Motor Oil Type
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#33
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Year: 1989
Model: Comanche
Engine: '91 Comanche 4.0 H.O.
In my XJ, I have 332,67x miles, and I've been running straight 30W Royal Purple, before that, I ran 30W Valvoline. I run the single viscosity because my truck sees lots of towing/wheeling and I don't like the thinner oil, it doesn't cling or lubricate as well, it has a lower shear point than the thicker oil.
#34
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Year: 1993
Model: Cherokee
Engine: 4.0
Where exactly did you hear that? Most oil brands list 5000 miles or better, and many vehicles specify 7500 before oil and filter changes. And oil filters become more efficent with age, to a point
#35
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Year: 1995
Model: Cherokee
Engine: 4.0 I6
And to the efficiency, think flow. 3000 miles later and your filter has alot more crap blocking it.
#36
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Year: 2004
Model: Grand Cherokee
Engine: 4.0L
I only drive My XJ about 3k per year...but I change the oil about every 6 months..a 1/3 of those miles are towing a boat.
It's not just the miles but the time it's in there for me..plus I like doing it.
I write the miles and date on the filter with a sharpie as well..
10w30 Castrol Synth and a Purolator Pure One filter - since I bought it in 03
pd
It's not just the miles but the time it's in there for me..plus I like doing it.
I write the miles and date on the filter with a sharpie as well..
10w30 Castrol Synth and a Purolator Pure One filter - since I bought it in 03
pd
#37
☠ CF Sheriff ☠
In my XJ, I have 332,67x miles, and I've been running straight 30W Royal Purple, before that, I ran 30W Valvoline. I run the single viscosity because my truck sees lots of towing/wheeling and I don't like the thinner oil, it doesn't cling or lubricate as well, it has a lower shear point than the thicker oil.
A straight weight oil is WAAY too thick to lubricate at engine start, you're effectively overworking your engine and starter when you first start your vehicle, and causing unnecessary wear. I'd say 90% of engine wear occurs at vehicle startup. This is the entire reason multi-viscosity oils were invented. Once the vehicle warms up, a 5w-30 oil will act EXACTLY like a straight 30 oil.
As far as the oil "clinging", it's not the key. Oil on the surface of parts does not lubricate, the key to lubrication is FLOW between the parts. If the oil is too thick to flow (eg: at startup), you're not lubricating the engine properly.
I will say though that the fact that you are using a full-synthetic helps your thickness issues at startup over mineral oil, but it's still too thick.
I always try to post this whenever this topic comes up. It's a little long and technical at times, but it is EXTREMELY informative and WILL change your opinion/view on the motor oil you use in your engine. Everyone should take the time to read it.
http://www.bobistheoilguy.com/motor-oil-101/
#38
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Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Why are we bringing a thread that has been dead for two and half years back to life? This one of the few topics to never bring up. NEVER start any of these topics:
1. What thermostat to run? (the correct answer is 195).
2. What is the best oil to run?
3. Should I get a "chip" for the engine?
4. What are the best tires for my XJ?
5. Who makes the best sounding speakers?
1. What thermostat to run? (the correct answer is 195).
2. What is the best oil to run?
3. Should I get a "chip" for the engine?
4. What are the best tires for my XJ?
5. Who makes the best sounding speakers?
#39
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#40
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Year: 1993
Model: Grand Cherokee
Engine: 5.2L MPI V8 (318)
you are sorely mistaken in your reasoning sir.
A straight weight oil is WAAY too thick to lubricate at engine start, you're effectively overworking your engine and starter when you first start your vehicle, and causing unnecessary wear. I'd say 90% of engine wear occurs at vehicle startup. This is the entire reason multi-viscosity oils were invented. Once the vehicle warms up, a 5w-30 oil will act EXACTLY like a straight 30 oil.
As far as the oil "clinging", it's not the key. Oil on the surface of parts does not lubricate, the key to lubrication is FLOW between the parts. If the oil is too thick to flow (eg: at startup), you're not lubricating the engine properly.
I will say though that the fact that you are using a full-synthetic helps your thickness issues at startup over mineral oil, but it's still too thick.
I always try to post this whenever this topic comes up. It's a little long and technical at times, but it is EXTREMELY informative and WILL change your opinion/view on the motor oil you use in your engine. Everyone should take the time to read it.
http://www.bobistheoilguy.com/motor-oil-101/
A straight weight oil is WAAY too thick to lubricate at engine start, you're effectively overworking your engine and starter when you first start your vehicle, and causing unnecessary wear. I'd say 90% of engine wear occurs at vehicle startup. This is the entire reason multi-viscosity oils were invented. Once the vehicle warms up, a 5w-30 oil will act EXACTLY like a straight 30 oil.
As far as the oil "clinging", it's not the key. Oil on the surface of parts does not lubricate, the key to lubrication is FLOW between the parts. If the oil is too thick to flow (eg: at startup), you're not lubricating the engine properly.
I will say though that the fact that you are using a full-synthetic helps your thickness issues at startup over mineral oil, but it's still too thick.
I always try to post this whenever this topic comes up. It's a little long and technical at times, but it is EXTREMELY informative and WILL change your opinion/view on the motor oil you use in your engine. Everyone should take the time to read it.
http://www.bobistheoilguy.com/motor-oil-101/
Thank you for posting this link. Before today I had always had my oil and filter changed by Jiffy Lube, and my engine has done just fine and ran just fine, but I never understood hardly anything about oil grade, viscosity, or how exactly temperature and start-ups effected my engine and the oil within.
#43
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Year: 1994.5
Model: Cherokee
Engine: Inline 6 4.0 HO
just as XJ Stryker declared back in Jan. of 2009, so I concur & bring this back to the land of living threads because I likes my Shell Rotella T6 15w-40 oils. So does my '95 XJ. She had her oil change for 387,000 miles today. This stuff every 3000 miles helps her L6 4.0l HO motor to keep chuggin' away & holding acceptable compression in all cylinders .
#45
i work at a shop and have tried just about everything from mobile 1, hight mileage, slick 50, 10w30, 5w30,...ect the best that i have found for a high mileage engine was 15w40 rotella T, its used in diesels, its thicker, i found out if you have any leaks(even small ones) synthetic oil will tend to leak faster because the molecules are bunched closer together, synthetic will also drain faster from you valvetrain than thicker oil, thus more noise and wear on cold starts..just my 2 cents
Does the 15w40 work well for winter months?
Last edited by Tabitha Fox; 10-01-2016 at 07:23 AM. Reason: Accidentally hit submit before finishing!