1986 GMC Jimmy Engine Overheats after Rebuils

SEANSJIMMY

MEMBER
1986 GMC JIMMY
V8
4WD
AUTOMATIC
70,000 MILES

Hello --

I had a new / rebuilt Chevy 350 engine put in my son's 1986 GMC Jimmy full size. First off -- there is no disptick. We were driving to Denver and noticed that the oil pressure gauge was at zero and the temp was up to like 180 degrees. Went to Jiffy Lube and they said there were just 3 quarts of oil in the car. They changed the oil with 5 quarts at this point the engine only has like 200 miles on it. Now the oil pressure gauge goes up under heavy acceleration but otherwise still sits at zero. Worse, the engine rocketed from 180 degrees to 260 degrees and overheated. Wont stay much below 200 degrees now when at highway speeds.

HELP! Have all the new parts in this engine been fried?

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Hi SeansJimmy, Welcome to 2carpros and TY for the donation

Do you have any type of engine knocking noises?

Check the oil pressure with a mechanical gauge if normal replace the oil pressure sending unit, abnormal could mean oil pump and engine bearings

Overheating could be that the engine is not fully broken in or a thermostat problem

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Saturday, July 10th, 2010 AT 7:11 PM

SEANSJIMMY

MEMBER
2 POSTS

Thanks for writing back. No engine noise at all -- nothing bad that is.

So there may be two seperate problems -- something oil related and something thermostat / new engine related.

Is there any chance that the engine builder forgot to put in an oil pressure regulator? I will have to get to the store for the mechanical gauge.

Assuming engine overheated because it was not getting oil, what happens to all those new engine parts -- metal spalling? Is that what it is? Is that fixable or do we need to do a full rebuild?

He said he put in an oil pump that measured out at 67 psi -- which he said would work better for a new engine putting out more heat / HP.

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Saturday, July 10th, 2010 AT 9:55 PM

RASMATAZ