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Oil pressure warning - hot weather?

cvega

Well-known member
Joined
25 Feb 2013
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437
Oil pressure warning came on today after about 40 minutes in stop start traffic in my car, when I put the car in neutral and revs dropped.. It goes away with higher revs. I changed oil in the car last June. I think it was 0w40. Should I panic ?
Car driven maybe once a week.
 
May need a little more info

Did the oil pressure needle go to zero completely (sender has failed or could be dirty terminal contacts ) or just showing very low hot oil pressure at idle?

Also, many miles has the motor covered?
 
Motor has 142k miles, well maintained as far as I can tell.
Pressure did not drop to 0, but dipped under 1 on the gauge when idle ( intermittent, light goes away with raising revs)
 
Confirm oil pressure with an external test to totally rule out the sender. Also pull the oil pressure relief valve and check the spring is intact at correct length and the plunger isn't stuck (they can score with age)

If the above is fine I would change the oil anyway as you are nearing 1year service life (infrequent short trip use may have diluted it with some fuel). Move onto something thicker like millers or another 50 weight spec and see if this helps your hot pressure.

Is the water temp fine?
 
Water temp sits bang in the middle of the gauge.

Where is the oil pressure relief valve located ?
 
Hmm, doesn't sound great but don't panic yet.
The oil pressure in the old air cooled cars could get very low at hit idle, so much so that the oil light would flicker on sometimes.

I'd drop your oil and check for debris in filter. If ok put 10w 50 in for better hot protection and keep it on max.

A little trick to raise revs and oil pressure slightly is put the air on on. It raise revs a touch and the engine idles much nicer. Well that's the case on 3.4s anyway.

Other option is get a proper oil pressure gauge on it to see the true reading.
Maybe a job for your mechanic.


ETA - Harv beat me to it. He speaketh sense. :yes:
 
you need to get the actual oil pressure checked by a garage or you buying and rigging up the kit to test it . .. not the gauge as it may be a sender fault ( electrical fault ) .

If that confirms low oil pressure then the pictrure below is the first thing to check as if its not that you have a problem .

Basically its oil sender unit , oil gauge , pressure regulator .. then its .. lets not go there for now .

EDIT ..

From experience the oil sender units normally give a false high reading on the gauge as they wear out .
 

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Worth checking the oil level also. If it's low you can get low oil pressure too
 
Hope its nothing serious and just a faults sender. but drop that oil as IMO running a 142k mile car on 0w40 is :eek: :eek: get 10w50 in it ideally millers nano plus but if you dont want millers get some -any brand 10w50 in it :thumb: :thumb:
 
Thanks guys, I'm looking into trailering it to the nearest indy (BTW any recommendations in East Anglia - please!)

Double whammy as it failed MOT today for a stupid reason ("Can't secure back seats in upright position - metal shaft broken !) and I Have 10 days for a retest).
When it rains, it pours...
 
Hot idle is always the most severe case for low minimum oil pressure due to the low engine speed. What was your water temperature? Also what was your idle speed?
Both these things will have an impact on your oil pressure.

First thing is do is change the oil as it's as near as 1 year old now and I'd go 10W-50. Just for some added protection.
 
skinny_monkey said:
Hot idle is always the most severe case for low minimum oil pressure due to the low engine speed. What was your water temperature? Also what was your idle speed?
Both these things will have an impact on your oil pressure.

First thing is do is change the oil as it's as near as 1 year old now and I'd go 10W-50. Just for some added protection.

Water was straight up, needle perfectly vertical. It was 27C outside and i was in stop-start traffic for about 30-40 mins prior to the warning coming on.
 
Had a look in the garage , oil is fully synth 5w40, is that still too thin ?[/list]
 
Not really. 5/40 is approved for these engines but as they get up to higher miles lots of people switch to a 50 for better protection when hot.

In theory your oil light shouldn't come on even with a 5/40 so there may be a problem.
However your car is high miles, it was hot weather and you were stuck in traffic for a while.
As said the first thing to do is get a proper pressure reading. The dash gauge is a rough guide at best. Then go from there.

Good luck.
 
Thanks.
Getting a trailer arranged and having it investigated.

Of course it had to happen when weather turns to summer :D :D :D

DAMN OLD CARS!
 

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