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Need help with no oil pressure problem

2174 Views 8 Replies 5 Participants Last post by  BenC
I was crusing along the freeway when I noticed the oil pressure guage
drop to nuthin. I have a '66 Mustang with a stock 289.
I pulled off and shut it down as quick as was safe and I'm about to go
drop the pan to take a look see. Anyone want to wager what it may be.
I'm hoping something as simple as a seized oil pump or broken shaft but someone has suggested a rod bearing.

Any ideas?
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Check the easy stuff first; make sure the wire from the oil pressure sending unit is still connected and didn't work it's way loose or something, and then check to make sure the guage is working. Would hate to tear into the bottom end if it was something similar in the wiring. Bad sensor or burnt wire, etc.
Also pull the distributor and check the hex in the bottom and the shaft that drives the pump to make sure it isn't stripped. I had that happen on a big block before. I had an oil pressure drop on a 302 once and it was the relief valve on the pump blown out.
I pulled the distributor and had a look. The hex on the bottom
of the ditributor seems fine; but looking in; the oil pump shaft seems
to be WAY lower than the distributor can reach.
I got a primer down there and tried to prime the pump but I'm not sure it
even engaged properly on the shaft.

I'm thinking I'll drop the pan and take a look. Never done it before - shop manual
makes it look easy; though my buddy reckons I may need to raise the engine.

Any real world experiences of dropping the oil pan on a '66 with a 289 ??
Will dropping the crossmember be okay?

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If both front frame rails are securely on jacks you can remove the cross member and get in there. I am not sure but you may have to remove the steering linkage too. It's just 2 nuts and one tap with a hammer on each. :)
Hello.:)You have to remove the cross member,as has already been stated.You also have to take the two bolts out that hold the idler arm and then pull steering linkage down as far as you can without damaging anything.That will give you enough room to get the oil pan off.Before you put it back on clean the gasket surface of the pan and the bottom of the block,use a new gasket along with new front and rear seals.Don't overtighten the bolts and you should be fine.I think that I'd make sure that it wasn't the sending unit or sending unit extension clogged up before I went through all of that,though.Good luck.:)
Here's the problem (see attached).
Seized up tighter than a nun's ..............


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This piece of very brittle PLASTIC (attached) was in the bottom of the pan.
A similar sized piece got through the screen in the pickup and
seized the pump. Any ideas on what it is or where it came from,
or why....lot of questions :)

Also, here's one of the main bearings....I can't tell if the wear is
normal for a 40 year old engine or caused by running it
(for a VERY short time) with a seized pump


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I don't think thats plastic. It probably feels like plastic, but it looks like a piece of very old, brittle rubber, like a valve stem seal. Wouldn't be the frist time that has happened. Did you say the motor was 40 yrs old? Its never been rebuilt? Its hard to say, but main bearings are replacable, the real question is if the crank or rod journals are scored. If not, consider yourself very lucky and do a rebuild. Hope this helps. Your Friend, BenC
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