Fast tickover for aircon

[Jofang]

We've just bought a 2016 Hymer 6 wheeler with the Fiat 3 litre motor, only done 24,000 miles. I have been considering having an aircon fitted on the roof but the price is staggering. We live in France and we only wild camp or use an aire and we seldom use campsites, so the aircon would have to work from the leisure batteries not the mains and I've been quoted in excess of £8,000 for a working system that includes the roof aircon, 2500W inverter, twin Lithium batteries to replace the existing gel ones and installation of the lot. I'm sure the dealer can justify the price but it's just too much. My wife is in favour of running the 3 litre engine for half an hour with the cab aircon operating, as the cab aircon is very efficient, but I'm not sure this is healthy for a modern diesel to run at a slightly faster than idle for twenty minutes or so whenever we need to cool down inside. I've read comments previously that say long idling with modern diesels is not good, but is this true for the older generation engines or only the more recent models fitted with all manner of environmental devices. I know that much simpler diesels can be run for hours on end at the same speed, such as my tractor, but I don't want to push my luck and risk causing engine problems. Any advice welcome.

 

[Odd-no-more]

What about an air-con unit and a generator?

 

[gpat]

You won't make many friends having the engine running?

I'm no expert on engines but I have always been told that vehicle engines make lousy generators and that it does them no good at all.

 

[Otter Spotter]

I think the long tick over is not good for vehicles with a DPF which may clog up and you could have to do a forced regeneration, but I am sure someone more knowledgeable than me will be along soon.

 

[Pausim]

Light loads (tick over) is not good for the cylinder bores either, can cause glazing.

http://coxeng.co.uk/engine/bore-glazing-and-polishing-in-diesel-engines/

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[TerryL]

Thinking a little outside the box - are you SURE you need full air-conditioning? We had a unit on our Bolero but it was never used as we don't do campsites much. I replaced it with a Maxxair unit, operates on 12v and doesn't cane the batteries, Okay it doesn't cool the air but we find circulation is enough. Ours gets used almost every trip, unlike the full aircon unit.
There's a couple of threads running about these units.

 

[Basildog]

Air conditioning isn’t really practical without ehu or possibly a fairly large generator
Running your engine for prolonged periods at low revs is almost certainly a recipe for problems with these modern sewing machine diesels

 

[Lenny HB]

My wife is in favour of running the 3 litre engine for half an hour with the cab aircon operating, as the cab aircon is very efficient, but I'm not sure this is healthy for a modern diesel to run at a slightly faster than idle for twenty minutes or so whenever we need to cool down inside. I've read comments previously that say long idling with modern diesels is not good, but is this true for the older generation engines or only the more recent models fitted with all manner of environmental devices.

The 3 Lt is a modern diesel engine and doing that is one of the best ways of wrecking it. If you are going to run it stationary you need to take it for at least a 10 mile drive to get it fully up to operating temperature first, even then you still stand a chance of clogging the CAT & DPF.