what weight oil
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
.......so why use 10W40 or 20W50?.......and if u re-read Motor Oil 101 u'll see that 10W30 and 5W30 are the same vis at operating temp but 5WXX is a little thinner than 10WXX at less than operating temp, therefore it will flow a little quicker at start-up but be the same vis at operating temp.
Last edited by djb383; May 27, 2011 at 11:19 AM.
CF Veteran
Joined: Jun 2010
Posts: 2,117
Likes: 3
From: Ohio
Year: 1998
Model: Cherokee
Engine: 4.0 stock
Some people do. I guess it is a matter of your setup... if the engine is stock IMO it is better to go with what the factory says to go with. Nothing is stopping one from deviating... if they want to put a heavier weight in then it's their engine.
With many newer engines, the tighter tolerances and the more efficient oil pumps; The factory can suggest a lighter weight oil and still keep great pressure and flow. The lighter oil helps with efficiency also.
But on older engines built to the same spec as when they where first produced the tolerances might be a little more loose.... Using a lighter weight oil might be okay in some engines but might kill others. Just like using a thick oil in a modern engine that calls for a thin oil might be okay for some but kill others.
Now I'm not talking about not using 5W30 in the 4L I6. The manual says you can... but suggests it up to a temp of 60*F or lower where it says 10W30 would go from 0* on up the scale. I guess the bottom line should be depending on where you live and at what season your oil change is for would determine what weight you should use.
To a point it will. That is why there is an overlap of the 2 oils in the manual. The problem I had with the Bob guy was he said the 10W30 was too thick to pump when cold. If that was true you would start the engine and get no or very low oil pressure until the engine has warmed up. The fact is it does pump the thicker 10W oil just fine.
With many newer engines, the tighter tolerances and the more efficient oil pumps; The factory can suggest a lighter weight oil and still keep great pressure and flow. The lighter oil helps with efficiency also.
But on older engines built to the same spec as when they where first produced the tolerances might be a little more loose.... Using a lighter weight oil might be okay in some engines but might kill others. Just like using a thick oil in a modern engine that calls for a thin oil might be okay for some but kill others.
Now I'm not talking about not using 5W30 in the 4L I6. The manual says you can... but suggests it up to a temp of 60*F or lower where it says 10W30 would go from 0* on up the scale. I guess the bottom line should be depending on where you live and at what season your oil change is for would determine what weight you should use.
To a point it will. That is why there is an overlap of the 2 oils in the manual. The problem I had with the Bob guy was he said the 10W30 was too thick to pump when cold. If that was true you would start the engine and get no or very low oil pressure until the engine has warmed up. The fact is it does pump the thicker 10W oil just fine.
Thread Starter
Member
Joined: May 2011
Posts: 113
Likes: 0
From: jacks
Year: 98
Model: Cherokee
Engine: 4.0
Originally Posted by razor02097
Some people do. I guess it is a matter of your setup... if the engine is stock IMO it is better to go with what the factory says to go with. Nothing is stopping one from deviating... if they want to put a heavier weight in then it's their engine.
With many newer engines, the tighter tolerances and the more efficient oil pumps; The factory can suggest a lighter weight oil and still keep great pressure and flow. The lighter oil helps with efficiency also.
But on older engines built to the same spec as when they where first produced the tolerances might be a little more loose.... Using a lighter weight oil might be okay in some engines but might kill others. Just like using a thick oil in a modern engine that calls for a thin oil might be okay for some but kill others.
Now I'm not talking about not using 5W30 in the 4L I6. The manual says you can... but suggests it up to a temp of 60*F or lower where it says 10W30 would go from 0* on up the scale. I guess the bottom line should be depending on where you live and at what season your oil change is for would determine what weight you should use.
To a point it will. That is why there is an overlap of the 2 oils in the manual. The problem I had with the Bob guy was he said the 10W30 was too thick to pump when cold. If that was true you would start the engine and get no or very low oil pressure until the engine has warmed up. The fact is it does pump the thicker 10W oil just fine.
With many newer engines, the tighter tolerances and the more efficient oil pumps; The factory can suggest a lighter weight oil and still keep great pressure and flow. The lighter oil helps with efficiency also.
But on older engines built to the same spec as when they where first produced the tolerances might be a little more loose.... Using a lighter weight oil might be okay in some engines but might kill others. Just like using a thick oil in a modern engine that calls for a thin oil might be okay for some but kill others.
Now I'm not talking about not using 5W30 in the 4L I6. The manual says you can... but suggests it up to a temp of 60*F or lower where it says 10W30 would go from 0* on up the scale. I guess the bottom line should be depending on where you live and at what season your oil change is for would determine what weight you should use.
To a point it will. That is why there is an overlap of the 2 oils in the manual. The problem I had with the Bob guy was he said the 10W30 was too thick to pump when cold. If that was true you would start the engine and get no or very low oil pressure until the engine has warmed up. The fact is it does pump the thicker 10W oil just fine.
Seasoned Member
Joined: Jan 2011
Posts: 313
Likes: 0
From: Charlotte, NC
Year: 2001
Model: Cherokee
Engine: 4.0
think this subject is definitely a personal choice but with some good literature and others experience the decision can be a little easier to make and understand.
I would recommend 3 articles. While they are a little lengthy the info is, atleast I think, very interesting. Oil can be beaten to death but it is honestly the most important thing when it comes to protecting the internals of the engine.
#1: http://www.bobistheoilguy.com/cms/in...=article&id=84
#2: http://www.widman.biz/Corvair/English/Links/Oil.html
#3: http://www.engineoilinfo.com/index.htm
From my perspective you are doing the engine the biggest favor by using the lightest weight oil that can properly lubricate your engine. With your warm climate and low mileage I would go as light as possible and then work your way up if you notice any unnecessary knocking @ startup or running. A lot of people with tell you that 0w-30, 5w-30, or 5w-20's are meant for your hybrid but a high quality low weight is going to protect @ startup and full throttle better then there 15w-40 diesel oil from what I have researched. All that while improving gas mileage, not alot but everything helps..
The articles above are not bias towards any certain weight. #2 is more for the heavier weight even, so I am not selling my personal flavor koolaid. I think the test tube viscosity example on page 6 of the pdf speaks for it self..
I would recommend 3 articles. While they are a little lengthy the info is, atleast I think, very interesting. Oil can be beaten to death but it is honestly the most important thing when it comes to protecting the internals of the engine.
#1: http://www.bobistheoilguy.com/cms/in...=article&id=84
#2: http://www.widman.biz/Corvair/English/Links/Oil.html
#3: http://www.engineoilinfo.com/index.htm
From my perspective you are doing the engine the biggest favor by using the lightest weight oil that can properly lubricate your engine. With your warm climate and low mileage I would go as light as possible and then work your way up if you notice any unnecessary knocking @ startup or running. A lot of people with tell you that 0w-30, 5w-30, or 5w-20's are meant for your hybrid but a high quality low weight is going to protect @ startup and full throttle better then there 15w-40 diesel oil from what I have researched. All that while improving gas mileage, not alot but everything helps..
The articles above are not bias towards any certain weight. #2 is more for the heavier weight even, so I am not selling my personal flavor koolaid. I think the test tube viscosity example on page 6 of the pdf speaks for it self..
Seasoned Member
Joined: Jan 2011
Posts: 313
Likes: 0
From: Charlotte, NC
Year: 2001
Model: Cherokee
Engine: 4.0
think this subject is definitely a personal choice but with some good literature and others experience the decision can be a little easier to make and understand.
I would recommend 3 articles. While they are a little lengthy the info is, atleast I think, very interesting. Oil can be beaten to death but it is honestly the most important thing when it comes to protecting the internals of the engine.
#1: http://www.bobistheoilguy.com/cms/in...=article&id=84
#2: http://www.widman.biz/Corvair/English/Links/Oil.html
#3: http://www.engineoilinfo.com/index.htm
From my perspective you are doing the engine the biggest favor by using the lightest weight oil that can properly lubricate your engine. With your warm climate and low mileage I would go as light as possible and then work your way up if you notice any unnecessary knocking @ startup or running. A lot of people with tell you that 0w-30, 5w-30, or 5w-20's are meant for your hybrid but a high quality low weight is going to protect @ startup and full throttle better then there 15w-40 diesel oil from what I have researched. All that while improving gas mileage, not alot but everything helps..
The articles above are not bias towards any certain weight. #2 is more for the heavier weight even, so I am not selling my personal flavor koolaid. I think the test tube viscosity example on page 6 of the pdf speaks for it self..
I would recommend 3 articles. While they are a little lengthy the info is, atleast I think, very interesting. Oil can be beaten to death but it is honestly the most important thing when it comes to protecting the internals of the engine.
#1: http://www.bobistheoilguy.com/cms/in...=article&id=84
#2: http://www.widman.biz/Corvair/English/Links/Oil.html
#3: http://www.engineoilinfo.com/index.htm
From my perspective you are doing the engine the biggest favor by using the lightest weight oil that can properly lubricate your engine. With your warm climate and low mileage I would go as light as possible and then work your way up if you notice any unnecessary knocking @ startup or running. A lot of people with tell you that 0w-30, 5w-30, or 5w-20's are meant for your hybrid but a high quality low weight is going to protect @ startup and full throttle better then there 15w-40 diesel oil from what I have researched. All that while improving gas mileage, not alot but everything helps..
The articles above are not bias towards any certain weight. #2 is more for the heavier weight even, so I am not selling my personal flavor koolaid. I think the test tube viscosity example on page 6 of the pdf speaks for it self..
Seasoned Member
Joined: Jun 2010
Posts: 352
Likes: 0
Model: Cherokee
Just drove 625 miles in the Silver Jeep yesterday to fill her up with 585 pounds($2078) of Amsoil from Portland, OR distribution center. 20.3 mpg on way down, 19.3mpg Loaded on way back. Not bad for Spirited driving on I5 and I90 with bumper2bumper hour+.
CF Veteran
Joined: Dec 2010
Posts: 6,880
Likes: 0
From: Frederick, Maryland
Year: 1996
Model: Cherokee
Engine: 4.0 I-6 High output
CF Veteran
Joined: May 2011
Posts: 1,381
Likes: 0
From: EAFB, SD
Year: 1994
Model: Cherokee
Engine: 4.0 HO
Nothing wrong with running what the owners manual says only done a couple changes in mine but 10w-30 hasn't caused issues yet. It does freeze out here but right now its over 100 so yea. Oil gets changed every 3-5k. Should you run something different should I run something different who cares? Jeep said 10w30 and these motors don't seem to care all the way up to what 400+ thousand miles? I would be willing to bet if you took several 4l and ran 5w30 in some and 10w30 in others they would all go out about the same time. YOU will ALWAYS be the deciding factor on wear and tear on your motor. Your driving style makes a hell of a lot more of a difference than which oil goes in.
Sent by my pet chicken
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Joined: Apr 2011
Posts: 8
Likes: 0
Model: Cherokee
I had been using 10w40 Valvoline Durablend for about 4000 miles. Something about that oil blend regardless of the heavier weight made the engine very quiet. I'm finicky and wanted to try something else though.
I read all the stuff about lack of zddp in motor oil (...zzz) and decided to try the Valvoline 20w50 racing oil. Oil pressure went up just slightly, but engine noise went up tremendously (lack of flow) and acceleration went way down. It wasn't a pleasant experience by any means. So what if it has higher amounts of what's good for the engine if the lack of flow isn't there?
I then moved very briefly to Supertech 10w40. It's cheap, readily available dino oil. Can't go wrong. Engine noise and acceleration was about the same as the Valvoline racing oil. This unsettled me no matter how cheap it was.
Right now I'm using Schaeffer's 5w30. The engine is quieter and the flow has got to be better. Acceleration is easier and it doesn't feel as bogged down. Oil pressure is still in spec. I have a 95 Cherokee with 150k rough miles, no engine work.
Schaeffer's is expensive though. I may or may not keep using it. It seems I got the same experience from the Durablend and it's much cheaper.
Keep trying different ones until you find what you like, but I would lean towards lighter weight oil even with high mileage if you can get away with it. It just makes more sense.
I read all the stuff about lack of zddp in motor oil (...zzz) and decided to try the Valvoline 20w50 racing oil. Oil pressure went up just slightly, but engine noise went up tremendously (lack of flow) and acceleration went way down. It wasn't a pleasant experience by any means. So what if it has higher amounts of what's good for the engine if the lack of flow isn't there?
I then moved very briefly to Supertech 10w40. It's cheap, readily available dino oil. Can't go wrong. Engine noise and acceleration was about the same as the Valvoline racing oil. This unsettled me no matter how cheap it was.
Right now I'm using Schaeffer's 5w30. The engine is quieter and the flow has got to be better. Acceleration is easier and it doesn't feel as bogged down. Oil pressure is still in spec. I have a 95 Cherokee with 150k rough miles, no engine work.
Schaeffer's is expensive though. I may or may not keep using it. It seems I got the same experience from the Durablend and it's much cheaper.
Keep trying different ones until you find what you like, but I would lean towards lighter weight oil even with high mileage if you can get away with it. It just makes more sense.