Oil pressure?

[KENCO]

What should the normal oil pressure be with engine warmed up and at idle?

1990 SE

Mine seems to be low, not in the red but low. When the rpms go up its fine.

I dont know if I should use thicker oil or the gauge is off, or maybe something else?

[dazmans3]

Hi Ken

I have just put an HC engine in mine. rebuilt it with new main barings & oil pump, to name a few things.

Pulling 90 on cold start & I noticed today settled to about 45 once warmed up. thats with 20w/50 mineral oil, which I m using to run in engine, them will be going over to Castrol RS 10w40.

Bare mind I am using the non electric LC type oil pressure gauge.

In the final hrs of my LC engine, it was pulling about 60 on cold start,settle at 30ish but would drop below 20 when off excellerating. I also have a blown head gasket, to add to this.

The book states minimum pressure at 3500 rpm =35 & at 6500rpm 45

Daz

[siocox]

Hi Ken

Lotus also give an idle figure of 5 psi in my book, I was concerned because my oil light will flicker at idle when hot so I contacted some lotus independents, it is quite common and ok provided at higher rpm the pressure is ok.

Regards

Simon

[Techspy]

Hi Ken

Lotus also give an idle figure of 5 psi in my book, I was concerned because my oil light will flicker at idle when hot so I contacted some lotus independents, it is quite common and ok provided at higher rpm the pressure is ok.

Regards

Simon

Yeah this is a known issue. I have the same symptoms. I checked it with a different mechanical gauge and confirmed all is ok. I replaced the stock vdo gauge with a new one and replaced the sender with a new one..still the same..I just disconnected the second wire going to the sender that is for the light only.

Edited August 10, 2007 by Techspy

[KENCO]

OK, Thanks!

Makes me feel better.

I am in hot Florida, when I change my oil, should I put in 20W 50?

I dont know what is in there now.

Edited August 10, 2007 by KENCO

[Paul93Lotus]

I always had good pressure on my last 93- it would be at 2 bar at idle, and just past the middle of the gauge while cruising on the freeway. Never had the oil light flicker. The car had 38K miles. I was using Castrol Syntec in that car. I believe 15-50 or 20-50?

On my 95 S4s. the oil reading is decidedly lower. Like around 1.5 bar at idle. 3 bar while cruising. But that is with the Caerbont style gauges...so who knows if the sender is reading right until I hook up a mechanical gauge to verify. This engine has 19K miles! I believe what is in there right now is 20-50 valvoline Racing

So go figure. Normal oil pressure on these engines seems to be all over the place.

[jpspeedy]

I always had good pressure on my last 93- it would be at 2 bar at idle, and just past the middle of the gauge while cruising on the freeway. Never had the oil light flicker. The car had 38K miles. I was using Castrol Syntec in that car. I believe 15-50 or 20-50?

On my 95 S4s. the oil reading is decidedly lower. Like around 1.5 bar at idle. 3 bar while cruising. But that is with the Caerbont style gauges...so who knows if the sender is reading right until I hook up a mechanical gauge to verify. This engine has 19K miles! I believe what is in there right now is 20-50 valvoline Racing

So go figure. Normal oil pressure on these engines seems to be all over the place.

I am using 20w50 in my 89SE and when it hot at a idle it's read just above the red zone and running down the road straight up middle. but that is when it 90+ outside.

[Artie]

I see about 1bar at idle when hot (and over 95F outside), when cruising it only goes up to about 2.3 bar or so.

Art

[Tony K]

A healthy engine, fully warmed up with oil fully warmed up will make 15-25 psi at idle under normal everyday driving conditions. This number drops as the engine wears. If a 9XX engine is making 5psi at idle at normal operating temperatures and everyday conditions, the bearings and thrust washers are probably very worn.

However, when you drive a healthy 9XX hard, you will see the oil heat up and the pressure drop. Drive on the expressway casually for 15 minutes and note your oil pressure. Then do 2-4 laps around a track and see what your pressure is -- it will be decidedly lower, and that's where you might touch 5 psi at idle.

[KENCO]

Will thicker oil or an additive help?

Edited August 17, 2007 by KENCO

[siocox]

Hi there

I have connected an oil pressure external gauge to the oil temp sender port, at idle with a cold engine 50 psi on external gauge, car indicates 1 bar. When hot 15 psi on external gauge, car gauge well ito red and oil light flickering.

You have to confirm what your actual oil pressure is before doing anything else.

Regards

Simon