low oil pressure [Archive] - Chevelle Tech

: low oil pressure


Satellite
Jun 10th, 99, 8:28 AM
I've got a '71 Malibu with about 120K original miles on it. The oil pressure on the gauge is barely coming to the normal operating range. Will replacing the oil pump help to bring it back?

jholp
Jun 10th, 99, 9:27 AM
Satellite,

Assuming you have a small block Chevrolet you could put the Corvette/Chevrolet Z-28 oil pump in it which would jump it up there but it is a band-aid fix.

With that many miles on it you may need a rebuild. How much oil does it use between oil changes?

You could retorque the mains when you put in a higher pressure pump in but once again I don't think you are getting to the heart of the problem.

You could pull a main cap or two and have a good engine builder visually look at bearing wear. I have seen people "sneek" a thicker new bearing half in the main cap but oh boy this is not the way to do things.

Is the engine leaking at the rear oil seal?

Does the engine "rattle" at bit when you first crank it?

Have you done a compression test on it to give you some further understanding of the engines state of health?

John

Gene Chas
Jun 10th, 99, 10:33 AM
Satellite, John's probably right. Your engine is just getting loose, hopefully, not too loose in a critical area like a bearing clearance. Have you tried running heavier oil? Again, just a band aid, but you may get some more life out of that motor ( like Castrol 20-50w).

By the way, throwing a HV oil pump on a loose motor will just increase it's consumption of oil.
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[This message has been edited by Gene Chas (edited 06-10-99).]

283v8
Jun 10th, 99, 11:56 AM
Depending on the care the engine has had, it may not be badly worn. Check the gauge and all connections from engine to gauge to ground. Check the sending unit.
Check the pressure with an oil pressure gauge on the engine??
Personally I'd like to know before a rebuild.

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"Let me live in a house by the side of the road and be a friend to man, - with a garage and a smallblock Chevy"

Satellite
Jun 10th, 99, 12:26 PM
Thanks for all of the info. I neglected to provide some needed information.

To answer some of John's questions:
It does not rattle upon startup.
It uses about one half quart between oil changes (3500 - 4000 mile internvals)
No leaks from the stock 350 engine.
Run 10W-40 in the mild Seattle climate.

I was thinking that the low pressure maybe beginning to starve bearings or other areas from oil and that a new pump would address this. I've owned the car four years and its always ran smooth. Bodywork and real nice paint are coming first. Rebuild will follow in a couple of years.

Since I have this new oem pump shall I install it? Is is anything more than inside the oil pan and a few bolts?