Author Topic: do oil pumps fail suddenly? (Read 3322 times)

Vanagoner · « **on:** July 01, 2008, 08:34:54 am »

I just got my 81 n/a mechanical back on the road for a test drive yesterday after finishing the head gasket job. It had been sitting for two years before that.
anyhow, after 15 uneventful miles, the oil pressure gauge showed a sudden drop from 22 down to about 7 and she started a-knockin a little. I had it pulled over and shut down within 20 seconds. The oil level was still full on the dipstick.
Is it possible for pumps to suddenly fail, or am I looking at something else?
Thanks

riddleyo · « **Reply #1 on:** July 01, 2008, 09:11:15 am »

If you want to do a quick check, drain the oil and unbolt the oil pan. Check for gunk in the screen of the oil pump and tighten the 2 bolts that hold the oil pump to the block.

My low oil pressure problem was because one of the bolts had vibrated loose. That and there was a bundle of hair stuck to the oil screen.

After that is done, bolt the pan back up and remove the vacuum pump by removing the one bolt. Take an electric drill with a hex socket on it (I think it is 13mm) and spin the oil pump shaft. See how much oil pressure you are getting. If it is still low, you will have to look at the oil pump or bearings next.

zukgod1 · « **Reply #2 on:** July 01, 2008, 10:31:08 am »

As rilddleyo has mentioned check the screen for gunk, other than that it's possible the intermediate shaft bearing went to crap.

You didn't mention though if upon restart the pressure was good again.
Was it? If it was it's prob a blocked screen as already mentioned.

Vanagoner · « **Reply #3 on:** July 01, 2008, 11:07:41 am »

Dan, I haven't tried re-starting it yet- she sits in a parking lot. I didn't want to risk damage 'till I figure out what is going on.
So perhaps gunk got stirred up after a few miles and plugged the screen, and may drop out enough for a re-start? I'll give that a try and let you know- thanks all.

rabbid79 · « **Reply #4 on:** July 01, 2008, 03:07:21 pm »

I'd give riddleyo's bolt tightening idea a try. It's very important that those bolts are tight. Especially since there's no gasket or o-ring between the oil pump and block that might otherwise help compensate for less than optimal bolt tightening.

the caveman · « **Reply #5 on:** July 02, 2008, 10:49:12 am »

This is not gospel and i'm certainly not saying they never fail, but i've never seen one fail after 25 years working on vw's EXCEPT one in which the releif valve failed and blew the filter and made the motor throw a rod.
If you have low oil pressure i would suspect bearings etc first.

riddleyo · « **Reply #6 on:** July 02, 2008, 12:03:23 pm »

Quote from: "the caveman"

If you have low oil pressure i would suspect bearings etc first.

You are probably right, but it is always good practice to check the easy fixes first then move to suspecting the harder ones.

rallydiesel · « **Reply #7 on:** July 02, 2008, 12:38:16 pm »

More likely intermediate shaft bearings.

myke_w · « **Reply #8 on:** July 02, 2008, 01:23:29 pm »

I've also seen belts so loose they fail to turn the int shaft pulley