Jump to content

TD5 oil light stays on at idle


Recommended Posts

I'd say get a gauge on it. A proper [mechanical] oil-pressure gauge on the dash - in place of the original clock - was one of the first things I did when I bought my 90.

For reference when completely warmed-up my 2001 TD5 running on 15W-40 fully-synthetic oil reads 45PSI when the engine's on the rev-limiter, and around 15PSI at idle.

Link to comment
Share on other sites


where did you plumb it in ?

I fitted a T-piece in the hole where the warning-light sender fits. Warning-light sender then screws into one leg of the T-piece, the other leg has a 1/8BSP thread for the nipple that takes the small-bore Nylon pipe to the gauge.

(I put some spiral cable-wrap round the nylon pipe over the length thats close to the turbo & exhaust-downpipe as the idea of the pipe melting and spraying hot oil all over the turbo is unattractive).

Link to comment
Share on other sites

Don't forget a oil pump does not create pressure, it only creates flow, the pressure is created by the oil clearances between the moving parts. I am guessing the pressures you gave us in Bar. 6-8 Psi seems in the region of 0.5 Bar which puts the pressure exactly where the switch will put the light on.

75 Psi hot/normal running temp is 5 Bar that don't sound right , I can see this happen when cold and running the wrong viscosity oil.

Link to comment
Share on other sites

75psi at 4000rpm doesnt sound that unusual to me, my Audi produces 5 bar oil pressure by around 3-3.5k once hot, and its PRV opens around 6bar.

The odd bit is the suggestion that the relief valve is supposed to open at 4 bar. If it opens at 4 bar, and the engines producing 5 bar, it suggests its jammed closed. But if its jammed closed, surely it couldnt then cause low pressure at idle. I guess it could be jammed slightly open. Enough to cause low oil pressure at idle, but not enough to stop the pressure exceeding 4bar at high RPM.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy