1997 Chevy 3500, 350 V8 sporadic oil pressure

[raymond338]

I have a 1997 chevy 3500 with the gas 350 V8. 47,500 miles, but it was a crew truck and I suspect it may have spent a lot of time idling and that it never left the government park it lived on (therefore may not have hardly ever warmed up).

 

Here's the symptoms:

When cranking up, the oil pressure reaches 40-45, but in a very "jerky manor". Occasionally, when warm, the oil pressure takes a second to kick in and the lifters tap for a second.

 

The oil pressure stays in a decent range, even when warm. Does this sound like an oil pump issue? That's my first and only guess.

 

How hard is changing the oil pump on this truck? That is, do I have to lift the motor up, or is there clearance?

 

thanks in advance for any and all input.

 

raymond

[95Sierra2500]

If it's a 4x4 then I'm pretty sure you'll basically have to pull the engine to change the oil pump as the front diff is in the way. If it's a 2wd truck then you might be able to drop the pan and get it out of your way with the engine in place, but I'm not sure and have never done it this way. I usually just rebuild the engine while I'm at it. However, my '95 with the 350 does this as well, and Im pretty sure it's from idling alot over its life. After a while it smooths out, however.

[90GMCZ71]

Before you replace the oil pump, I would hook up a mechanical gauge and make sure that this is not an oil sending unit or gauge issue.

 

If it is 4x4 and the oil pump needs to be replaced, you can do it with the engine in the truck; however, you will need to lift the engine 4 or 5 inches with a cherry picker. The fan schroud and dist also need to be removed. The Y-pipe needs to be removed from the exhaust manifolds. The motor mount pins are removed and then the engine can be lifted.

 

//90GMCZ71