I am doing some oil changes tomorrow in the XJ and the Grand Cherokee and was wondering if there is an option for oil to help the engine run cooler. I had 10w 30 in the XJ and I dont like it. I am thinking about 10w 40 with a lucas additive ( I know, I know.. bob the oil guy... blah, blah, blah) But I am thinking the thicker 10w 40 with the Lucas might help the engine run cooler and smoother. I have read good things about it. But I would like to see the engine not run so hot. It seems to hit 215 too easily and then drop down once the fan kicks on, but it just seems to run up to 215 and drop too often. Shouldnt there be a point were the engine reaches a consistant level?

 

Havoline 10-w40 with deposit shield. 17$ for 5 quarts at autozone.

Engine runs cool at 190. 60psi with load, 40 at idle. My father has used this oil since he bought it with 20,000 back in 2001 and it still starts and runs like the day he bought it. But it's mine now.

 

If the issue is particularly bad, you can also try installing an oil cooler onto the vehicle. Also, keep in mind that most oil 'additives' are snake oil...they really aren't going to do much at all. There ARE exceptions out there, notably Seafoam. It may be worth running a can through there before your next oil change. You probably have a good amount of sludge built up on your engine.

 

A thicker oil isn't going to help you run cooler.. and then wasting more money on Lucas isn't going to do it either. Creating more drag on your engine by making the oil pump have to work harder would actually increase the heat output rather than lower it.

If you know what additives actually are and use them for those intended purpose rather than thinking they are a magic cure-all. Lucas is really nothing more than a massive dose of oil thickening agents. It MAY help with some ticking noises when warm. But it WILL make cold start noise worse.

The Cherokee is originally designed to run at 210 degrees, so the fan kicking on in that neighborhood is the correct operation of it. But the dash gauges are notorious for being inaccurate. Have you hooked up a better sender and gauge, or are you going off the factory one?

Seafoam is a really good detergent. Because its kerosene.. Any kerosene will work just as well to clean the crud out of an engine, so will #1 diesel. Seafoam is another one that is WAY over-used. Remember what it is.. and you will be happy.

A better way to address this is to look at the cooling system. When the last time you have checked it? Is it properly operating? when was the last time you changed the coolant? Is your ratio of anti-freeze to water out of whack?? Remember that anti-freeze carries less heat than water.. A cooling system with too much anti-freeze will run much hotter.. Is your radiator and tranny cooler/AC condenser clear of debris,mud, cardboard, etc? How about the operation of your auto tranny?? If it is generating excess heat, it will raise the cooling system temps.
There is a coolant additive from Red Line called water wetter that will reduce cooling systems temps. It really works quite well.

 

I totally spaced it on Watter Wetter. That stuff works great.

 

^No need for me to elaborate, just count me in with everything whowey said.

 

As already stated, thicker oil causes higher temps. Thicker oil means higher pressure....higher pressure robs horsepower. Higher oil pressure does NOT equal better lubrication......more flow equals better lubrication.

If you want an engine to run its coolest, you need to concentrate on the cooling system, especially the radiator. The rad is the hardest cooling component to remove/inspect so it's the most often neglected. Pull the rad, have it roded out or replace it. Let's face it, the newest of our XJ's are almost 10 years old now with lots of normal build-up inside the rad reduces cooling efficiency. Start with the rad and go from there. Also, get a good aftermarket coolant temp gauge......factory temp gauges are a joke. Anyone that thinks the actual XJ coolant temp rises to 210F and just stays there is living in a dream world. Actual coolant temps constantly rise and fall due to varied driving and ambient temp conditions. The factory gauge just sits there at 210F because that's the way it was designed to function. I prefer the ScanGauge (OBD-II) as it displays coolant temp as seen by the ECU plus a lot more info and it just plugs in under the dash.

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

 

My guage doesnt just sit at 210 it moves to 213 or so and then drops again. None of my last few cars did this so it threw me off, thinking my engine was trying to overheat... excuse my ignorance or so called dream world. And I was not looking for a miracle in a bottle either, I have heard that people have had very good results from the lucas products. I appreciate the suggestions and help and will look at flushing the cooling system... that makes total sense... and I will check out this water wetter stuff as well.

 

Do you have an aftermarket temp gauge on your XJ or are you going by the factory gauge? To distinguish 210F from 213F would require a digital gauge, no? Like I said, most factory temp gauges are a joke and are purposely desingned to move very little (if at all) once the coolant has reached normal operating temp.

 

My temp gauge is actually pretty accurate to within +/- 5 degrees or so.

 

i'd like to ad in addition to checking the cooling system, you can also change the ratio of water/antifreeze in your mixture. normally, 50/50 mix is the most common, but changing the mixture to 60% water and 40% antifreeze will help a bit as well. i have a buddy in florida right now, and when he left michigan, his temps in his volvo shot through the roof. i told him to flush his system and fill it with nothing but distilled water, run it, drain it, and then put a mixture of about 70% water and 30% antifreeze, and he hasn't had a problem since.

and X2 on Water Wetter. when i first got mine some years back, it overheated like a ****. added some of that to it to help temporarily till i could go through the system, and it helped keep it cool.

 

Is that verified with another known accurate coolant temp gauge?

 

The guy comments about his temp and you challenge it... Why?

 

I have never purged a cooling system so I am a little nervous by it. Not as worried about emptying the coolant or refill more worried about the leaving air in the system and not being able to burp it.

 

He's not being out of line by asking, it was the first thing I thought when I read that as well. It may be totally accurate, we just want to know what method he used to confirm that.