Buddy's truck need advice please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

AverageJoe · 11-02-2010, 01:08 PM

I'm trying to help my friend who possesses no knowledge of vehicles. (nice way to put it). Im no mechanic But i know something's wrong. His truck is a 91 350 tbi and is losing antifreeze everytime he drives it. I watched under the truck and there is no leaks anywhere (besides a little oil).It loses about a quart on short trips. I pulled the dipstick after the truck had been run and there was little bubbles on it and milky at the bottom. I let the truck cool and checked again and the dipstick had milky swirls all the way up. I assumed maybe a small headgasket problem? Could it be anything else? I know these trucks can build up condensation from sitting, but it only sat for two weeks and it hasnt cleared up in the past few days of driving. Thanks, truck runs perfect too.

ChevyTech · 11-02-2010, 08:07 PM

If he is lucky, it could be an intake gasket leaking into the valley.

If he is unlucky, it could be a cracked block.

AverageJoe · 11-03-2010, 09:38 PM

just replaced the intake gaskets. Turns out the intake was leaking in the back against the firewall, no silicone or anything right there, and along the sides, bad gaskets. oil was everywhere and the valley was full of antifreeze. Fixed the problem, and found out the truck has roller rockers, hardened pushrods, and an aftermarket cam and lifters (i got curious). thanks for the advice.

loudnlifted88 · 11-04-2010, 08:09 AM

hes lucky he didnt lose the crank bearings from the anti-freeze being down there

AverageJoe · 11-04-2010, 12:45 PM

Thats why i was pushing him to quit driving it. Still has 40 lbs of oil pressure on startup, a little under 30 once its warm, but i think it might be bored also.

BigBlocksRule · 11-05-2010, 08:14 AM

Quote:

Originally Posted by loudnlifted88

hes lucky he didnt lose the crank bearings from the anti-freeze being down there

Damn straight! The TBI engines aren't as bad as Vortecs with this problem, but I've seen several with trashed or spun bearings from antifreeze trashing the oil.

piecesparts · 11-05-2010, 08:27 AM

The V-8s in this era of trucks had serious intake gasket problem and they would start leaking at the passenger rear corner. The leak would either be outward to the ground or inward into the crankcase. I would start with a compression check and then go with a plan to check the intake gaskets.

However, you could just plan on new head gaskets and intake all in one shot. It would save cash in the long run for two times in the shop.

AverageJoe · 11-05-2010, 05:02 PM

Quote:

Originally Posted by piecesparts

The V-8s in this era of trucks had serious intake gasket problem and they would start leaking at the passenger rear corner. The leak would either be outward to the ground or inward into the crankcase. I would start with a compression check and then go with a plan to check the intake gaskets.

However, you could just plan on new head gaskets and intake all in one shot. It would save cash in the long run for two times in the shop.

Exactly the problem.

11-02-2010, 01:08 PM	#1
AverageJoe Registered User Join Date: Aug 2010 Location: Rudy AR Posts: 100	Buddy's truck need advice please I'm trying to help my friend who possesses no knowledge of vehicles. (nice way to put it). Im no mechanic But i know something's wrong. His truck is a 91 350 tbi and is losing antifreeze everytime he drives it. I watched under the truck and there is no leaks anywhere (besides a little oil).It loses about a quart on short trips. I pulled the dipstick after the truck had been run and there was little bubbles on it and milky at the bottom. I let the truck cool and checked again and the dipstick had milky swirls all the way up. I assumed maybe a small headgasket problem? Could it be anything else? I know these trucks can build up condensation from sitting, but it only sat for two weeks and it hasnt cleared up in the past few days of driving. Thanks, truck runs perfect too. Last edited by AverageJoe; 11-02-2010 at 01:23 PM.

11-02-2010, 08:07 PM	#2
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,620	Re: Buddy's truck need advice please If he is lucky, it could be an intake gasket leaking into the valley. If he is unlucky, it could be a cracked block. __________________ For those of you that are wondering why you are not getting replies to your thread: Did you give the model, year, engine, fuel system type, and transmission information? If it is modified from what came stock from the factory, let us know that too.

11-03-2010, 09:38 PM	#3
AverageJoe Registered User Join Date: Aug 2010 Location: Rudy AR Posts: 100	Re: Buddy's truck need advice please just replaced the intake gaskets. Turns out the intake was leaking in the back against the firewall, no silicone or anything right there, and along the sides, bad gaskets. oil was everywhere and the valley was full of antifreeze. Fixed the problem, and found out the truck has roller rockers, hardened pushrods, and an aftermarket cam and lifters (i got curious). thanks for the advice. Last edited by AverageJoe; 11-03-2010 at 09:39 PM.

11-04-2010, 08:09 AM	#4
loudnlifted88 Registered User Join Date: Jan 2010 Location: Wales,Maine Posts: 776	Re: Buddy's truck need advice please hes lucky he didnt lose the crank bearings from the anti-freeze being down there __________________ IM ONLY 18 AND LOVIN IT IF MUD AINT FLYIN YOU AINT TRYIN! 1badgmc- Just think. Someone worked hard to make it look that bad. 1988 chevy stepside 305 five speed Build thread http://67-72chevytrucks.com/vboard/s...d.php?t=383945 1994 GMC ext. cab short box 350 auto Build thread http://67-72chevytrucks.com/vboard/s...d.php?t=438873 1996 GMC 2500 ECSB 454 4l80e: build thread http://www.gmt400.com/forum/showthre...gmc-2500-build 1998 GMC K-1500 ECSB 305 auto partd truck 1999 GMC K2500 suburban 350 4x4 Dads project 1981 Corvette 350 auto Also Dads project 1989 Corvette 350 auto ^^ 1998 GMC K1500 ecsb 305 auto Brothers project

11-04-2010, 12:45 PM	#5
AverageJoe Registered User Join Date: Aug 2010 Location: Rudy AR Posts: 100	Re: Buddy's truck need advice please Thats why i was pushing him to quit driving it. Still has 40 lbs of oil pressure on startup, a little under 30 once its warm, but i think it might be bored also.

11-05-2010, 08:27 AM	#7
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Buddy's truck need advice please The V-8s in this era of trucks had serious intake gasket problem and they would start leaking at the passenger rear corner. The leak would either be outward to the ground or inward into the crankcase. I would start with a compression check and then go with a plan to check the intake gaskets. However, you could just plan on new head gaskets and intake all in one shot. It would save cash in the long run for two times in the shop. __________________ Frank



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