perez1989

I just changed the oil on my 89 Jeep, got some Quakerstate 20W-50 and now it sounds like a diesel. Oil pressure is at 80 when it use to be 60. What oil should I put in it?

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1989 Jeep Cherokee Laredo
4.0L Automatic 4wd

jmm0122

I run 10w-40 unless 10w-30 is on sale.

96_xj

DO NOT RUN ANYTHING THAT IS HIGHER THAN AN xxW-30 the -30 at the end of the oil marking is what viscosity it is at operating temp. The reason it sounds like a diesel is because your oil is not viscous enough at operating temp.

some people run a diesel oil due to the zinc content in the oil is great for our flat tap cams.

run a 10w-30 or preferably a 0w30...

The 10w- or 0w- in front means what viscosity it is at on start up (32* industry standard). 10w is farther from the proper operating viscosity on start up, 0w is closer to operating temp viscosity on start up, providing better wear protection on start up.

It is not going to do anything to harm your engine running a 0w-30 infact it will help it. where as a 10w-40 or a 20w-50 will harm your engine.


also do not add any engine additives. They do not do your engine any good. they are a bandaid to an underlying problem.

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hard work and respect get you nowhere in todays life... what a shame maybe someday society will become less selfish

selfless over selfish

rich

10w30 or 10w 40 oil,some guys say 15w 40 or 20w50 thats fine if your motor is wore out that much to need it,If the oil is too thick for the motor it will chatter terrible .Castrol,mobil mopar oil all good to use

rich

For zinc just add a can of stp oil treatment,its the same thing.(read the bottle first before you say anything stupid please).I m just saying so we dont have a post full of uninformed posts.

perez1989

Ok thanks for the information. Gonna have to change the oil again today.

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1989 Jeep Cherokee Laredo
4.0L Automatic 4wd

whowey

Op... One of the BIG considerations for your oil weight, is your intended usage and the environment you live in.

Seeing how you live so far south, there is absolutely no reason for you to run anything with a 0W-xx. A multi-weight oil in such a viscosity is intended for folks living in the northerly climates where we see days when the starting temps are close to 0 degrees.

Yes... the 0,5,10,20,30 in front of the w is the cold weather viscosity. But its based on 0 degrees. An oil with a 10w viscosity is close to the same viscosity of a SAE 10 at 0 degrees. The advantage of this is in cold start conditions the oil flows fairly quickly. And a 10w is less viscous than a 20w oil in those conditions.

Now there are other considerations to look at. As your oil ages in the engine. Some of the additives break down and are able to do less work. Multi-weight oils(10w-30, etc.) have an additional additive class called viscosity modifiers in them. A single weight oil (SAE 30) do not carry much if any vicosity modifiers. And oils with a larger spread on the viscosity (5w-40,etc.) have a larger percentage of these additives than oils with smaller ones(5w-20). The oils with the large spreads will tend to break down more quickly due to this.

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trans_am7935

wow this thread is awesome....and at the same time way over my head. i use 10w-40. i like it the best. i live in California where it is always hot so i like the little heavier weight.

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perez1989

Well changed the oil today and now she sounds back to normal. Had to get the 10W-40

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1989 Jeep Cherokee Laredo
4.0L Automatic 4wd

djb383

http://www.supramania.com/aehaas/

Read some motor oil facts, not fiction, in the above link. The lower the first number, the better it is for your engine. 80 psi is just robbing horsepower. Motor oil myths are already prevalent in this thread.

The Black

So far I have read Motor oil 101 to 104. Fascinating info. Thanks for the link.

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ki4dmh

I use 10-30 in all my vehicles

djb383

5W30 would be better as it will flow faster at less than normal operating temp and is the same vis as 10W30 or straight 30 at normal operating temp.