My Jeep looses oil pressure when the car is idling, and if it is idling too long the engine temp goes up past center and keeps climbing. I have had the water pump replaced 2 times and i believe the thermometer too. anyway i can diagnose the problem and fix outside the shop?

Low oil pressure will cause engine knocking at idle. Pressure climbs and properly lubes engine at higher RPM> Check your oil level.

Squealing may be caused by a loose/worn belt on the power steering system.

What is the make/model of the Jeep? What engine? Are you losing pressure completely or is it just low at idle? Many older Jeeps show little oil pressure at idle when the engine is warm. If you aren't hearing rattling like you are actually losing oil pressure, and the pressure comes up when you accelerate, you are probably OK.

OIL PRESSURE SWITCH-I'm not sure if this is the gauge sender, though. 1995 Jeep Grand Cherokee 4WD 4.0L MFI 6cyl The Oil Pressure Switch is located: Under hood, passenger side, lower engine area, above oil pan, mounted in engine block.

Oil pressure will drop at idle because the pump is driven by the engine. It should not go lower than 20psi. (I prefer to see at least 30) Very low pressure indicates bearing wear and pump replacement will not fix that.
Pressure may also be influenced by engine temp and if yours is getting hotter than it should, that accounts for a few psi as well.
Your water pump only needs replacement if it is leaking or the shaft bearing is loose. It actually will continue pumping even if both things are wrong with it.
Overheating at idle is generally caused by internal blockage of the radiator, bugs, or leaves packed into the front of the A/C condenser, or trapped between the condenser and the radiator. Your cooling fan must be operational as well. electric fans should come on at just above normal operating temp and the mechanical fan must not freewheel when the engine is hot (it has a fluid clutch or spring driven clutch that allows freewheeling cold , and locks up when hot).
If your thermostat is new, check that it is not in backwards (spring end goes towards the block) and that it is centered in the hole.
When adding coolant, always run the heater while re-filling to eliminate air pockets, and always make sure the thermostat has opened so all the coolant can be added (fill when running)
I am assuming that you have no other leaks or problems.

sounds like you have a plugged convertor

At idle, at operating temp is there any ticking from top end of engine? Are there any knocking noises brom bottom end?
If no noises, change oil and add some Marvel oil to clean out galleys. If that dosent work, change oil pressure sendingf unit. Also, if you have a mechanical oil pressure gauge, hook it up and take a direct reading. Oil pressure (in any vehicle) at idle should NEVER be less than 15psi. Generally in 4.0 jeep engines it's never less than 30, with a high reading at driving rpm of about 40-60! (but, you did not mention what engine you have)

If there is no engine noise associated with this ow oil press reading then replace the oil pressure sending unit on the engine, it is defective, this is common on all cars.

check the engine oil level... you could possibly need to replace the oil pump soon... if you do not live in a cold climate i would consider using 30 or 50 weight oil. do NOT use that in a cold climate as the oil is like molasses when it gets cold.
that's only temporary. one other thing to consider is a clogged oil filter... when was the last time it was changed ?

Robert

i had same problem and its just oil pressure sending unit its above oil filter just check it if you got some loose wire or somthing .........my problem was ;i had oil in conector i clean it and works jyst fine