Overheating problem with 2014 Grand Cherokee Diesel

[Wombat6]

We are currently traveling around northern Australia towing a large caravan (approx 2.8 ton) with a 2014 Grand Cherokee Limited - diesel. Since getting into northern NT and with the higher temperatures (>38C) we have been plagued with overheating problems. What we find is that once the temperature gets above around 116C the temperature then rapidly increases and the overheating alarm goes off. We then find steam and radiator fluid coming out of the coolant overflow outlet.

We took it to the Jeep place in Darwin who had it for 2.5 days. Because they couldn’t replicate the problem (we only find it when towing) they decided that it was just due to an air blockage which they thought they had fixed. However, since leaving Darwin to try and continue our trip we have found the problem consistently re-occurring. If we drive between 80-90 km/hr and make sure the temperature does not go above 114C then we can manage the problem. However, as just happened, we relaxed and didn’t notice the temperature increase to 120C and the alarm went off. I then discovered steam and some coolant leaking out.

The problem I believe is that when the temperature and thus pressure builds up in the system the overflow bottle is failing to contain this. I have tried replacing the radiator cap to no avail. Does anyone have an experience with this or thoughts?

[Classic Boy]

Have you towed a similar weight previously under similar conditions and not experienced overheating or is the first time?
I am asking because it helps in determining whether a fault maybe developing with the cooling system or it could be a cooling system performing normally that just cannot keep up with the engines heat output under the heavy towing loads.

The temp suddenly shoots up at 116c probably because the coolant starts to boil and a gas (steam) cannot carry the same amount of heat as the liquid coolant.

It is interesting that the coolant is boiling at 116c as good quality coolant at a 50/50 mixture is usually good to 133c before boiling.

Has the vehicle been using coolant previously and has it been topped up with 50/50 coolant mix or water?

Other owners of similar equiped GC's of the same vintage and towing similar loads in the the elevated heat will probably will share their experiences.

[timsarg]

i would be putting in a bigger radiator if you are towing a nearly 3 tonne van in 38 degree heat . When i get round to purchasing a van the first thing i will be doing is putting in a bigger radiator

[Barboots]

A true 45 degrees plus, a full-height 2.5T van, 275/65R18, mild headwind and the posted limit for several hours didn't phase our MY14.

Has your coolant been added to? The required coolant is hard to find, and not compatible with off-the-shelf products.

Cheers, Steve

[Clarky]

What modifications do you have? Bullbar? Driving Lights? Winch?

[desertman]

Wombat6,

I have just endured 6 months of similar problems down here in Melbourne.

Jeep could never find any fault and tried to tell me it was normal.

Eventually, I managed to convince them that it was not and they pulled down the engine only to find that one of the heads had a minor warp.

Three months later they managed to replace both heads and my overheating problems appear to be over.

BTW, my overheating only ever occurred when towing a 1.5 ton van - never without. The saga started late last year when a coolant hose came undone and the vehicle lost all it's coolant. It overheated numerous times after that and got progressively worse.

Your symptoms sound the same. Coolant system over pressurises and pumps coolant out of the overflow on the expansion bottle.

Hope this helps.

Cheers,

DM

[Starion VR4]

Originally Posted by desertman

Wombat6,

I have just endured 6 months of similar problems down here in Melbourne.

Jeep could never find any fault and tried to tell me it was normal.

Eventually, I managed to convince them that it was not and they pulled down the engine only to find that one of the heads had a minor warp.

Three months later they managed to replace both heads and my overheating problems appear to be over.

BTW, my overheating only ever occurred when towing a 1.5 ton van - never without. The saga started late last year when a coolant hose came undone and the vehicle lost all it's coolant. It overheated numerous times after that and got progressively worse.

Your symptoms sound the same. Coolant system over pressurises and pumps coolant out of the overflow on the expansion bottle.

Hope this helps.

Cheers,

DM

Yep sound like this is your problem, or a leaking head gasket.