Oil light comes on at idle after driving at high speed

[astroboy]

My 1982 Vanagon 1.6L Diesel started acting strange, so I decided to check the compression. The front most injector well was found to be eroded substantially by the injector and down to 200 psi while the two pistons at the other end of the head were at 475psi with the other one 400psi. I bought a new head and installed it with new shields! After I got everthing back together, timed etc., I did a test drive. Everything seemed back to normal with the engine running smoothly. I then made a longer trip at 60 mph on the freeway. When I was about 60% of the way to my destination, the engine started heating up. When I got off the freeway, the oil pressure light went on. I started it and if I kept it rev'ed up a bit the oil pressure light did not come on.

On the way back to home I went about 40+ mph. When I got back home, the oil smelled bad and did not look good (looked like a lighter grade oil). I changed the oil and filter. As long as I drive locally at lower speed, the engine does not over heat and the oil pressure light does not turn on.

I previously (maybe a couple of months ago) had measured my oil pressure and at idle it was about 11 PSI and reved up some it went to about 70 psi. Yesterday I again got on the freeway and had a hot engine again and stinking oil. After it had cooled down and driving on city streets it ran well and temperature was where it always is, and the oil pressure light did not turn on at all.

Does this sound like the oil pump is going? That does not look like too big a job, but probably messy (like everything else about this engine).

Thanks for your advise in advance - John

[82vdub]

To test the oil light/sensor system, etc, put a mechanical gauge in it and read what that says. Compare those numbers to what the Bentley manual says is for normal oil pressure. If it's within spec, then look at the pressure sensor and/or gauge or the grounding on the oil control system, or the controller itself.

As for water temp, are you sure you aren't getting combustion gasses into the coolant system? You should be able to start the engine from sitting overnight, and if you have pressure within 30 seconds in the coolant system, then you're getting combustion gasses into the coolant.

Or, do you have the proper coolant flow to the high mounted jug that removes all air from the system? If that line does not let coolant flow through it into the jug, air will get trapped and lead to higher coolant temps.

Have you ever had the intermediate shaft bearings replaced? These wear and are a common source for low oil pressures (among other things).

See what you can determine on these and repost results.

[bowditch]

Hey John, do you remember what you figured out on this one? I'm having the exact same problem with the 82 vanagon diesel

[greg lousy]

the original post is pretty old. There's two main symptoms in it - oil light and overheating. So I'm not sure what you mean by the "exact same problem". More information about what your problems are would be helpful here