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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22897
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Have a AGU 1.8t running a TD05, ive started getting the stop

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Have a AGU 1.8t running a TD05, ive started getting the stop oil light coming on. The oil pressure is 80 psi on tick over and if revved the warning light comes on. Its running a oil cooler, fresh fuchs 5w 40, new oil pump and pick up, new oem oil pressure sensor and no fault codes other than the 2 I know about maf and N75 both unplugged. What could the problem be?


I'd 1st suggest measuring the actual oil pressure with seperate mechanical gauge - this can be plumbed into the engine via the current pressure switch port - if you use a Tee piece you can keep the pressure switch plumbed in as well and so see if the low pressure light corresponds to a low pressure reading.

As its intermittant and you have no rumbling or rattling noises from the engine its likely to be an electrical fault so 1st check the connection to the pressure switch is bright and clean and check back along the switch wiring for any signs of damage to the insulation

As if the wire is grounded out at any point then this will also turn on the light.

If you do have a low pressure reading ( should be 4 bar (59psi) at 2000rpm) and to turn on the light it will be very low about 5psi then replace the oil pump and ensure that the pump pickup in the sump hasn't come loose or is blocked

Customer: replied 4 years ago.

Hi, thanks for your answer have ordered a mechanical gauge to make sure of the pressure, yes there are no rattling noises to show oil starvation.


Have checked the wire and there is no problem with the insulation and the connections are fine on the plug and its a brand new pressure switch.


The oil pump and pick up have done no more than 500 miles and the pick up is clear.


Thanks any help

Hello Jonathan

one thing to say is the oil pressure does seem high

is this with stone cold oil?

and if you have the original oil pressure switch does this make any difference to the problem if this is fitted
Customer: replied 4 years ago.

Hi, right the warning light has now stopped it was the connection on the plug where it was grounding. With that sorted it has not come on at all but still got the high pressure issue.


I have the oem pressure switch in its normal place and the innovate dual gauge in the other place on the housing with the pressure readings. It hasn't been mapped yet thats next is it going to be ok with this high pressure?

Thanks Jon

Hello Jonathan

Does the oil pressure climb any further than the 80 psi and what does its settle down to once its all hot and at idle?

80 psi is high but if the engine has just been rebuilt and the fact you're running on 5W40 and not the 5W30 which is reccommended for a new engine

so if the oil pressure doesn't climb any further than 80 psi (this should drop to 70 ish with the thinner oil) and the fact it tops out shows the pressure relief valve in the pump is working OK so the pressure will drop slightly as the miles accumulate
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