motorhome storage engine question

[Hymer Mike]

Hi all,

new to this motorhome life, so I have a question all ready. I shan't be using my MH for about 3 months, so it's in storage for now, my question is, how often should I start it up, how long should I leave it running for, should I roll forwards and backwards to help the tyres? any other suggestions from the forum would be most welcome. PS: Have drained the water down and turned off the gas & opened the fridge. :-S

[aandncaravan]

It depends on why you are running the engine?

 

If it is to just circulate the Oil to reduce the risk of internal corrosion then it only needs to be for a minute or two. That will solve that problem, but may introduce other issues?

 

Running the engine for just a few minutes can leave a fair amount of water vapour inside the engine and exhaust system. This can then accelerate corrosion in both.

Therefore it is best to get the engine hot by warming it up at a fast idle (about 1100rpm).

 

 

If you are running the engine to put charge back into the battery, as many try to do, you should be aware that running the engine for an hour will only put about 15Ah into a 100Ah Starter battery, so a long time to put in little.

 

Running the engine for 15 minutes, which seems like a really long time when you are sitting there with your foot holding down the accelerator very slightly, will put about 5Ah into the battery. Obviously if you do this once a month for 3 months you will most likely have sulphated, flat batteries at the end of that time.

 

Ideally take it for a 60 minute run as this will help stop the brakes seizing, tyre flat spotting, etc as well, but it sounds like this might be impractical in your case?

If so, we would suggest you remove the batteries so you can put them on 4 weekly charging in the Garage and leave the engine alone.

Don't start the engine until you can warm it up gently then give it a good run of about 40minutes. Just running the engine for 15 minutes will do more harm than good.

 

Around 30 years ago it did not harm a Diesel engine to let it idle for minutes at a time to warm it up and put a couple of Ah into a battery. Not uncommon to see this practise on sites/stops.

However doing this on a modern Euro4/5 engine will most likely result in Soot/Carbon build up on the sensors, as these engines rely on high temperatures to keep them clean.

Just idling a Euro 4/5 engine will not usually generate enough heat to do this. Often causing Dash warning lights to become lit up over time.

 

It is important with a modern Diesel to get it hot when you use it and, at least occasionally, make it work hard to get combustion temperatures up.

Letting a modern Diesel idle for just a few minutes can contribute to issues further down the line.

 

Especially important not to idle the later Ford transit engine as this is already very finicky about Injection Spray patterns. Carbon build-up on Electronic Injectors can alter these.

 

The old pressure actuated Injectors operated so fiercely they cleaned themselves of any carbon residue, so not a problem in the past.