engine and drivetrain Do I Have An Oil Pump Problem?

[Philbert]

My 74 has an '83 1.8 motor. The oil light stays on for about 5-6 seconds on a cold start, 1 or 2 seconds max or not at all on a hot start. It's been this way for quite a while, not great I'm sure... I parked facing uphill on a steep hill last night for about 2 hours. When i started it, the light stayed on for at least 20 seconds, then it ran fine. Cold start this morning was as usual. The light never comes on after startup. Do I have a problem and if so, any thoughts as to diagnosis and cure? The dipstick shows oil level is full.

[M3M3M3]

when you say "upon start up"....does it stay on if you rev it at tad right after start up.

 

initially i would say you do not have a problem.

[Philbert]

Yes if I gently rev it, the light goes out sooner. I wasn't worried about this until the uphill incident last night. I revved it a bit then and it still took quite a while to build pressure which made me think the pump is maybe beginning to give out... Contemplating a rebuild soon and wondering if I need to add a new pump into the calculation.

[Rocan]

Get an oil pressure gauge and get readings at idle when hot, and at every 1000 rpm. 

 

Make sure your oil is topped off and you are running 20w50; oil pressure may light up at idle once in a while without 20w50. It could be as simple as a warn sender, but until you test it with a proper analog gauge you are simply guessing. 

[Guest_anonymous]

FWIW:

after an oil change and replacing with actual recommended known volume, where does your dipstick read? then compare to what you see now.

[TobyB]

You have an o- ring problem.

 

And a sticky pressure relief.

 

When the relief sticks, it builds too much pressure, and eventually pops the o- ring out a bit.

 

Not a problem- EXCEPT that air can now leak back into the main galley, and that's why it takes

a second (or 6) to build pressure.

 

I seem to have this happen on a regular basis, and some people never have it happen.

I must be lucky.

 

It's a pan- off job to fix...

 

t

[M3M3M3]

You have an o- ring problem.

 

And a sticky pressure relief.

 

When the relief sticks, it builds too much pressure, and eventually pops the o- ring out a bit.

 

Not a problem- EXCEPT that air can now leak back into the main galley, and that's why it takes

a second (or 6) to build pressure.

 

I seem to have this happen on a regular basis, and some people never have it happen.

I must be lucky.

 

It's a pan- off job to fix...

 

t

that is interesting toby.  counter intuitive.  too much pressure leads to not enough pressure!

[Philbert]

Thanks all. Toby B that's about what I expected to hear. So new o ring and relief valve cleaning I guess. Doesn't sound too hard to fix except for the pan-off part. There's some kind of natural law that governs the timing these things- had the subframe off last winter for bushings etc and of course this didn't show up before then...

Phil

[Philbert]

Thanks all. Toby B that's about what I expected to hear. So new o ring and relief valve cleaning I guess. Doesn't sound too hard to fix except for the pan-off part. There's some kind of natural law that governs the timing these things- had the subframe off last winter for bushings etc and of course this didn't show up before then...

Phil

[TobyB]

Yeah, I have never honed the bore on the relief valve, but others say it works.  When a pump was $150, I changed them.

Next time for me, I'll try the hone, now that a pump's $500!  (I think you can get the hones at a motorcycle shop)

 

when you take it apart, before you drop the oil pump, look at where the tube drops down from the relief

passageway- you should see this little hernia of o- ring squeezed out.  It isn't much- and I can never believe

that that LITTLE bubble can do it, but on 2 of 2 I've fixed, there it is.  On Jenns, I haven't taken it apart yet,

but I guess I'll have to do it pretty soon...

 

Others- including Byron- have never seen this and look at me quizzically.  

 

There are different types of tubes- I have often wondered if they are dimensionally different or something...

 

t

[Preyupy]

I have not had that O ring blow but I can sure believe they can. If you have to use a thick shim to get the oil pump chain tensioned correctly you have pulled the tube slightly out of the recess in the oil pump, that might be something to look at. I also make sure to test fit the oil pump with the O ring before I tighten the hold down bolt for the pressure relief tube on the block to make sure it is centered correctly.

[Philbert]

Great advice, thanks again! It'll be a while til I get to it but I'll report back on what I find. Will be fixing tranny rear seals and various oil leaks at the same time. If I'm going to crawl under there I might as well take care of whatever I can...