My new oil pressure gauge arrived today and it turns out the problem isnt low oil pressure but high oil pressure.
The Haynes manual says the pressure when warm should be 2.1 bar at idle and 4.9 bar at 4k.
My car has 5.9 bar at idle when cold. I know this would drop when warm but would it drop that much? I didnt want to run the car to warm it up until i
checked unless running it to warm up damaged something.
To give you an idea my oil pressure at idle when cold is 60psi and when hot is 20psi. Thats on 5w40 oil.
So yes it drops significantly.
David
Ah thanks. So, do you think it could be possible that my oil pressure light is on just because it is cold? The last time i ran the engine without the light on was august and therefor the engine would have been much warmer at the start.
IS the switch knackered / connected right?
quote:
Originally posted by stevebubs
IS the switch knackered / connected right?
Likewise, massive difference in pressures
90+ PSI not unusual at cold startup
20 psi ish after shes got up to temp
This is with 5/30 oil, at idle on a Zetec
Fiting my oil cooler has increased the time it takes to drop to sensible pressures...I will get round to buying and fitting a thermostat as it is
probably not doing it any favours
Regards
Rob
Light should not be on if engine is running...ever!!
If is coming on when the car is cold and idling it is telling you pressure is dangerously low..not high and is so low its less than the switch point
(think as std they are set pretty damned low like 5 - 10 psi?) which is bad news as theres not enough oil pressure and damage is probably being
done
I know you can get higher pressure switches so you get a /slightly/ earlier wanring that things have gone badly wrong
I suppose it could be that your switch has gone duff or is wired in wrongly or is one that is set for more pressure than the chosen oil gallery
supplies at idle but...
I personally wouldn't start the car again till its fully investigated with a capillary gauge in the same point as the warning switch was and span
up without plugs in to check that pressure is REALLY being raised first
Are you sure the oil switch is plugged into an oil gallery and not a waterway lol
Is your gauge electric or caplilliary?
Gauge using the sender that came with it?
does it read zero with ignition on and engine not running?
Can you swap the switch and sender for gauge points as one of them is not telling the truth?
Regards
Rob
[Edited as its reads as if you have a gauge which reads OK but a warning light that says low oil pressure??]
[Edited on 8/4/10 by robocog]
It one of
[url=http://www.amazon.co.uk/Draper-43054-Oil-Pressure-Test/dp/B000TODWDO/ref=sr_1_1?ie=UTF8&s=automotive&qid=1270758495&sr=8-1]these[/url
]
It is reading 0 when engine is not running and reading 5.9 bar when first started. The switch is definately plugged into an oilway as i unscrewed it
last week just after starting the engine and oil poured out.
If the gauge reads 5.9 bar [85 ish psi] when cold then assuming it is working right then your oil pressure is fine.
My Zetec reads about 95 when cold.
So either your switch is knackered or there is something blocking oil flow.
Can you plumb the gauge into the gallery the switch is in?
Stu.
quote:
Originally posted by whitestu
Can you plumb the gauge into the gallery the switch is in?