Oil Pump Replacement

Nenw

Nenw

Well-Known Member
Getting ahead of myself on this but it's on my mind with about a thousand other things.

My oil pressure has been dipping when at low idle and also when things are running warm. The little warning light will come on.
At some point I will be digging in to replace the water pump and redo all my seals, so I may just replace the oil pump while the front of the engine is off. I only want to go in one time.

So questions.

1. How often do these fail?
2. How big of a pain is it to pull
3. If I am replacing the entire unit, can I put the later model on an earlier van? Anything else I would need to swap out if I do this?
 
If just doing the pump itself, all of the 4D56's from 1990-on use the rotor type pump. It's a big job, and I don't think it is at all common... a rotor type pump is pretty foolproof.

Bearing wear can also cause a decrease in oil pressure... it might not be the pump...
 
Uhg, don't tell me that it could be a bearing :eek:.
I have a pre-facelift van so I'm on the driven gear not the rotor.

I will look into what the job requires. I have enough big jobs...timing and water pump aren't critical yet, so perhaps I address other potential issues first and see if things change.
 
The oil pump is a big piece, it includes the alternator bracket, front section of oil pan flange, balance shaft seals and drives. It's not a quick or easy thing to replace. As @sk66 says it's a robust item, but it could be damaged if there was lots of metal in the oil pan like from a failed rocker.

I would have the oil analysed (look for recommendations on bobistheoilguy.com). That'll tell you if there's bearing material in the oil.

You could also try changing the oil pressure switch, it's possible yours is getting tired.

What oil are you using? 15W40 is correct, but you could try a 15W50 which won't thin out so much when hot.
 
noted. I will look into the oil pressure switch and when i am back to driving the van, not just planning on driving it, i will get an oil analysis done.

I had one done in the past and nothing worth noting though they mention there was high iron in it, which could be caused by idling a lot, which was probably the case, since i was spending lots of time on trail. I never got around to doing a follow up.

Since then I did have my balance belt break and timing jumped a tooth. I replaced my rocker shaft out of an abundance of caution. Probably safe to say after that is when i started running into this issue.

Coincidence???? It was a decent repair that did coincide with very hot weather, and very hot weather long distance driving.


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Nenw said:
I replaced my rocker shaft out of an abundance of caution. Probably safe to say after that is when i started running into this issue.
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Other than incorrect installation, IDT the rocker shaft is likely causing the issue... and if it was installed incorrectly you would have much bigger issues.

Definitely test the pressure switch... seems like the easy place to start.

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sk66 said:
Other than incorrect installation, IDT the rocker shaft is likely causing the issue... and if it was installed incorrectly you would have much bigger issues.
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Right, and it likely wouldn't have made a trip up and down the coast along with some hard wheeling if it wanted to be catastrophic.

I looked at some other threads about the oil pressure switch. Was thinking that I already replaced it which is why I went to the pump theory, but my Amayama order history is not pulling up the part#, so I guess I will check the switch and perhaps just get a new one anyway since it's so cheap.
 
DustAngel said:
Check the wiring to the pressure switch also
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As I mentioned above, I feel like this is a case of deja vu and that all of this has been done at one point. I'm mixing up realities.
What I did vs what I read that other people did vs what I did with other people. o_O
 
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