Thread: Oil Light coming on ,help needed.

The presumption is you have a 3.9 v8. As such, (In the absence of more info ) there are three areas to look at
1. Rockers: If you've looked under the covers, when hot, there shouldn't be too much oil coming out the sides of the rocker arms. If it is, then a new rocker shaft is in order
2. Main bearings: If you have time, whip off the sump and have a look at one of the mains and one of the conrod bearings.
3. Oil pump: Last port of call for oil pressure loss. May have to find a pressure gauge to diagnose it properly.

Solutions:

Roughest: Do an oil change and use a heavier oil ( ie for 'older' vehicles) or some of that no-smoke dodgy stuff.

Rough: Bung in a set of main and conrod bearings (You can do that in situ), or a 2nd set of v8 rocker arms

Sort-of-rough: take of the front cover of the engine and install a new oil pump. ( If you have a 3.5 it unbolts.)

I know others will have other opinions, but basically you should figure out where the oil pressure loss is happening quick.


EDIT: Now that we know it's a 300 tdi, the Mr BB and Mr LRing are correct - true idle hot pressure first. I'll change my guess to loose rocker shaft rather than worn - you can still do bearings in situ, but the oil pump is a bit of a major job.

i had the same problem with my 300tdi (only did it when warm) and i changed the oil, bought a vdo oil pressure guage to replace the clock in the dash to see what was happening and all it was was a faulty oil pressure switch!

your first check is to put a manual oil pressure gauge in and check the true oil pressure
cheers
blaze

As others say new sender to start with,cheap and easy.Yes a mechanical gauge will help too.
Ensure the wire hasnt either worked loose or has rubbed thru.It could be intermitently getting a false earth thru a rubbed thru cable or be touching an earth if its come adrift.Both will cause the light to illuminate.
GOODLUCK
Andrew

Originally Posted by LandyAndy

As others say new sender to start with,cheap and easy.Yes a mechanical gauge will help too.
Ensure the wire hasnt either worked loose or has rubbed thru.It could be intermitently getting a false earth thru a rubbed thru cable or be touching an earth if its come adrift.Both will cause the light to illuminate.
GOODLUCK
Andrew

I have my fingers crossed that its the Sender, I can't afford a big repair job a week before the school holidays. Thanks for your input.

Do you own a multi meter?.If you do set it to Ohm's and check from the terminal to the switch body,it should be closed circuit,with the motor running it should be open.It is common for them to leak oil and cause the light to come on.If you like a quick check is to remove the rocker cover and start the engine,oil will squirt up if the pressure is alright. Pat

Thanks Pat I will give that a try, I did notice a small amount of oil on top of the diff when I had a look last night.

Thanks to everyone for there advise, just got the good news that it is just a failed oil pressure sender. Unfortuneatly I have to wait until tomorrow for the new sender.

Jeff