Diesel engine oil & coolant temps

[Jeeper6]

Hey all...Just got back from the inaugural road trip with my "new" 2015 GC towing my van....temps too high imo...

[drover]

My oil temp when towing my rig sort of float around the 109/112 on the flat stuff with boot in for hills, headwinds etc it can go up as high as 120 on the big arse stuff like around Tumbarumba, Tranny will just hang around 92 mostly, even when hill climbing might jump a degree or 2, coolant I have no idea really but the gauge never seems to move off the centre mark..... when oil gets to 115 I will knock of the AC though to cut some load and heat, not very often needed......... normal highway at 30 deg ambient, oil at 105, tranny at 90 ............. best for keeping stable temps ever this vehicle..... ECB bar fully open for air flow, no lights or stuff to impede.

I have fitted fly screen behind the grill which keeps out bugs, seeds, grass and feathers from getting into the coolers, once they work their way between the cooler units Radiator/AC/Precooler you have to pull them out the clean, done it once, years ago never again.... was like a carpet jammed between them made up of wings, bugs.seeds and gunk.

[Surnturf]

Last trip was Adelaide to Kimberlys
Tow 2.7t with rooftop tinny at 96kph
Engine Oil 105c Trans 92 , oil might creep up to 109 if climbing hills but quickly returns, all the time with A/C running

[Jeeper6]

Thanks for the feedback..appreciated. I am concerned as the temps were running much higher than the previous Jeep. the last one would run mostly at 104 oil and 94 coolant even when towing....and was very steady.

The oil temp the other day hit 122c going up a smallish but long incline heading to Kenilworth, I was not pushing it either, so backed off a bit and it began to fall a degree or two...then mostly moved between 110c and 115c. At 100kmh on the Bruce Highway it was creeping up again to 120c so backed off to 90kmh and it fell again. Coolant got to around 110c..mostly sat between 105c and 110c but varying all the time...transmission similar to what you are seeing, between 91 & 94.

I did note that with higher revs the oil temp would rise, but by dropping a gear ratio to lower revs it would begin to fall again. Usually that would indicate a water pump if it were coolant, but this is oil temp so at a bit of a loss.

As I initially wrote I pulled the lower bull bar skirt off to get some air flow, it might have made a bit of difference to the coolant temp but not the oil temp of course.

The coolant temp gauge in the dash runs up to the higher mark just above centre when up around 110c. not to the upper quarter though where the red starts...

I have this one booked in for a radiator & block flush early next week, and will have the thermostat replaced as well. It should be a 94 degree I think. The temps are all over the place so am thinking the thermostat may not always be fully opening.

I'll see whether this flush helps at all, I am heading down to Fingal with the van in a couple of weeks which will see 100kmh again on the highway but no hills...

[drover]

If your towing over 95kph temps will increase, could be corrupted air flow from bugs and crap, mates when he lifted the manifold for the bastard hose found the valley full of grass seeds, checking his coolers found they were full as well, so a good check might be needed......... Coolant temp will affect oil temp to a degree so I would be onto the coolant system myself .............. You dumped all the fluids and filters earlier didn't you ?

Have no idea what temp my thermostat is but if it needs replacing since I tow a lot I will be using one that starts to open around the 86 deg mark, far better for towing..... If it starts to open mid 90's then engine is going to run warmer, something I don't want at all........................

[Jeeper6]

I had given the radiator area a good hosing best i could with reasonable pressure, and had checked for debris between radiator cores but see nothing obvious...I'll have a good look again as that had crossed my mind.
It would be far better to separate all the cores of course.

I changed engine oil and filter the day after picking it up...coolant to be done next week with a total block and radiator flush.

The oil does meet coolant in that tiny oil cooler on the side of the block for a brief time, but not enough I reckon to cool it very much at all....especially if the coolant is over hot already!

I will have a look today at what thermostats are available for these, I thought I had read somewhere that the standard thermostats were 94 degrees, that seemed to be supported by my last Jeep running pretty constantly at 94 degrees.

As you note, an overly hot engine is not desirable at all!

[drover]

Never blow water or air at cooler only across the fins, you only blow the crud further in which is not what you want....... probably find the coolant change might help things a lot, might even pay to change the oil filter and oil earlier than normal to flush things out as well..... Thinking along temp lines it wasn't overlly hot either when you went on that run so could be coolant flow or dodgy thermo ..... when I have thermo dramas I would start by pulling the wax plug out, allows flow all the time with restriction, many just remove the thermo all together which just allows full flow and engine doesn't get hot enough, just removing the wax plug lets it get near operating temp, unsure if it can be done with these dumb thermostats though.... this style seems to be the thing now, for some reason possibly all to do with a $$$.