Engine Oil Light ON - help and advice

BMCC · Post by **BMCC** » Tue Jan 07, 2014 6:30 pm

Cant see an idle speed like that bringing the light on, the idle on my 5g has been lower than that and its never flickered. Got an oil pressure gauge and even with a low idle it sits about 1 bar.

'92 Si VTEC · Post by **jjmartin349571** » Tue Jan 07, 2014 6:38 pm

I can't say I've had it on a Honda, but on my VW if the idle gets to 500ish RPM then the oil light very dimly flickers - this was why it sprung to mind. It is a different kettle of fish engine wise though so fair point on that front

Post by **Thebusofwoe** » Tue Jan 07, 2014 6:55 pm

Low idle could cause low oil pressure but it would have to be real low, like barely idling.

I ordered those bits as a precautionary measure for mine today, £15 bargin

h10ndr · Post by **h10ndr** » Tue Jan 07, 2014 9:42 pm

Oil light switch is on at 7psi...

BMCC · Post by **BMCC** » Wed Jan 08, 2014 7:56 am

h10ndr wrote:Oil light switch is on at 7psi...

Idle oil pressure should be a min of 10psi which is closer to the switch pressure than I expected.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Wed Jan 08, 2014 8:46 am

If we made a crude assumption that pressure is proportional to rpm then, idle dropping from 950 to 500 rpm could drop pressure by more than 3psi then (i.e. to less than 7)

BMCC · Post by **BMCC** » Wed Jan 08, 2014 11:17 am

wurlycorner wrote:If we made a crude assumption that pressure is proportional to rpm then, idle dropping from 950 to 500 rpm could drop pressure by more than 3psi then (i.e. to less than 7)

Its possible but my Lude's normal idle oil pressure (~750 RPM) is about 1.1 - 1.2 BAR so around about 17.5 PSI. I bunged on alot of the electrics in the car to get the idle to drop (~500RPM) and it was about 0.9 BAR = 13 PSI. On mine I'd have to be about stalling to get the oil light to come on.

Post by **Merlin** » Wed Jan 08, 2014 11:33 am

Yeah the oil pressure sensor is a load of guff and only tells you that something is broken, rather than about to brake.

The service manual says that if oil pressure is below 10psi at idle the oil pump should be the first thing to inspect/replace (page 8-10 of the 5th gen service manual).

Fingers crossed that when you remove the oil it isn't full of bits.

h10ndr · Post by **h10ndr** » Wed Jan 08, 2014 1:14 pm

If you've ever nearly stalled your car, but just caught it, you will have probably seen the oil light flash on before....I have...

Salazar · Post by **Salazar** » Wed Jan 08, 2014 10:12 pm

Thanks Wurly, I'll check out those links to the idle valves and check they're functioning ok before starting work on the oil pressure relief valve. Sure, I'll take some pics of the work on Sat mate. The coolant has been in there for 4.5 yrs so I can't see why it would suddenly need bleeding? It's a 5yr coolant so will need changing in the 6months or so though.

Thanks for all the replies and input guys, much appreciated. I'm thinking I could just put my foot very gently on the accelerator to bring the revs up to 750-850rpm and see if the oil pressure light goes out? That should show if the low rpm is causing the light to come on.

I bought an oil pressure gauge this week and will be testing the oil pressure on Sat before and after the pressure relief valve swap and oil change. I think it's probably unlikely that the low oil pressure is caused by the 500rpm idle speed, but I'll be able to monitor the process from a cold start on the gauge. Rich at PAW said the oil pressure at idle should be around 20psi, and yeah it states in the workshop manual the pressure should be 'at least' 10psi.

I think the oil will be fine and not show any metal shavings, I have a Skunk 2 magnetic sump plug so it'll clearly be evident if there's anything like that going on. The engine sounds absolutely sweet as always.

Lude Generation

Engine Oil Light ON - help and advice

Re: Engine Oil Light ON - help and advice