I just got my 2001 Cherokee Sport about a month ago and based on what ive done none of the fluids have been changed in a while. So i was wondering what brand oil would be good for a high mile engine 170,XXX and what kind of filter. I changed the coolant and it was a muddy water color, changed it and just turned to that nice murky color again. I had to pull the lower radiator hose to drain the fluid because my petcock is stuck, anyone know how to get it out to replace?

-Thomas

 

You might want to flush that rad, I would just use a store bought radiator flush, In the forums I see a lot of different ways to do it, some like to use vinegar, most who do it say don't leave it in overnight, some say don't leave it in more then two hours, some say follow up by flushing with baking soda to neutralize the acid. Some say it won't hurt anything, but some say it's not good for Alum parts. Do a search on Radiator Flush on this forum and you will get some great solutions.

 

I use 10-30 castrol syn. blend with either a mobile 1 or mopar for the filter. As for the flush id say spend the 7-10 dollars and buy the flush/cleaner for your local parts store. If the colour keeps looking brownish you either have a very dirty cooling system or possibly blown head gasket and its allowing oil to get into the coolant system. More commonly its coolant gets into the oil making the oil look like chocolate milk but i have seen where its oil getting into the coolant, so youll want to see if your losing more oil then normal. To do a coolant flush correctly youll need to remove the thermostat so its 'free' flowing and thatll get all the dirt out, so id recommend getting a new thermostat and gasket, unless youve changed the thermostat resently then id reuse the old one and just change the gasket.

2¢

 

Whenever you change the coolant you should either run a 50/50 mix of 1L vinegar and 1L water for 15 mins at idle (enough to get it warm and circulate) or a regular flush.
After the flush, run water through it for about 15 mins again and drain.

Then put in your standard coolant mix. Use distilled water if you have to mix water in.
One of the big problems with cooling systems is people using tap water. It produces calcium scale and other nice stuff in your radiator. You should also replace the Thermostat. Stant Superstat, 195*.

Oil:
If you are going to run a standard oil it is highly recommended to run a ZDDP additive (see 5-90s post in the lifters thread). Another option is to run Diesel oil, though these are usually 40 weight oils (fine for my old jeep). If you want to go the more expensive route, Amsoil makes a high zinc formula. Mobil 1 High mileage full synthetic is SL rated and should be fine for the cam also. This is available in 30 wt and up to 50 wt. Usually ~25 for 5 qts at walmart.

 

Brand isnt really a big deal with oil, just run some decent synthetic in it. I've always ran Mobil 1 - 10w-30 with a NAPA gold series filter and changed every 5-8kmi.

 

If a higher mileage engine has never ran synthetic oil sometimes it will cause a leak, from what I hear. Ive always just ran the regualar dinosaur oil in mine. I started putting a quart of lucas in there and the engine quited down dramatically. I cant speak from expereince but a lot of people will (and Im surprised no has yet) say not to put syn oil unless you have been doing it all along.

Thats just my 2 cents as well

 

I put semisyn in mine at 206000. It leaked already, and hasnt gotten any worse from what I can tell. May of even slowed down a little.
Next change is gonna be dino though. Until I can find a good synthetic diesel oil that doesnt cost my left arm. Rotella is SM rated and doesnt have the right amount of zinc so thats out of the question.

 

Dont quote me on this but I believe the issue was if you ran synthetic then switched back to conventional your seals contracted and caused a leak, as I understand it synthetic causes them to swell and perhaps even leak less.

Someone who has switched to synthetic later in their XJ's life could pipe up here since mine has had synthetic since its first oil change.

 

Well thanks everyone. I take all this into account.

 

I would very much love to hear about this too, Im always up to spend extra money at oil change time

 

I run synthetic in both my 88 Jeep and 94 truck the Jeep motor has 136000 miles on it and the has 100000 plus on it I don't see any leaks. Now I don't if the po used synthetic in it or not.

 

I use Royal Purple in both my 96 and my 97 both have standard transmissions. The 96 has 271,000 and the 97 has 219,000. They both get 19 to 20 mpg or more (the 96 usually gets around 22 mpg) that's on straight gas, no ethonal. I've never seen a drop of oil in the driveway from either of them.

 

ironically i am quoting you and yes your right switching to 'full synthetic' then back to conventional will make it leak, because of the different additives each one uses switching back and forth will cause it.

 

I don't want to jump too deep into the oil conversation; always so much conflicting information and down right bad information. Run what you want, but the 4 main things I recommend are to make sure you're running the proper weight for your climate, keep up with oil/filter changes, don't run a FRAM oil filter, and listen to the advice given about zinc.

For the zinc either use an additive, diesel oil, or high mileage oil. I don't prefer the additive because it's so thick when you pour it from the bottle (I'm referring to the STP Oil Additive in the blue bottle), but I'd be ok with that if someone could confirm to me that it mixed well with the oil and wasn't so thick after running for a bit. Personally I run Rotella T Synthethic 5W-40 (I'm at 165K miles on my '92). It's a diesel oil.

As for the radiator petcock, I wouldn't mess with it. You were better off by pulling the lower radiator hose because often times when you pull the petcock on a stock radiator with the plastic end tanks, it will forevermore drip.

 

Personally, I've always used Castrol GTX, and now I use GTX High Milage with a quart of Lucas Oil Stabilizer with a K&N Gold oil filter. I've used Lucas for years now, and as far as I can tell it mixes with your regular oil just fine, when I pull the drain plug at oil change time, I can't tell it's been added, the only time I don't run it is in the winter here, because it gets COLD, and that stuff is about the consistancy of honey.
After reading everyone else's posts about synthetic and semi synthetic, I think I might give it a shot at the next change, more than likely stick with Castrol, but may try Mobil.