Chim low oil pressure

[max500]

Just noticed that my oil pressure gets very low when hot- at zero at times. Oil level is OK. No improvement to pressure when hard revs. Does anyone have any ideas?? Thanks

[ssc1]

so what pressure is it when starting from cold , and does the pressure go up when you rev it when cold , and does it only go to zero when its hot, we all know what the pressures should be so i'll not go into that, what oil are you using, and also it could just be the sender unit failing when hot as with zero pressure on the gauge i would be expecting the oil light to come on followed by alot of rattling sounds if you are going fast. get it checked .

[marco]

Mmme

My Griff 500 has just started doing this.

Pressure reads absolutely fine hot or cold except when it has been idling for 3 or 4 minutes and is hot. Then it drops right down near zero but with no oil warning light illuminated. Add 200rpm and it perks back up to its usual 15psi idle position. Engine sounds and runs perfectly.

I hope somone can pacify me with an "its definately the sender" type message! I'm going to get it checked out ASAP anyway.

Question - when very hot, idling at 1250rpm instead of 1000 makes the pressure sit at the normal level and its fine the rest of the time, so is there a reason I can't drive it in the short term with a slightly increased idle speed?


Thanks


Marco


Edited to add Mobil 1 always used, idle pressure @ cold = 30psi, running pressure hot or cold = 40psi, idle pressure hot (for the first couple of minutes) = 15psi

>> Edited by marco on Wednesday 9th July 08:52

[shpub]

The idling is controlled by the ECU and can't be changed. SOunds like a sender but as you say get it checked ASAP.

Steve
www.tvrbooks.co.uk

[marco]

Thanks as always Steve.
I'll follow that advice.


Marco

[GreenV8S]

If you have the normal thin 0/40 type of Mobil 1, you'll find it gets so thin when the engine is hot that you get no oil pressure at tickover. The thicker 4T/Motorsport type is better. Also, if the oil level is low the oil will run hotter which makes it even thinner. So if the oil pressure starts to dip, check the level.

[chimburt]

don't take this as any guarantee, but my car did much the same, until the sender finally gave up, then the oil pressure reading depended on whether i was going round a left-hander or a right!
incidentally i have had 2 of these go in 24k miles.

[ajg]

When I first got my Chimaera the oil pressure would drop to BELOW zero (on the gauge) when the temperature was around 90'C. Replaced the oil pressure sender and now never drops lower than 15psi when hot, 45 when cold.
New sender was about £50.
Worth getting it checked out though, due to damage to the engine if the pressure is really zero.
Does the oil pressure warning light ever come on?

Andy G

[shpub]

Yes! about 4-5 seconds before the engine is history!

[max500]

Thanks seens likely to be sender but will check. Thanks

[marco]

Hi

I called Richard Smith @ Peninsula and he agreed that it sounded like a sender problem. A few numbers read out, £45 debited and it will be with my next day.

He tells me they're not difficult to fit - any experience?


Marco

[ajg]

marco said:

Hi I called Richard Smith @ Peninsula and he agreed that it sounded like a sender problem. A few numbers read out, £45 debited and it will be with my next day. He tells me they're not difficult to fit - any experience? Marco

Located at the bottom of the engine, access is good with the car on a ramp, just need the correct open ended spanner and a few rags for the oil that drips out between taking the old one off and fitting the new one (not that much oil though).
Obviously don't cross thread it or get dirt in.


Andy G

[marco]

Thanks for that.

Just to close this one out, my new sender arrived on Friday as promised and I fitted it Saturday morning. Note that there is a thread converter between the sender and the engine that you have to swap over or you end up calling Richard to see why he sent the wrong one and feeling stoopid.

Result is an increase in the pressure reading across the board. Just over 45psi when driving and an absolute lowest reading of just under 30psi when idling.

Also (and I know this HAS to be my mind playing tricks) the car seems to perform so much better now! Perhaps driving with both eyes on the road rather than one on the oil pressure helps .


Marco