Oil pressure

[David Mantle]

God !@#$ and !@#$ it -- my oil pressure has now decided not to extinguish the light after about 8 seconds from cold. I reckon the oil pump pickup is faulty but could be one of the crank journals damaged or worn. Guess I am off the road for a while but I hope not for too long as I want to tour Europe next summer. -- Geeesshhh I am pissed off. At least I have an old CX as back up so things could be worse.

 

[joedrum]

:shock: hmmmm...get some diesil or something dave and setup up a motor flush with pump and all to ....and let it run for dys cleaning the inside of that motor ...making sure it covers all parts of inside over time with different feeds and returns ..and hands on guilding ..til youthink its spotless in there ...the moving fluid principal cleans everything if given time ...thats what id do ...then try it again ...ive never heard you complain about noise in lower end ...and im doubting that

 

[dan filipi]

I've had this happen a few times and found the oil pickup screen was clogged.

 

[roncar]

I've had this happen a few times and found the oil pickup screen was clogged.

+1

Only once did I see an oil pump replacement required to get the pressure up. The old one 'looked' fine but when swapped, the pressure came up. Could have been something else that was cleared during the replacement, but once it was working......

 

[joedrum]

sheesh ive never seen one that bad

 

[David Mantle]

I have already cleaned the pick up screen and ran her on diesel for a couple of days ( only short journeys ). These were the first things I did about a month ago but the problem seemed to have only got worse. Funny thing is the motor is still quiet with NO knocking or any strange noises of any sort.
I hope to start tearing the motor down in February when I have a week off work. And yes - I have a new oil pressure switch . Fitting an oil gauge in situ only confirmed that there is zero oil pressure for the first few seconds of starting then the pressure rises showing 60psi after about 7-8 seconds. It is during this period that I believe long term damage to the crankshaft will occur and I don`t fancy a crankshaft failure at speed or miles from home.

 

[Steve83]

Several years ago, a friend had the same problem with his '81 1100. He checked the oil pickup screen - clean. He removed the engine, replaced the oil pump and checked all the bearing clearances, which were all good. He put it all back together, and still had no oil pressure for 5-8 seconds on a cold start. A warm start was better, but still had a slight delay.

It turned out to be a small crack in the front cover, near the bottom of the oil filter mount. It was allowing the oil to slowly drain from the filter housing back into the sump, so during a cold start, the filter and housing had to fill with oil before the pressure would rise.

With your engine cold, remove the filter housing and note how much oil drains out. There should be quite a bit. If not, the oil is returning to the sump - somehow.

I hope this helps, and you don't have to tear down your engine! If you're eventually getting 60 PSI, the oil pump is working, and with no knocking, your bearings - for now - are OK.

 

[joedrum]

thats great steve and something to look at

 

[dan filipi]

Pressure once it does come up is too good to be a pump problem in my opinion.
To me it sounds like it could be loosing its prime after sitting or like mentioned oil has to fill a space before pressurizing the oil gallery.
I would look for a crack anywhere in the suction side of the pump channel, even in the screen pickup housing itself. Anywhere it could possibly suck air.

Curious, what is the hot oil pressure at idle
If it's 10 lbs or higher your bearings are in ok shape and the pump is doing what its suppose to do.

What about the oil filter and housing itself?
Is the spring and washer in place where it should be?

 

[dan filipi]

Something else I thought of, does the oil filter center bolt act as a check valve? If so and it's leaking.....
Also maybe it's lazy and not holding pressure like it should at first?
I'm not certain how that thing works and all its functions, just throwing out ideas to hopefully avoid splitting the engine open when otherwise in good running condition.

 

[AApple]

Something else I thought of, does the oil filter center bolt act as a check valve

I think it does. The only way for oil to completely drain out of the filter housing is if there is air getting into it at rest. If the valve is stuck even partially open, that would do it. Or if one of the seals on the filter is leaking/torn. Or a crack somewhere, as Steve mentioned.
I've run mine with no spring or washer on the filter before, and it always pumped oil pressure up quickly.
Adding an extra quart of oil would help eliminate any leaks on the suction side of the pump, I think....that should be enough to cover all of the suction side parts, including the pump itself. :headscratch:

 

[dan filipi]

Maybe try fill oil over full as a test.

 

[joedrum]

yes good point joel...adding more oil at this point is wise

 

[DaveO430]

Something else I thought of, does the oil filter center bolt act as a check valve? If so and it's leaking.....
Also maybe it's lazy and not holding pressure like it should at first?
I'm not certain how that thing works and all its functions, just throwing out ideas to hopefully avoid splitting the engine open when otherwise in good running condition.

NO, it is a bypass valve in case the filter gets plugged, it is not a check valve at all.
My 83 was a little loose at ?20,000 miles when I bought it. Took a few seconds to build pressure and you could hear some noise until the light went out. I put a spin on adapter and a filter with a check valve to solve the problem.

 

[mcgovern61]

Did it sound like this:

 

[DaveO430]

Did it sound like this:

Yes.

 

[mcgovern61]

Did it sound like this:

Yes.

I have a thread you might be interested in:

viewtopic.php?p=56923#p56923