19 replies to this topic

[Austin mini 30]

Hello everyone. 

 

I have a Mini 30, 1989 but I have a 1275 engine out of a 94 mini in it. 

 

Recently the oil pressure light has been flickering so I fitted an electrical gauge to see exactly what was going on. 

 

On startup I am getting between 50-60psi, and then after 10 - 15 minutes of driving once the engine warms up the gauge just keeps getting lower and lower until its floating between 5 and 15 psi.

 

The engine was fitted with a new oil pump with new oil and filter in September last year when it was out and I have covered around 4000 easy miles since. 

 

I fitted a new relief valve last night but the problem still persists. 

 

Was thinking of doing an oil and filter change tonight and seeing if anything happens because it is due one. If not I guess it is engine out time... but Instead of diving into that, could an oil pump really fail after only 4000 miles? Has anyone experienced this before? 

 

Was thinking their could be a blockage somewhere.... or bearings but i'm not sure. 

 

The car drives absolutely fine with no bad sounds but I wont be going any further until this is resolved 

 

Any help is much appreciated as always 

 

Thanks

[nicklouse]

pull the pressure relief valve and check for it sticking and/or damages sealing surfaces. as it may just not be closing correctly.

 

as standard it lets oil by at about 60-75psi

 

it may just be sticking open.

[DeadSquare]

If the oil pump has failed, you wouldn't  have 50/60 psi on starting.

 

High oil pressure is nice to have, like a silver beer mug, but it is how much beer in it that counts.

 

One of the things that the oil does is to cool the bearings, so it is a good thing to have plenty of oil flowing out of the bearings.

 

If you remove the oil pressure switch when the engine is hot and align a clear plastic bottle, by spinning the engine over you could satisfy yourself that the pump is or isn't working well.

[unburntfuelinthemorning]

Why was a new oil pump fitted last September?  Was other work carried out?

[Austin mini 30]

Hi guys, 

 

Thanks for your replies! Will try your suggestions after work today and let you know how things go. 

 

Last September i swapped from a 998 to a 1275 and fitted a new clutch, crank seal, new oil pump, water pump etc and a general service to the 1275. Only done this because the engine was out of the car and It made sense to me to do it there and then before it was put in. 

 

Cheers 

 

Will get back to you all this evening after I have tried your suggestions 

[mini13]

so its low at idle when hot, whats it like when you rev it?

[Austin mini 30]

Its low all the time when hot yeah - Idle and driving. If i go along and lift my foot off the throttle the pressure goes up. If i rev it, it goes up a fraction. Hardly driven it since this has started - only down the road for tests.

 

Went on a drive last night for example from cold. Engine started up and was getting 50-60psi, driving at low speeds round through the town i was still getting good pressure depending on the revs. Once the engine heated up to temp outside town, sitting at 50mph it went from good pressure slowly down and down till eventually far too low and had to stop.  

 

Just to add the engine burns no oil and oil leaks are minimal (hard to believe!) and I have hardly had to top it up since the last oil change. 

 

I'll spend a night in the garage tonight and see what I can do and will get back to you. Fingers crossed its simple but fully prepared for an engine out job if necessary. Just want to rule out everything else first. 

 

Cheers  

[unburntfuelinthemorning]

What engine oil did you use?

[Austin mini 30]

I use Halfords 20w50, are there any better alternatives you would recommend? 

[Cooperman]

The first thing to check is the actual pooil pressure. You mentioned fitting an electrical gauge, but a more accurate reading is always obtained with a mechanical gauge, as used on the early Minis.

 

Once you have established that the oil pressure drops right off when hot, check the pressure relief valve for sticking, although when this valve sticks the pressure will come up again when the engine is revved. I had this with a 1275 and although with the relief valve stuck open and reading about 5 psi at tickover, it came right up to around 50 psi at 4000 rpm.

 

Take no chances with engine damage and if the pressure is low, pull the engine, strip it and examine for the reason, then rectify it.

[Austin mini 30]

Hi Cooperman, 

 

No problem, I think I have access to a mechanical gauge so will fit that and see. Will do, thanks for your help will let you know what happens once I try that.

 

If it is still not right after that the engine will be coming out to investigate

 

Thanks 

[unburntfuelinthemorning]

I use Halfords 20w50, are there any better alternatives you would recommend? 

Not the best in the world but shouldn't give you those problems.  Just making sure you weren't using something like 0w20.

[cal844]

Yes there is better oil out there but the Halfords and Comma classic oil does the job, I've done 5000 miles between changes with no damage but I wouldn't recommend it.

Hope this helps

[Dusky]

Tbf, sounds just Like a worn engine. Especially with both the gauge and the light telling the same story.

[Spider]

Sounds like worn bearings to me.