Low oil pressure

[johnsastra16v]

Just had a new oil pump fitted, and now the car runs beautifully

I have calibra gauges (so not the most accurate, but do give an indication).

On cold start up it sits at 5bar

But after about 10mins of driving when the car reaches temperature, at idle the oil light on the dash flashes and the gauge reads a tiny bit above zero.

a quick dab of the revs and it goes out. the car drives fine.

Ive topped up with oil, so oil level is now at max on the dipstick

As its a new oil pump, could it be the grade of oil causing this. its currently full of 5w 30 vauxhall oil.

Or could it be the sender?

How about the relief valve? But the oil pump has literally only been on for 2weeks max.

 

[Jayc20xe]

What sender are u using?

 

[johnsastra16v]

i got the sender about 3years ago from autovaux. its the standard sender with the extra connector for the gauges

 

[Jayc20xe]

Hmmm if it was after market I would say that's the issue! Clean the pressure valve and then see.

Wiring is ok to sender?

Was it a new OE pump?

I'm sure if it was about 0 she would start rattling very quickly!

 

[johnsastra16v]

well there no rattling

it was a copy pump from autovaux (i was told new OE pumps dont exist anymore)

i havent checked the wiring just yet, but id rule that out as the oil pressure reading is fine when cold.

 

[Jayc20xe]

Valve is first then!

I had a similar problem but it was the sender, but to double check myself I bought a manual pressure gauge from eBay was about €15 hooked it where the sender goes and it gave the right readings so I knew then it was the sender.

 

[johnsastra16v]

what do you mean "valve is first then"??

 

[johnsastra16v]

oh you mean the relief valve. yeah i'll get it checked

 

[Rad666]

I take it you uavnt seen any threads about autovaux oil pumps?

 

[wayne1]

I've got the same problem as you John. When cold it reads 5 after 10mins driving it it drops down just over zero

 

[Rad666]

Iirc when hot it will read about 2.5 bar then rise when you rev

 

[johnsastra16v]

I think it should idle at 1.5bar

 

[Andy_Mk3]

If never use anything but a GM pump, I was very lucky to find one cheap!

 

[johnsastra16v]

It seems to happen quicker after I rev the car quite a bit.

HAppened again tonight. Let it idle with the oil light on but no noises from the engine and idle fine.

hoping its just a dodgy sender then

 

[johnsastra16v]

as well as a low pressure reading at idle, there is a high pressure reading at normal driving.

there are also no funny noises from the engine

could this rule out any damage to the engine, and merely a sensor/relief valve issue?

 

[johnsastra16v]

could the oil type play an impact?

as its got 5w 30 in it, not the usual 10w 40

 

[Andy_Mk3]

Ought to have 10w40 in it. Although I've got 5w40 fully synthetic in my mk4 and it runs much quieter!

Is the gauge and the light running of the same sender?

 

[johnsastra16v]

yes gauge and light are running on same sender. its the same sender from a cavalier/calibra with gauges