Engine Oil

[Disco69]

Well, I plan on running Royal Purple in the engine. My big question is what weight to run. The FSM says to run 5W-30 up to 32 degrees and 10W-30 the rest of the time. Is this true? In the winter, should I run 5 weight and in the summer 10 weight? Keep in mind that I have 85000 miles on the engine. Isn't there one weight that I could run the entire year?

[boostlesstj]

i always run 5w-30 year round, i think i'm gonna bump it up on the next oil change on the cherokee

[jeeptj333]

same here 5w-30

[AKMark]

Careful putting synthetic in a motor with over 70K on it. I personally and a few others I know have had the oil pressure suddenly drop within 1K miles after switching.

Synthetics can cause sledge that normal oils leave behind to loosen up and clog things. Lucky for me and two of my buddies, we notice the oil pressure drop and quickly shut the motor down. I had to pull the pan on one and clean the big chunk of goo that had lodged in my oil pump. After that it worked fine, and it ran synthetics full time after that.

I do however know a few folks who have had this happen and not catch it, and it equaled totalled motors. So if you do this, watch the oil pressure gauge like a hawk for the next couple of oil changes.

I love synthetics and run them in pretty much anything that I get, however my new DD has 181K on it, I will keep running regular oil in that because I don't want to pull an oil pan in the near future.

[99TJ]

I swapped to Mobil 1 I didn't have a problem with my oil pressure. Just my experiance. And I'd go with Mobil 1, I don't think royal purple is worth the hype.

[rpiereck]

5W-30 year round, run Mobil 1 on 100k engine, no oil pressure drop or leaks. Royal Purple and Mobil 1 are the same class of synthetic oils, not 100% synthetic by the way. If you are willing to spend the extra money for synth oil go with Amsoil, which is the only 100% synthetic regularly available motor oil.

[boostlesstj]

if you do you oil changes regularly you shouldn't have sludge

[AKMark]

I have purchased many used vehicles, I keep up on stuff, but don't know about the previous owners. I had a guy that had tons of reciepts and lists of what he did when, but after a short ownership period, I found I think he falsified stuff, because some parts were original although he said he had replaced them.

I also have worked at a Dealership and know if I had to stand behind my work, I would never recommend synthetics to anyone with over 70K without a stern warning, and something stating that if the motor quits within the first year and I find sludge clogging to be the culprit, that I'm not at fault.

[akhillbille]

I run what the factory calls for in every vehicle. I run synthetic valvoline in the xj, regular valvoline in the neon and cummins tested and designed valvoline blue in the dodge. I used to change weights in the cummins to 0w40 in winter and sometimes 5w40 but now I just stick with 15w40, With oil pan heaters running the thinner oil just didn't matter.

[reeferman]

5w30 Maxlife 220,000+. It does slow down the oil leaks, Bin running it sense 2000 and have had no problems.

[Bunker89]

I run Royal Purple 5W40 in the winter, an Royal Purple 5W30 in the summer. As u guys probably know the thinner Viscosity of the 5W40 helps with drastic negative temp up here, i've had no issues an my TJ runs like a champ.

[The Bronze]

I run Royal Purple 5W40 in the winter, an Royal Purple 5W30 in the summer. As u guys probably know the thinner Viscosity of the 5W40 helps with drastic negative temp up here, i've had no issues an my TJ runs like a champ.

I thought I knew that 40w is thicker than 30w. :cool:

[The Bronze]

Unless you switch from a Non-detegent containing motor oil to one that contains some variation of it (this covers most oils) you shouldn't have any issues. You have been able to swap non to synthetic to non for years without problems. During cold weather, I would not run an extended oil change ritual due to fuel dillution of the oil due to cold starts (less of an issue with light duty vehicles produced around 2000-cold vehicle quick closed loop).

[akhillbille]

I do a prolonged oil change ritual. After talking to a few oil burner techs who do testing in canada with just as cold temps as us I'll keep doing it. They seen no problem with it. I change my filter twice a year roughly and oil about once a year. And the filter change is actually less than recommended.

[The_Ronster]

I run the Castrol Synthetic Blend which has always worked well for me. I dont change weights between the summer and winter and it works just fine for me.

[The Bronze]

I did factory schedules oil changes on my cummins, but my oil change recommendation are based on gasoline fueled vehicles. Hundreds of oil changes with runny-gasoline smelling oil makes me appreciate fresh fluid. Of course those with long commutes like Nate can rest easier.