tedharris

New Member
127k miles
1996 model
After reading the search results I changed the pressure sensor - Britpart - made no difference, electrical connection was oily, but as the light is working can I assume the terminal is ok - easy to change otherwise

There was a smell of bad oil as I took the old sensor out.
I do oil changes very regularly, once a year and car only does about 1k a year.
Just changed the oil again. Nice and clean on dip stick.
10w40 I think. or was it 5w40? Semi synthetic.

I did add a bottle of Slick50 for the first time ever this time.

Anyway, this is totally new to me. Owned the vehicle over 15 years.

It is only on startup that the light stays on (longest was for about 6 seconds) then goes out and stays out.
If starting engine after it has just been turned off, no light.

Interestingly, if the car has been in the sun all day, the light stays on longer than if it has been a cooler day upon start up.

Lifting the bonnet, I do sense things seem and smell a bit warmer than they used to, even after a short run, but that could be my imagination and that we have just had Summer here in the UK.

Any ideas would be really welcome. Thanks
 
127k miles
1996 model
After reading the search results I changed the pressure sensor - Britpart - made no difference, electrical connection was oily, but as the light is working can I assume the terminal is ok - easy to change otherwise

There was a smell of bad oil as I took the old sensor out.
I do oil changes very regularly, once a year and car only does about 1k a year.
Just changed the oil again. Nice and clean on dip stick.
10w40 I think. or was it 5w40? Semi synthetic.

I did add a bottle of Slick50 for the first time ever this time.

Anyway, this is totally new to me. Owned the vehicle over 15 years.

It is only on startup that the light stays on (longest was for about 6 seconds) then goes out and stays out.
If starting engine after it has just been turned off, no light.

Interestingly, if the car has been in the sun all day, the light stays on longer than if it has been a cooler day upon start up.

Lifting the bonnet, I do sense things seem and smell a bit warmer than they used to, even after a short run, but that could be my imagination and that we have just had Summer here in the UK.

Any ideas would be really welcome. Thanks

I may be wrong, (don't rush to answer), but shouldn't the oil be thicker than 5w40 ? In case it doesn't handle that sort of pressure in the sensor ... IYKWIM ...

I'd reckon on 20W50 for a long in the tooth lump ...
 
15w40 for the 300TDi.

Best way to be sure it to jam an Oil pressure tester in where the sensor goes and get the pressure at idle when cold/hot and at 2000rpm..

If you don't do that then guessing is the next best thing..

The pickup pipe O ring can go rock hard and bleed pressure/ suck air for the first few seconds upon startup causing the pressure to remain low for the first few seconds.

Or if it a high mileage lump, the 5w might be the cause. .

Or wear in the crank bearings.
 
I may be wrong, (don't rush to answer), but shouldn't the oil be thicker than 5w40 ? In case it doesn't handle that sort of pressure in the sensor ... IYKWIM ...

I'd reckon on 20W50 for a long in the tooth lump ...

Check the viscous fan, thermostat and get the EGT checked and make sure the oil is getting to the top end properly ...
 
right thanks.
The sensor was stiff to get out AND no rubber or ntrile o ring came out, just a copper washer. The Britpart one just had a washer and no o ring, so thinking your air leak idea could be on the nose.
Will check the other things mentioned too.
Thank you
just looking for a pressure gauge and found this video in case of use to other readers.
 
It could well be the oil pressure relief valve sticking open slightly, but as others have said a mechanical oil pressure gauge will tell you exactly what’s going on,
I would drain the oil and put some flushing oil ( highly detergent) through and run up to temperature, it will help to clear the oil galleries/ oil pump Gause and pressure relief valve,
 
This gives you the expected oil pressure you should be seeing, and you should be using 15/40w
Semi synthetic oil
F76C80BA-245D-4803-A3C7-B57B93B949D3.png
 

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