Mitsubishi Shogun 3.2 Diesel LWB Auto. 2002 - Marginal Cooling Problem

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Mon 19 Sep 2011 21:55
Mitsubishi Shogun 3.2 Diesel LWB Auto. 2002 - Marginal Cooling Problem - Johnxair

When towing a horse trailer (empty weight approx 1000Kg) the temperature gauge fluctuates rather a lot, depending on gradient of the road. For example: yesterday on M5 between Bristol & Tewkesbury where there are no steep climbs, the needle got more than half-way between normal and the red sector when climbing, but comes back to normal during descents. There is one hill locally (approx 1 in 8) where I always have to pull in & let it idle for 5 mins before continuing. I am gentle with the right foot, yesterday on M5 I was doing around 50 to 55 mph.

This issue only occurs when towing an empty or lightly loaded horsebox. No more than 1500Kg. The towing limit for the vehicle is 3300Kg & I've not tried loads of this weight for sufficient distance to show a problem.

Running solo, the temperature never varies whatever the speed or road conditions, even if run for 5 hours continuously.

Can anyone tell me whether this should be expected. If not, where should I begin looking for a cause.

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Tue 20 Sep 2011 08:58
Mitsubishi Shogun 3.2 Diesel LWB Auto. 2002 - Marginal Cooling Problem - TeeCee

You don't mention that you are losing coolant, so presumably you are not. Therefore:

Sounds to me as though the cooling system is working as it should, but under heavy load when moving at lower speeds (as in when towing uphill) there just isn't enough draught through the rad to keep on top of the heat generated.

It may just be that the standard fan isn't quite up to the job or is past its best and swapping it for a decent Kenlowe product may well sort your problems out.

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Tue 20 Sep 2011 09:21
Mitsubishi Shogun 3.2 Diesel LWB Auto. 2002 - Marginal Cooling Problem - Falkirk Bairn

Partial blockage?

Flush the radiator and see if that helps -

Cheaper and easier than buying / installing a fan

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Tue 20 Sep 2011 13:06
Mitsubishi Shogun 3.2 Diesel LWB Auto. 2002 - Marginal Cooling Problem - gordonbennet

Whilst looking at partial blockage and a good opportunity to renew the coolant?, shine a light behind the radiator and look through all the fins, it's possible the radiator needs a good hosing out from behind of all the flies and muck it's accumulated over the years.

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Tue 20 Sep 2011 19:24
Mitsubishi Shogun 3.2 Diesel LWB Auto. 2002 - Marginal Cooling Problem - Johnxair

Many thanks for these suggestions. I confirm there's no coolant loss. It just gets blown into the overflow tank when she gets hot but goes back to the rad afterwards.

I think hosing out the fins & flushing the rad core might be a good start. I would prefer to remove the rad & backflush it, but with oil connections to the rad as well as water, it's not quite so simple. It will have to be done in situ.

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