Farm Equipment - wd45 oil pressure

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wd45 oil pressure

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=53887
Printed Date: 11 Sep 2025 at 11:00am
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Topic: wd45 oil pressure

Posted By: Allis-chalmers wd45
Subject: wd45 oil pressure
Date Posted: 20 Jul 2012 at 10:11am

Hey guys just another quesgion about my wd when I first got it there was alot of sludge built up under the valve cover and what not the oil was very dark and hadnt been changed in a long time, after changing the oil a few times it was now clean. But my oil pressure was still pretty low, here the thing if I have it at mid to high idle the oil pressure stays up if I idle down or go down or up a hill it drops I don't know what is wrong. I was wondering if I took off the oil pan and cleaned out the screen and all the sludge that is down there will it help me at all? any suggestions please! Thanks justins!

Replies:

Posted By: Allis-chalmers wd45
Date Posted: 20 Jul 2012 at 12:34pm

Please someone help?

Posted By: Allis-chalmers wd45
Date Posted: 20 Jul 2012 at 12:35pm

Please someone help?

Posted By: Gerald J.
Date Posted: 20 Jul 2012 at 12:43pm

Low oil pressure at low engine speeds can come from many causes, and there's no guarantee that only one is contributing.

The sludge could have locked the pressure regulator piston in place so it doesn't close the bypass at low engine speed.

The oil pump pickup screen could be mostly clogged with sludge and grunge.

The rod bearings could have lots of clearance and so need a larger oil flow than the pump can supply.

The crank shaft bearings could be worn...

The cam shaft bearings could be worn....

The pump could be worn.

The oil filter could not have enough restriction to hold up the oil pressure. In the past few years some makers have tried pleated paper filters in place of the original cotton waste filters and those new filters kill oil pressure.

The tube that leads into the oil filter could be missing and that makes pressure not hold up as well.

The oil pressure gauge may be giving misleading readings from rust of gauge parts.

That enough starts?

Gerald J.

Posted By: Allis-chalmers wd45
Date Posted: 20 Jul 2012 at 1:08pm

Thank you very much!

Posted By: B26240
Date Posted: 20 Jul 2012 at 1:15pm

I think Gerald has a complete list of possibilities there.

Posted By: DrAllis
Date Posted: 20 Jul 2012 at 5:03pm

If you truly see a change in oil pressure when going uphill/downhill versus flatland, you better be pulling the pan for a looksee.

Posted By: Allis-chalmers wd45
Date Posted: 20 Jul 2012 at 5:31pm

I really do no joke!

Posted By: Chalmersbob
Date Posted: 20 Jul 2012 at 9:28pm

what do you mean when you say "low oil presure"?

At idle on a WD 5 lbs is good. This is a low presure system, with max being about 18-20 lbs. Do you have the original gauge or one with presure markings? A marked gauge should have a max of 30 lbs to get an accurate reading on the low end. The factory gauge max is around the R-M in normal, at running speed, and as low a N at idle is normal. Bob

Posted By: Allis-chalmers wd45
Date Posted: 20 Jul 2012 at 11:56pm

Then I guess it's fine thanks bob. I'm gonna take off the oil pan tomorrow and clean it anyway