KV6 oil pressure
 

What is the minimum acceptable oil pressure on a 2.5 v6 when hot?

I’ve seen figures of: min 3 bar @ 3k rpm, and min 1 bar at idle, but unsure if these figures are when hot or cold…..I am assuming hot?

In practice, are these figures what can be expected on our engines now they are old?

Those are the figures from RAVE Ash and I too would expect them to apply to an engine at normal operating temperature.

What's your reason for asking? Do you have an oil pressure problem?

Simon

Yes, I done a test yesterday when up to full temp, and was getting 3.5 bar @ 3k rpm (so good) but only 0.8 bar at idle (not so good? Or to be expected on a 120k mile engine?)

Are you using 10W40 oil Ash? When was it last changed?

Simon

Drained the oil out immediately after doing the oil pressure test yesterday and replaced the filter, re-filled with 5w40 on this occasion.

What would you expect the oil pressure to be?

In theory it shouldn't make any difference at running temperature but MG Rover recommends 10W40 for your engine. You could try that the next time you do an oil change.

How are you measuring oil pressure?

Simon

Yes I can’t see the 5w40 causing low oil pressure either.

Oil pressure measured with an oil pressure gauge where the oil pressure switch screws in.

Wow, you mean business don't you! :D ;)
So to return to your earlier question ...
I honestly don't know. I doubt that many people have measured their oil pressure as you have done. :bowdown:

I'd say if it's not illuminating the oil pressure warning lamp and there is no discernible effect on the engine, don't worry about it.

Simon

Yeah the oil pressure light came on when I last used the car - had just come off a 60/70mph dual carriage way and come to a stop at a set of lights and it came on, then went off when I pulled away and would come back on at low rpm/idle.

I’ll see how it goes having changed the old oil and cleaned the oil pressure switch. May repeat the oil pressure test on my ZS 180 to confirm the gauge is accurate

I used to have a Mitsubishi 3000GT for which the manual stated 10W40 oil should be used, however a lot owners used to swear by this 10W50 oil which has a slightly higher viscosity at temperature

https://www.ebay.co.uk/itm/174774140...mis&media=COPY

It might be just enough to boost your oil pressure for a while. It is a bit pricey though! I should state that I have never personally used it in a KV6, so can't confirm any effects, positive or negative.