1995 Jimmy oil pump problems

[DrPablo]

Hi,
I have since 3weeks a GMC Jimmy 4.3l V6 165kmiles from 1995. I changed the oil with Castrol GTX 10W30. It works great but now in the morning when it is cold the needle from the oil pump gauge gets up to 80. When the engine is warm it is on traffic lights at 40 and when I am driving at 60.
Is my oil pump going to die?
Does someone have the same problem? Do I have to change my pump? I don´t want to ruin my car, I like it and I will do everything to stay alive as long as possible.
(Sorry for the bad english, English is my second language, I am from Germany)

 

[Molson02536]

Hi,
I have since 3weeks a GMC Jimmy 4.3l V6 165kmiles from 1995. I changed the oil with Castrol GTX 10W30. It works great but now in the morning when it is cold the needle from the oil pump gauge gets up to 80. When the engine is warm it is on traffic lights at 40 and when I am driving at 60.
Is my oil pump going to die?
Does someone have the same problem? Do I have to change my pump? I don´t want to ruin my car, I like it and I will do everything to stay alive as long as possible.
(Sorry for the bad english, English is my second language, I am from Germany)

Worn old pressure sending unit and the recommended Oil is 5W30. The 10W30 may be to thick when engine is cold which would give you a higher oil pressure reading.

Try going back to the 5W30 weigh oil and if that does not fix your oil readings, replace your oil pressure sending unit. Be careful that you install the right oil pressure sending unit, one of just for a low oil pressure light and the other is for a gauge like the one you have.

The readings you gave are correct for oil pressure and no worries, you can chose not to replace your sending unit for now if there is no oil leaks but if you would like to replace it.

The oil pressure sending unit is located at the back of the engine behind the distributor. PINA to replace.

Good luck and keep us posted.

 

[DrPablo]

two weeks ago when the weather was mild (low 40s) I replaced the oil with castrol GTX high mileage 5W30. The engine oil was hot, I was driving at least 20min on the highway so that I get all the bad things out of the engine.
Now the temperature is drop to 2-9°F at night and during the day it hardly goes to 33°F. When the engine is cold it will still go to almost 80psi and when it is warm it stays at 60psi. So i think the oil sending unit is bad.
I am deciding to replace it next spring when I can work outside again.
Does anyone has experience with a good oil cleaning fluid?

 

[Molson02536]

two weeks ago when the weather was mild (low 40s) I replaced the oil with castrol GTX high mileage 5W30. The engine oil was hot, I was driving at least 20min on the highway so that I get all the bad things out of the engine.
Now the temperature is drop to 2-9°F at night and during the day it hardly goes to 33°F. When the engine is cold it will still go to almost 80psi and when it is warm it stays at 60psi. So i think the oil sending unit is bad.
I am deciding to replace it next spring when I can work outside again.
Does anyone has experience with a good oil cleaning fluid?

I use http://www.marvelmysteryoil.com/ in my oil 500 miles before i change my engine oil and filter. It cleans out any carbon and sludge that is in the engine, the other product you can use also is http://www.seafoamsales.com/.

The Seafoam will also do the same thing but I would only run the engine for about 10 miles. The Seafoam is thinner then the Marvel Mystery oil. Try using the Marvel mystery oil first and hope will help clear up your bed sending unit.

Good luck and keep us posted.

 

[Brainchild69]

I just bought a 1995 Jimmy a week ago. I have seen a similar problem to Dr.Pablo's;when the oil is cold the pressure is high, but when the engine warms up, the pressure drops to almost none at idle, and the 'check gauges' light comes on. I am pretty sure it IS the oil pump because the engine sounds like it doesn't have enough oil pressure. How hard is it to change the oil pump on one of these things? Also, how much more work is it to put a high volume pump in and is it worth the extra work?
Thanks.