ASAP..Oil Pressure Past 80???

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bzdel2441

NAXJA Forum User

• Oct 31, 2004

• #1

I just bough a new 89 4.0 MJ last weekend and I noticed that when I was driving it home it had an oil pressure at almost 80. Now I havent drove it all week today i just changed the oil and started it up and now the oil pressure is past 80. It doesnt sound like it is having and problems, is there any was I can really tell if the oil pressure is really 80+? Please let me know?

Thanks
Chris

 

Eagle

Lifetime NAXJA Member

NAXJA Member

Location

Terra Firma

• Oct 31, 2004

• #2

It is possible that the oil pump relief spring is bad, but it's unlikely that an '89 would have a pump and bearings capable of producing and maintaining anywhere near 80 psi. More likely the sender is faulty. They are notoriously inaccurate even when functioning "properly."

Best check is to remove the sender and hook up a known-good mechanical gauge. If you don't have a mechanical gauge, AutoZone sells the sender for $11.99

 

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bzdel2441

NAXJA Forum User

• Oct 31, 2004

• #3

I dont know if this has anything to do with it but I also checked just check teh dip stick and it is on just a tad above ADD. I know i put six quarts, because I have a six empty bottles, whats going on with that?

Also I have a 92 XJ with a halfway accurate gauage would that swap into the 89 cluster?

 

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bustednutz

NAXJA Forum User

Location

Virginia Beach

• Oct 31, 2004

• #4

Go to Autozone and get a new sending unit. They're cheep and very easy to install. That will fix the problem most likely. I had the same issue on my 96.
They install down by the oil filter housing.

 

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bzdel2441

NAXJA Forum User

• Oct 31, 2004

• #5

bustednutz said:

Go to Autozone and get a new sending unit. They're cheep and very easy to install. That will fix the problem most likely. I had the same issue on my 96.
They install down by the oil filter housing.

Click to expand...

Do you think it would be safe then to drive the truck 5 miles down the street to there? I could always walk if I had to. Is there any other way to tell if my oil pressure is really that high or its just a mechanical/electrical problem?

 

old_man

NAXJA Forum User

Location

Loveland, Colorado

• Oct 31, 2004

• #6

The only thing that too high oil pressure can screw up for the most part is to explode the oil filter. 80 lbs is not unusual at a cold idle, so you should be fine driving it to check it out. Like the man said, the problem is most likely a bad sender.

Do this check. Turn on the key without starting the engine. Does it read 0? If it reads full scale, you have a bad sender or wire. If it reads 0 then goes up after the engine is running, you most likely have a bad sender.

 

Eagle

Lifetime NAXJA Member

NAXJA Member

Location

Terra Firma

• Oct 31, 2004

• #7

You cannot interchange either the gauge or the sender from a 92 XJ into an 89. The polarity is reversed, and the senders have a different ohm range.

 

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bzdel2441

NAXJA Forum User

• Nov 1, 2004

• #8

old_man said:

Do this check. Turn on the key without starting the engine. Does it read 0? If it reads full scale, you have a bad sender or wire. If it reads 0 then goes up after the engine is running, you most likely have a bad sender.

Click to expand...

So I turned the key and it went to about 40ish.. Then once I started it it went past 80...So bad Oil Pressure Sending Unit?? Can I get them at any auto parts store or is the dealership my best bet?

 

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bustednutz

NAXJA Forum User

Location

Virginia Beach

• Nov 1, 2004

• #9

Autozone, Parts America, any auto parts store can hook you up.