1990 Jetta oil pressure.......?

I'd be surprised if it were for high oil pressure, most likely low oil pressure. Oil pressure is highest when engine is cold and will drop off when hot. In GM cars 15 PSI at idle when hot is considered OK. If the buzzer comes on when hot at idle it may indicate worn bearings. If you used the incorrect weight of oil it can cause low oil pressure.

I assume that there is not an oil pressure gage.

Buzzer = low pressure

your car actually has a dynamic oil pressure sensing setup, which uses two sensors, one in the oil filter housing and one in the head. It checks for a certain pressure at all times and a higher pressure above

3000 RPMs. The circuitry for this is built into the instrument panel. You could have a bad sensor (or two) or a bad IP, or an actual low oil pressure problem. If you haven't already you might want to post to rec.autos.makers.vw.watercooled someone there can probably point you toward a web site with more information on this system and/or how to defeat it entirely and install a mechanical gauge.

As a reality check you may wish to just install a gauge at the head and see what you pressure really is, to make sure that you don't have a problem. Rule of thumb is 10 psi/1000 RPM although I believe VW has their own specs which are published in the Bentley manual.

good luck,

nate

Almost forgot... VW engines of that era like thick oil, you should be using a xW40 or xW50 oil. 10w30 does not cut it on a VW especially if it has some miles on it.

nate

Scott Buchanan wrote:

Now that's interesting. I threw in 5w30.

Am I actually doing damage by using this oil, or is it just setting off the oil pressure sensor?

Probably not doing any damage but I know that my old 16V would exhibit some lifter clatter (but not light the light) when hot.

nate