Low oil pressure when hot....

[cat007]

Hey all

I'm running Valvoline VR1. I can't remember what I have in there - I have a feeling it was the 0w-60 stuff because I had planned to give it a bit of track use and it'd be exposed to a fair amount of heat - but have topped it up with about half a litre of 10w-40 a few weeks ago.

I've noticed my oil pressure seems very low. I am looking at the stock gauge - so it might just be inaccurate.

When hot at sitting at motorway cruising speeds it sits around 2-2.2kg/cm2 - which is around 28-31psi.

This seems pretty low to me.

Unfortunately I haven't driven the car in a while and cant remember what it used sit at.

Is this too low? What normally causes low oil pressure, other than worn out oil pump? Worn big/main bearings will do this or?

Cheers!

Hunt

[CAMB01]

What revs is it sitting at, at that pressure? What pressure does it go up to as the revs increase?

[cat007]

What revs is it sitting at, at that pressure? What pressure does it go up to as the revs increase?

Engine is doing about 3,000rpm.

Pressure goes up to about 2.5kg/cm2 when hot. When cold it'll get to about 3-3.2kg/cm2...

[MAC_HATER]

I was on the 10-40 VR1 stuff and would get the idiot light flickering or lighting up at idle, must have used it for a year and always after a hot run it would do this

ive since moved to Castrol Edge 10W60 and i can thrash it as hard as i can, and get it hot as hell, and no more idiot light now at idle, so different brand, and difference viscosity, seems to have helped? I cant say what numbers its doing, as i dont have an actual gauge though

[CAMB01]

Try changing to a higher viscosity oil and see what happens.
Seems too low to me, whats the pressure at 6000rpm?

It could be a number of things its hard to diagnose over the internet, or it could just be normal or could be a worn oil pump or the oil is getting too thin when hot but the cold pressure seems too low as well. So many possibilities.
General rule of thumb is 10psi oil pressure every 1000rpm. Generally most cars should see over 60-70psi cold and generally no less than 50psi hot at highish revs.

[Mr Ree]

I think it sounds like it would be within spec, so check the TSRM to conirm.

[limbo]

Stock oil gauge wont read any kind of accuracy and will probably be heavily damped so you wont see any fluctuations.

Most electric aftermarket gauges are pretty terrible too, I have never had one that reads right despite running its own ground and positive to the battery.

On my 7mgte the oil pressure is 4.3psi at hot idle from factory.... lets not get int that discussion. However the only gauge that seems to work is a mechanical gauge. I currently have a $15 one from repco and its the only time I have had any real feed back on what is going on.

If you are concerned put a cheap mechanical on and run that for a while until you know whats happening.

[cat007]

Stock oil gauge wont read any kind of accuracy and will probably be heavily damped so you wont see any fluctuations.

Most electric aftermarket gauges are pretty terrible too, I have never had one that reads right despite running its own ground and positive to the battery.

On my 7mgte the oil pressure is 4.3psi at hot idle from factory.... lets not get int that discussion. However the only gauge that seems to work is a mechanical gauge. I currently have a $15 one from repco and its the only time I have had any real feed back on what is going on.

If you are concerned put a cheap mechanical on and run that for a while until you know whats happening.

Thanks for the replies. Yeah I'll track down a mechanical gauge and chuck it in. I won't however have it in the cockpit as I've had first hand experience as a passenger when a mates civic's mechanical gauge decided to part company with the hard line in the back of it and spray oil all through-out his interior haha.

[Mr Ree]

What does the TSRM say about your OP?

[cat007]

What does the TSRM say about your OP?

I've yet to track one down for the 1G haha

I did find this on the interwebs however....

"I have the Japanese manual and while I cant read it, it does suggests the following at operating temp (80-90degC):

0.4kg/cm^2 at I assume idle (5.7psi)
4.2kg/cm^2 at 5000rpm (59.7psi)"

So for some reason my oil pressure isn't what it should be at high rpm - which isn't ideal. But I am going off the stock gauge - so I'll beg/borrow/steal a mechanical one and see what's really going on...

[Mr Ree]

Is it possible that your factory sender is tired too?

I know the factory gauges are only an indication, so trying a proven gauge is a good idea.

What oil filter are you running? How old is it? Im guessing the original oil pump?

[cat007]

Is it possible that your factory sender is tired too?

I know the factory gauges are only an indication, so trying a proven gauge is a good idea.

What oil filter are you running? How old is it? Im guessing the original oil pump?

Yeah original pump - I don't think I did anything to it when I rebuilt the engine so it's probably got a good +150K's on it. I replaced the releif valve spring with a new one from Toyota - but that's it.

Oil filter, hmmmm I can't remember. Something off the shelf from repco/supercheap. It's probably got about 2,000km's on it.

[Mr Ree]

Have you done anything else recently that could influence the OP?

E.G Installing an external oil cooler etc?

[cat007]

Nah

Have had the oil cooler in place since the rebuild. Nothing else added or removed that'd affect oil pressure.

I'm starting to lean towards the factory gauge being crap.

I'll find a mechanical one for testing and go from there.