GM Vehicle Leaking Intake Manifolds-Anyone? - READ ONLY

29 messages, Last post on Aug 08, 2002 at 8:53 AM

You are in the Maintenance & Repair - Archived Discussions Forum. Your Host is mr_shiftright

This discussion is ARCHIVED. To reactivate the discussion, post a request in the Lost? Ask the M&R Host for directions! discussion.

What is this discussion about? Chevrolet, Buick, Oldsmobile, Engine

Outline

Messages Page 2 of 4: 1; 2; 3; 4; Prev; Next; Last

#4 of 29 2 Corsicas by adc100 May 10, 2002 (3:49 am)
92 3.1- 125 K when leak occurred 94 3.1- 76K when leak occurred I have heard the DexCool theory but I don't believe its the whole answer. Dealer told me in 2001 that it was still occurring even with DexCool. I assume it is a problem with Aluminum heads/cast iron block. Great engines otherwise but fatally flawed. Does anyone know if the 3.4 engine is prone to this? My understanding is -yes.
#5 of 29 leaking intake manifold 97 tahoe by jack937 May 11, 2002 (6:00 pm)
97 Tahoe 4dr 4wd 350V8 75000 miles. Replaced leaking intake manifold.
#6 of 29 DIY Repair or Not by rs_petty May 13, 2002 (9:38 am)
If anyone with this problem has done the repair I'd like to hear any tips. My 99 Lumina just diagnosed with this problem. How hard can it be?
#7 of 29 95 Silverado Pick Up by chuckm6 May 13, 2002 (10:22 am)
My wife drives a '95 Silverado, which she bought new with the 5 liter V8. She changes oil and filter at 3,500 miles. The truck now has 71,000 easy miles on it. One day she said the oil pressure gauge was doing funny things and then stabilized. I checked her oil and found it to be down almost two quarts in about 2,500 miles. There are no external leaks, and no smoking, even at start up. The tail pipe has no oil residue in it. After the last oil change I added a quart at 1,700 miles. I just changed the spark plugs and the PVC valve. There was a little oil on the air cleaner cover. The Dexcool (late 95 trucks) is past due to be changed, which I will do very soon.---Might this problem have something to do with the leaky intake manifold you described?
#8 of 29 98 silverado by wtd May 14, 2002 (2:17 pm)
I had the intake manifold gaskets replaced on my 98 ext-cab Z-71 with the 5.7L V-8 at 24,000 miles. Luckily the truck was still under warrenty. Mine was leaking at the front and rear of the engine. This is a widely know problem with the Vortec V-8 engines. The mechanic that worked on mine said that the intake was torqued down too tight from the factory, eventually causing the gaskets to crack and leak. This might be the reason the intakes on the above mentioned cars are also leaking. Wayne
#9 of 29 by jc1973 May 14, 2002 (10:11 pm)
well i have a 1994 sunbird with the 3.1 engine which was very poorly maintained for the first 80000 miles have a 150000 on it now and still havnt had a problem how can you actually tell when the gasket is going
#10 of 29 3.1 Repair by rs_petty May 17, 2002 (6:54 am)
The gasket is plastic with the seals imbedded to just seal the runners. Mine had cracked causing the leak. The symptom is coolant loss. My wrench said it cracked from the heating/cooling cycle and he'll probably see more - probably exacerbated with 2 different metals (aluminum and cast iron). Confirmed the same on the Vortec engine and the lack of chevy putting enough bolts on the manifold - said there were only about 2-3. The repair is very difficult (8 hour shop time). Intake disassembled, fuel rails/injectors removed, rocker arms and pushrods removed, engine tilted forward, and then all put back together. The stinker is that GM part was all that was available - no better aftermarket design. Stupid GM engineers - my last chevy.
#11 of 29 by alcan May 17, 2002 (10:44 am)
Here's the book time for V6 Sunbird intake manifold replacement: 1984-2000 Models Sunbird Four... 3.9 hrs V6.... 5.4 hrs Includes: R&I plenum, runners, fuel rail, and injectors
#12 of 29 '99 Venture by davy1 May 20, 2002 (12:56 pm)
Intake manifold leak at 59k. Kicker is that the dealer says manifold gasket is back-ordered with no anticipated delivery date. Mentioned he has 2 others on the lot also needing the same repair. Same problem killed my 84 S-10 2.8Litre 4WD when it had 104k.
#13 of 29 '96 GMC Sierra by mcpdjohn May 20, 2002 (1:59 pm)
I just recently had that problem with my '96 Sierra 5.7 liter Vortec. I had 79K on the truck, but the coolant change interval is "100K miles or 5 years, whichever occurs first". I was two years beyond the time limit, and I believe my Dexcool went acidic as a result, costing me a new gasket. I did the job with a friend. It was a big job (IMHO). We had to pull the distributor too. I wouldn't recommend this job to just anyone. You need to be pretty competent under the hood to get this one done. I bought a Fel-Pro gasket set from Auto Zone and it worked fine. My lesson learned is, change coolant in accordance with the maintenance schedule. I don't blame this one on GMC. I blame myself.