29 replies to this topic

[Big_Adam]

thats what i'd go with. big job to replace from what i've read too.

also if the car dies when you open the oil cap then its weak not rich. there is a pipe on the carb connected to the crank case. the oil filler cap is a filter so it lets air in. the gases go round the engine then into the car thro a breather pipe. if the car stalls with the cap off then too much air is getting to the carb. with a high air mix then the car stalls.

[Dan]

as the light goes off at higher revs is it safe to say that the pump is probably up the duff ?

Either that or the oil pressure releif valve is stuck or the engine is generally worn. It could be that the pressure sender switch is broken but if that happened it would more than likely just stay on all the time. Given the previous owner's attitude to maintenance I would guess at worn bearings but that still means engine out the same as a new oil pump does. Try cleaning and reseating the pressure valve just in case it is that but it's not likely.

Edited by Dan, 23 May 2006 - 06:51 PM.

[dan_g]

can i replace the pump without taking the engine out ?? (i cant find my haynes atm so im unsure of the process)

[pikey7]

you have to take the clutch off, so not really...

check the relief valve first. much easier.....

[dan_g]

ok, thanks alot ..... how will i go about doing this ?

[Big_Adam]

taking the engine out.....errmm.....unblot eveything and watch it fall.

[dan_g]

lol......... i meant checking the relief valve

[pikey7]

its a big "bolt" at the front of the engine, just by where the sensor and the oil-tube is on the LH (as you look at it) side. take it out, check the spring, in fact replace the spring and the cup thats in there, and give it a go.

[dan_g]

thanks alot for your help ..... i will give it a go 2 moz when it is lighter

[Big_Adam]

lol......... i meant checking the relief valve

d'oh sorry.

[1984mini25]

If the relief valve is sticking then you could replace it with the ball and spring one from minispares.com

Oil release valve kit. Part no. AEA536KIT
As fitted to the original cooper S and also helps the engine run smoother.
Also if the current pressure relief valve spring is shorter than 73mm then its only fit for the bin.

While you’re at it replace the oil switch, just to be on the safe side.
Part No. GPS133

[syholl]

Am i right in saying though, that the oil pressure relief valve doesn't affect the oil pressure whilst the engine is running at idling speed, only when you rev the engine does the oil pressure relief valve do anything.... Just what i remember reading somewhere...

[1984mini25]

But if the pressure relief valve is stuck open then it will allow the oil to flow back in to the sump bypassing the engine, giving low oil pressure at idle.

The reason why they are fitted is when the oil pressure is too high, it opens and allows some of the oil to flow back in to the sump reducing the oil pressure to a more reasonable amount.

too much oil pressure can be just as bad as too little oil pressure.

[pikey7]

and also why the light goes out at higher revs when its "supposed" to be open.

[1984mini25]

At higher rpm the oil pump is working harder meaning it is producing higher oil pressure; some of witch is not needed so the relief valve opens to reduce it.

The pressure relief valve is NOT open all the time.