the following pages of that site. I believe the info there was in regard to a 1998.

coolant leaking out from under the upper intake plenum under the throttle body, or it could be leaking from the throttle body to plenum connection. Actually, it appears to be both. But my design is not the same as shown in the above web site. My EGR is a pipe off the exhaust manifold and into the side of the plenum behind the throttle body. I don't see deterioration of the plenum since I have torn it down. Any ideas on what my problem is? And why the different design on the EGR/plenum? Thanks, Marv

Well for starters, here's a copy of the actual GM TSB that I've posted on my own forum:

well as here's a cheaper fix for you to consider too. I sell this repairkit from my own store.http://www.bonnevilleattitude.com/store/product_info.php?products_id=701Any questions you have regarding any of the options above please ask me.

Thanks for the reply. I looked at the links you gave, but they do not apply to my situation. I do not have the EGR running up through the manifold, but rather into the side of the manifold behind the throttle body. The GM # for my upper plenum is 17113044. The GM partsman is saying replace the entire plenum - that the plenum was updated with thicker walls to prevent cracking and warping. He has no notes or alerts on the part number when he looks it up, however. I noticed the list on the TSB does not include the 95 Trans Sport. So did my plenum have a problem and was it actually updated? The part number has remained the same. Thanks again, Marv

the 3800 Series II. I have also looked at the info at

and the following pages of that site. I believe the info there was in regard to a 1998.

coolant leaking out from under the upper intake plenum under the throttle body, or it could be leaking from the throttle body to plenum connection. Actually, it appears to be both. But my design is not the same as shown in the above web site. My EGR is a pipe off the exhaust manifold and into the side of the plenum behind the throttle body. I don't see deterioration of the plenum since I have torn it down. Any ideas on what my problem is? And why the different design on the EGR/plenum? Thanks, Marv

I have pics of my engine I would be glad to email you. Email me at snipped-for-privacy@netzero.net and I will get them to you. Thanks, Marv

I have pics of my engine I would be glad to email you. Email me at snipped-for-privacy@netzero.net and I will get them to you. Thanks, Marv

"jmh" wrote

coolant leaking out from under the upper intake plenum under the throttle body, or it could be leaking from the throttle body to plenum connection. Actually, it appears to be both. But my design is not the same as shown in the above web site. My EGR is a pipe off the exhaust manifold and into the side of the plenum behind the throttle body. I don't see deterioration of the plenum since I have torn it down. Any ideas on what my problem is? And why the different design on the EGR/plenum? Thanks, Marv

Your engine does not have the same problem that affects the Gen II engine, but that doesn't mean that those plastic intakes on the older version didn't occasionally leak. Best to just replace the upper plenum.

Ian

apply to my situation. I do not have the EGR running up through the manifold, but rather into the side of the manifold behind the throttle body. The GM # for my upper plenum is 17113044. The GM partsman is saying replace the entire plenum - that the plenum was updated with thicker walls to prevent cracking and warping. He has no notes or alerts on the part number when he looks it up, however. I noticed the list on the TSB does not include the 95 Trans Sport. So did my plenum have a problem and was it actually updated? The part number has remained the same. Thanks again, Marv

Try this TSB then:

COOLANT LEAK NEAR THE THROTTLE BODY #57-61-04 - (04/25/1995) SUBJECT: COOLANT LEAK NEAR THE THROTTLE BODY (REPLACE THROTTLE BODY SEAL)

MODELS: 1993-95 BUICK LESABRE, PARK AVENUE, REGAL 1993-95 CHEVROLET LUMINA APV 1993-95 OLDSMOBILE EIGHTY EIGHT, NINETY EIGHT, SILHOUETTE 1993-95 PONTIAC BONNEVILLE, TRANS SPORT WITH 3800 ENGINE (VIN L - RPO L27)

CONDITION:

SOME OWNERS MAY COMMENT ABOUT AN ENGINE COOLANT LEAK THAT IS TRACEABLE TO THE VICINITY OF THE THROTTLE BODY ASSEMBLY.

CAUSE:

THE THROTTLE BODY-TO-UPPER INTAKE MANIFOLD SEAL MAY NOT BE SUFFICIENTLY COMPRESSED TO PREVENT COOLANT FROM LEAKING. THIS CONDITION WILL MOST LIKELY BE MORE PREVALENT DURING WINTER WEATHER.

CORRECTION:

REPLACE THE CURRENT THROTTLE BODY SEAL WITH A SERVICE SEAL. THE SERVICE SEAL HAS A LARGER CROSS SECTIONAL AREA (THICKER). A SERVICE KIT CONSISTING OF ONE THROTTLE BODY SEAL, THREE SLEEVE NUTS AND TWO STUDS HAS BEEN DEVELOPED. USE THE NEW SLEEVE NUTS AND STUDS IF THE OLD PARTS BECOME DAMAGED DURING SERVICING.

SERVICE INFORMATION:

TO DIAGNOSE THE CONDITION, THE TECHNICIAN SHOULD COLD START THE VEHICLE UNDER THE SAME OUTDOOR TEMPERATURE CONDITIONS AS THE CUSTOMER DOES (ENGINE COOLANT TEMPERATURE APPROXIMATELY SAME AS OUTSIDE AIR TEMPERATURE). IF THE VEHICLE IS BROUGHT INSIDE THE REPAIR FACILITY FOR A COLD START, THE LEAK MAY NOT BE PRESENT DUE TO WARMER INSIDE TEMPERATURES.

1. PARK THE VEHICLE. 2. WHEN COLD STARTING - SET THE PARKING BRAKE, START THE ENGINE AND RAISE THE HOOD ON THE VEHICLE. 3. LEAVE THE TRANSMISSION IN PARK. 4. FROM UNDER THE HOOD, OPERATE THE THROTTLE LEVER TO INCREASE ENGINE SPEED TO ABOUT 2000 RPM. 5. CHECK FOR COOLANT LEAKS AROUND THE BOTTOM OF THE THROTTLE BODY WHERE IT ATTACHES TO THE UPPER INTAKE MANIFOLD. 8. IF A COOLANT LEAK IS DETECTED IN THIS AREA, REPLACE THE THROTTLE BODY SEAL WITH A SERVICE SEAL.

SERVICE PROCEDURE:

REFER TO SECTION 6E3-C2 IN THE APPROPRIATE SERVICE MANUAL.

PARTS INFORMATION:

THROTTLE BODY-TO-INTAKE SEAL KIT: 17113264

PARTS ARE EXPECTED TO BE AVAILABLE ON APRIL 24, 1995.

WARRANTY INFORMATION:

LABOR OPERATION DESCRIPTION LABOR TIME J5485 R+R THROTTLE BODY SEAL USE PUBLISHED LABOR TIME ADD R+R 1 - 2 SLEEVE NUTS AND STUDS 0.2 HRS

FIGURES: 0 ATTACHMENTS: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

COPYRIGHT 1995 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

Thanks to all who replied. It is possible I just had a throttle body to plenum seal leak, but since I didn't do the test described in the TSB before I tore it down, I won't ever know. I think since I have it down now, I will just replace the plenum and all seals to be on the safe side. I will try to get the updated studs, nuts and seal for the throttle body also. -- Marv

Actually looking at your intake in those pics I think you can go with just some new gaskets. Plenums arent cheap. Do you still have your old plenum to throttle body gasket? If so shove it back in and see if how flush of a fit it is. I've seen them flattened out to nothing on other intakes and that wasnt in your pics so I couldnt tell.