14 replies to this topic

[Biteable]

Hi all

I have put in a Smiths oil pressure gauge and to my horror have no pressure reading
I change to the gauge as my oil pressure switch is not working

Anyhow things I have checked:-

I removed the OIL GAUGE PIPE from the gauge and only dribs and drabs of oil come out on crancking
I have also removed the OIL FILTER TRANSFER PIPE from the block, and again only dribs and drabs of oil come out

I have primed the pump again and again
I have removed and cleaned and refitted the oil pressure relief valve

Do I need to replace the oil pump

Thank you for any input
Mick

[Pauly]

For cheapness I would fit a new oil pressure switch and see if the light goes out on the dash. Could be a faulty gauge?

[yellowmonster]

Even the most worn pump pumps....only not as good as it should.
If you're able to prime the pump, the gears are probably okay.
Although of 'English buildquality', oilpumps on Minis aren't unreliable.

Remove the oilpressureswitch from the engine and put the adapter for the gauge in, connect the (transparent?) oilline and gauge and start the engine.
If your switch is still all right, you can first put a splitter in the engine (like the T-piece of a brakeline..) so both the gauge and the switch can be connected.
If both the dashlight from the switch stay on and the gaugereading gives nada, there's something wrong with the pump.
(STOP THE ENGINE)
Else, and this would be my main suspect, the 'new' gauge is faulty.

Edited by yellowmonster, 07 August 2011 - 10:31 AM.

[Biteable]

First thank you both for trying to help. Much appreciated

I have tested the gauge by putting an air line to the back of it ( on very low pressure ) and then winding the pressure up and down. The gauge moves up and down with the pressure.

Another question. If the oil pressure relief valve is not sitting right home could this give me the symptoms I am getting

I have cleaned it but could it not be sitting right home

Thank you
Mick

[yellowmonster]

Yes it could; if it stays open there's no way the pump can build up pressure....
All the oil will 'leave' the system thru this bypass back into the sump without doing its job.
Tackle that relief valve first!

[Biteable]

Ok Matey thank you so much

[dklawson]

You've done a good job troubleshooting the gauge. Do check out the relief valve as you mentioned, then do a little searching here for methods to re-prime the oil pump. Though not terribly common... it does happen. I seem to remember people removing the banjo bolt , filling the oil pipe with oil, and turning the engine backwards by hand to suck oil through the filter and back to the pump. Anyway, it sounds like you are on the right track and know what you are looking for.

[Biteable]

Ok what I have done is to remove the relief valve and give it a good clean up. Still have the problem. I have measured the spring and it is a little short of the spec. I am talking mm's so not a great deal of difference.

What I am going to do is to buy a new relieve valve set up. Will go for the spring and ball. And then go from there

I have primed the pump using the above method and used about 250ml of oil. How much oil should it take to prime
What I did was to put oil into the block, where the Banjo is fitted, had it in 4th gear, pushed the car backwards and watched the oil be taken into the block.

Thanks again to everyone trying to help
Mick

[Biteable]

I have today fitted a new relief valve, the spring and ball type
Still no pressure
Could it be a blocked oil pick up in the gearbox ?

What I am thinking is to loosen off the blanking plate, on the back of the gearbox, by taking out one bolt and loosening the other. Don't want the pipe to drop into the gearbox. Then put an airline in the opening and blowing, gently raising the psi, to see if I can hear any sort of gargling. A long shot I know

If there is a blockage and it clears, I could then give it an oil change to try to get rid of the crap
What do think or am I talking out of the top of my head. Tell me straight, I can take it

[dklawson]

This is a hindsight question. Did you separate the engine and transmission recently? If so, did you remember to re-fit the o-ring seal between the two?

[Biteable]

Yes the engine was rebuilt.
I put the engine and gearbox back together and definately put the little rubber O ring in.
I am 100% sure I did that.

It looks as though I am going to have to split the engine and gearbox doesn't it
Not to bad a job as I have a removable front end. Just a bit of a kick in the danglies

Just to add ---

Could the O ring somehow not be sealing properly and drawing in air. I am getting some, not all the time, oil coming from the oil gauge pipe, and it is full of air

Edited by Biteable, 10 August 2011 - 04:10 PM.

[Biteable]

Ok I have sorted it.

What I did was split the engine from the gearbox and found that the gasket was far too thick. Which was preventing the engine from squeezing down onto the oil pickup sealing ring.

The gasket was a Payen one and was about 2mm thick

Now all ok after fitting a new gasket and oil pickup seal from MiniSpares

Thanks again to all
A very happy Mini owner again

Edited by Biteable, 21 August 2011 - 12:29 PM.

[yellowmonster]

Sorry to read you had to go thru all that trouble of splitting the engine again.
Glad to see it's all sorted now!
So the Payen gasket is crap? (Where did I read that earlier..?)

[dklawson]

Great News ! I'm glad you sorted it. Those gaskets do sound like they were awful thick.

[bmcecosse]

Sounds like you had a gasket for an inlne 1275 engine - as per Spridget - they are same shape - just thicker since the sump is made from 'tin'.