My oil pressure gauge is acting strangely. On start up it reads 0 for about 10 seconds then rises to about 25 PSI.As I increase the RPM the gauge drops to almost 0 them just fluctuates around 5 PSI.
I changed the sender but it has no effect. All wires and grounds check out fine, the engine runs well and the water temperature is normal on long runs.
is the gauge repairable? Any suggestions on the issue

 

You should check your actual oil pressure. Temporarily hook up a mechanical pressure gauge and see what you get. The problem might be a sticking pressure relief valve in the pump. Of course, if the pressure shows normal on the temporary gauge then the gauge is probably a good bet.

Dave

 

I had a bit of doubt on the OP of my lump. Reading real low! But, I felt a bit better as the hydraulic valves remained quiet signifying OP was OK.

I went shopping for a mechanical guage. surprise, no luck. I bought an after market Sun Pro kit. Plumbed it in and sure enough, OP was fine. Now my kit for diagnostics..

NOS sensor via .David Boger and all was well. The Sun Pro sensor was far more robust...

Carl

 

what may be sticking could be a spring valve at the oil filter Head and this is being mirrored by the gauge and reflected at the gauge. Don't assume it is the gauge.

Talk to member Sanchez about it. He can explain better than me.

the oil filter Head is an aluminium casting bolted to the passenger side of the engine block in all XK engines, The oil filter screws to it. it is removable after you drain the oil but you need a new gasket in advance to reinstall it. All oil filter heads have a spring pressure valve that sometimes gets stuck with age and crud causing apparent low oil pressure or no oil pressure at all.

these oil filter heads come in different shapes and the oil filter attaches to them at different angles depending on the year of the car, so be sure to get the correct gasket in advance. Otherwise after removing it, clean it in gasoline especially the oil orifices or passages, the spring. the pressure valve, etc.

We always replace the Sender, the gauge, and we spend days checking the wiring. when all that was needed was to clean the oil filter head and the spring valve.