Oil light & Thermostat

I have a disco 300td which now (no thanks to Equicar, the bastards) has a replacement driver's seat. Pheew, got that one off my chest..

However, my other problem is still the oil light coming on, but intermitently. Could it be that the oil guage switch AND the thermostat are buggered?

ie. if the oil thermostat doesn't function properly will it effect the heating system, and, the temperature guage? Often, the temp guage doesn't register a change even after a long run, and often the heating doesn't seem to work well-it seems to coincide with the oil light coming on?

oil and cooling systems are two totally seperate systems so a knackered thermostat wont cause the oil light to come on.

Check the coolant level.

A thermostat that is stuck open will cause the engine to run cold and therefore no heater. Very low or no coolant will cause the gauge to read cold and no heater and when it gets hot enough, the oil light will come on due to the fact its so hot, the oil will be like water, if its got to that point then usually the engine is knackered!!!

The oil warning could be something as simple as a faulty pressure switch or low oil level, or could be a terminally ill engine. Check the oil level first, if thats ok, change the oil pressure switch, if its still the same then you'll need to check the oil pressure with a gauge.

Sorry, I should have written oil thermostat..... though it also needs a new cooling system thermostat to fix the heater problem.

I guess it's going to be a faulty switch as it will goes on/off at all times regardless of how long it's been running - it's never consistent.

Thanks