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GreesonDW

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What's up everybody, I'm a newbie on this forum. I am delighted to be part of this online community. Hope everybody is ok and having fun while learning here.
 
1997 gmc 1500 xc 5.7ltr oilpreasure issues?

Hello everyone,

Here is my delima, I have a 1997 GMC 1500 XC 4x4 w a 5.7 ltr ( 140,000 mi),
I have been having problems with the oil preasure, when I replaced my lifters
I had very little oil coming through my push rods, even after cleaning the same. Ran Marvel mystery oil trought a couple times and changed oil & filters too.

I would occasionally have the preasure gauge drop from 30 to 20 and bounce to 0, which would set off the check guages light, but when I throttle up preasure would come back and light would go out.

I just changed my sending unit ( it was all sludged up ), but it did not resolve the issue, and this past weekend replaced oil pump with a high volume pump. When I started it up I hd 60 lbs but as the truck warms it slowly drops below 20 and occaisionaly bounces to 0, and sets off the check guages light, but when I throttle up preasure comes back and light would go out.

Can a worn crankshaft seal cause this? because I have noticed some oil around the timming cover, and was wondering if any of the mystery oil I put in to clean out any sludge could have weakend or destroyed the seal?

Other than that the truck runs like new.


Thanks in adance

Kerry in Quincy ma.
 
Generally speaking a loss of oil pressure in an engine is a result of
a) wear, meaning that the your camshaft and crank bearing gaps are larger than spec.
b) spun bearing in camshaft, this is noticable by lack of oil at top end of engine.

An engine oil pump is a postive displacement pump meaning that it will put out the same volume of oil per revolution. Pressure in the oil system is a function of the restriction of the passage of the oil to flow thought the engine.

When you replaced the oil pump with a high volume pump, did you check or replace the pressure relief?
 
I replaced the sending unit behind the distributor, where is the relief valve ?
 
Hello everyone,

...and this past weekend replaced oil pump with a high volume pump. When I started it up I hd 60 lbs but as the truck warms it slowly drops below 20 and occaisionaly bounces to 0, and sets off the check guages light, but when I throttle up preasure comes back and light would go out.

In your post you said you replaced the oil pump with a high volume pump. The pressure relief should be part of the oil pump.

What brand oil pump did you put in?
 


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