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-   -   First trip to the mountains coolant and oil temps (http://www.jeepgarage.org/f108/first-trip-to-the-mountains-coolant-and-oil-temps-29465.html)

jeep2011 10-08-2011 07:40 AM

First trip to the mountains coolant and oil temps
 
Took the new overland up to the mountains this weekend, it sure is a mountain goat and can walk up any grade with confidence. I am a little worried about the temps the EVIC is showing though.

The driveway to the cabin is straight up and mostly a 15-20 degree grade. The climb is around 3 miles to the top and the temperature was 72 degree's. Had the Jeep in TOW/HAUL mode the entire time. The engine coolant was reaching 222-235 and the fans would kick in and bring it down right away, but the oil temp kept rising and would go as high as 242 degree's. I would have thought when the fans kicked for the coolant it would have brought down the oil temp as well. Isn't 242 HOT for conventional oil?

The trans temp stayed around 190 which was a lot less than my tahoe would be (220-230) for the same grade, but it didn't have the trans cooler.

johnpaul 08-01-2012 11:12 AM

Re: First trip to the mountains coolant and oil temps
 
Hi Did you get any answer to this, i am seeing the same thing.

brandont 08-01-2012 12:22 PM

Re: First trip to the mountains coolant and oil temps
 
Oil will (and should) get hotter than the boiling point of water in order to boil off any H2O in the system. I know when I raced I saw temps that were higher than that. If you do that regularly I would look into synthetics, or at least check into the oil you are using and find out what the thermal breakdown point is. Should be able to handle 240 in any case, but doesn't hurt to check.

johnpaul 08-01-2012 01:09 PM

Re: First trip to the mountains coolant and oil temps
 
Brandont, Thank you for the info. The dealer gave me a prepaid service contract to 100k so I will need to asked them what they are using. This happens ever day otw home in rush hour, its over a 100F here. Do you recommend a synthetic? Mobile 1 etc

brandont 08-02-2012 09:07 AM

Re: First trip to the mountains coolant and oil temps
 
That is a slippery topic. Hah hah! Seriously, opinions on oil recommendations run wide and deep. In the end the ‘best’ oil is going to be almost as individual as you are. However, if you want you can have your oil tested by http://www.blackstone-labs.com/ which would give you some indication of how your oil is doing. Only problem is you might only get to the ‘right’ oil after several oil change intervals. You can also read lots of info at http://www.bobistheoilguy.com/ and probably get more opinions than you will care to read.

Personally, I try to take care of my car but I just don’t want to invest that much effort. I always run synthetics and I do my oil changes regularly. I have been running M1 0w-30 fuel economy but I only have an 8mi commute and the winters get down to -20F. So for me, quicker warm up and cold start protection are my main issues of concern which lead to the 0w-30. On the Jeep I’ll probably follow the EVIC reminder (though I did change the factory oil early). I figure with a decent synthetic that should be good enough without figuring out which oil can be run for another 1k mi or which filter is 5% better. But like I said, which oil is ‘best’ is going to be a personal thing. I hope that helps more than it confuses!

andyh 08-02-2012 05:31 PM

Re: First trip to the mountains coolant and oil temps
 
None of those temps would bother me.

armoredsaint 08-03-2012 07:46 AM

Re: First trip to the mountains coolant and oil temps
 
Quote:

Originally Posted by andyh (Post 664906)
None of those temps would bother me.

+1

you are driving up and down mountains, you don't expect it to be the same as driving on flat pavement. ;)

hummer recovery team 08-03-2012 10:49 AM

Re: First trip to the mountains coolant and oil temps
 
A good synthetic oil is good insurance in my oppinion

Mongoose9400 08-03-2012 10:53 AM

All perfectly normal temps.


Sent from my iPhone 4S

Jeep_addicted 08-07-2012 11:57 AM

Re: First trip to the mountains coolant and oil temps
 
As all the others have stated these temperature are within the parameters of operation.

The things you need to look at are how often to you visit the cabin and subject he jeep to that type drive.

If you do this regularly then, like they suggested, would be to move to a synthetic oil and observe the same oil change interval

Or if you want to stick with conventional oil you may want to change your oll more frequently.


The other issue with these jeeps are that the transmission gear ratios are on the high side for the lower gear so even if you are travelling at a fairly low speed they engine speed has to be higher to spin the gear.

This to will contribute to the higher coolant and oil temps you are seeing.

I wish that both the 5.7 and 3.6 had a higher oil capacity by 2 quarts which could help in the oil temp department.

Doc_d 08-17-2012 08:18 AM

Re: First trip to the mountains coolant and oil temps
 
Quote:

Originally Posted by Jeep_addicted (Post 667010)
The other issue with these jeeps are that the transmission gear ratios are on the high side for the lower gear so even if you are travelling at a fairly low speed they engine speed has to be higher to spin the gear. This to will contribute to the higher coolant and oil temps you are seeing.

I think you have this backwards. Tall/high gear ratios will cause you to have lower engine speeds. Lower engine speeds (with high load) will cause the engine to run hotter. So manually shifting to a lower gear to keep the revs at say 2,000 - 2,500 RPM will actually improve engine cooling versus lugging along at 1,200 RPM. Higher engine RPM means less load and less fuel burned per revolution given the same amount of work. The higher engine speed also increases coolant and oil flow.


Quote:

Originally Posted by Jeep_addicted (Post 667010)
I wish that both the 5.7 and 3.6 had a higher oil capacity by 2 quarts which could help in the oil temp department.

The Hemi has a 7 quart sump. I already cringe when buying oil. I definately wouldn't want a 9 quart sump.

Jeep_addicted 08-17-2012 12:28 PM

Re: First trip to the mountains coolant and oil temps
 
Quote:

Originally Posted by Doc_d (Post 671667)
I think you have this backwards. Tall/high gear ratios will cause you to have lower engine speeds. Lower engine speeds (with high load) will cause the engine to run hotter. So manually shifting to a lower gear to keep the revs at say 2,000 - 2,500 RPM will actually improve engine cooling versus lugging along at 1,200 RPM. Higher engine RPM means less load and less fuel burned per revolution given the same amount of work. The higher engine speed also increases coolant and oil flow.




The Hemi has a 7 quart sump. I already cringe when buying oil. I definately wouldn't want a 9 quart sump.


You are right in a sense about the gear ratio (that is the way it should be in a higher gear and you are traveling at a high rate of speed)

I drive up hills daily and the 5 speed in this V6's sweet spot to upshift from first to second is 30mph

Once you hit second if you lose momentum and drop below 27 mph it will down shift back to first.

If the transmisson were geared lower then second gear would be able to pull the load that first gear has to now, but it would do it at a lower RPM and forward speed thus allowing the engine to run cooler as you stated above.

I usually slap the shift lever so it can upshift but if it is not doing 30 mph uphill it will not upshift to second.

Our WJ never did this because the tranny was not geared for economy like this one is. No other jeep from the past I have driven behaves like this; so I have to put the blame on the gearing.

There is no reason that a vehicle as sophisticated and as these jeeps have become behaves like a 1.6L 4cyl with a 3 speed automatic going up hill which is First gear or nothing.



As far as the oil goes if they came with synthetic from the factory then the oll change interval could be longer and it would balance itself out.

I used to own a 6 cylinder sedan that used 8 quarts of oil and My previous 6cylinder SUV used 7 quarts of oil both used synthetic oil from the factory and I alway filled them with Mobil One Extented Performance.

The hemi oil capacity should be 8 quarts

The pentastar oil capacity should be 7 quarts


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