Do you do a warm up & warm down of your moho engine ?

[mohobot]

Recieved wisdom says you should warm up a diesel vehicle on idle for at least 45 seconds before driving off, personally I try to do longer, especially if I have to drive up a hill etc & also if its cold. The same wisdom says you should do at least similar after driving, preferably a bit longer if for example you have been on the motorway & pulled into a service station car park, & the turbo has been fully engaged for a long period.
I dont see many people doing the above with their vehicles, which is one reason I have tried not to buy second hand vehicles!! What do you do & why ?

 

[2bob]

i do all that

 

[Lenny HB]

Probably going to be running for at least 45 sec while you get your seat belt on, adjust seat and turn on satnav.
What you shouldn't do is let a diesel run for any length of time before driving off.

After a run on a motorway or fast road at a constant high speed I always let it idle for at least minute before turning off.

 

[PaddyM]

Whose recieved wisdom ? Where’s the evidence based research ?
This so far is purely anecdotal.
I’m open to facts ,
Interesting discussion tho

 

[pappajohn]

A diesel should be driven as soon as it's started, it will warm up quicker under load.
Idling for a few seconds after a fast run will do no good whatsoever.....it will still be too hot to touch 10 minutes after stopping.
Next it will be said you have to run in a new van at a reduced speed .....utter crap.

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[meanders]

Ensuring the oil is circulating properly before applying many revs makes sense, but other than that , all the advice these days with modern engines is that you start it and move away with a gentle driving style to allow the engine to warm naturally. I was told probably 30 years ago , by an engineerat Williams racing near Oxford that trying to 'cool' an engine by leaving it on tickover after a run is a complete waste of time and fuel. Even on tickover the engine is still creating a huge amount of heat. that the fan will be trying to disperse. Clearly if running the engine at maximum rev's in a low gear on a motorway isn't likely to do it much good, but if you are in the correct gear the engine is likely to be running at under 3000rpm anyway. Blocks these days are much better designed for thermal efficiency than they were half a century ago. .

 

[dash300]

The oil will circulate sufficiently within a few seconds on start up, I wouldn't worry. I remember people used to rev the engine before switching off years ago so there was fuel in the system for the next start up!!!!!
Those were the days when you would see people at fuel stations lifting the filling pipe to get the last drop out!
Modern engines, state of the art lubrication things have moved on.

 

[meanders]

After a run on a motorway or fast road at a constant high speed I always let it idle for at least minute before turning off.

But surely the issue is engine speed, not vehicle speed? Even at 70, engine speed should be no more than 3000 rpm. Running round town in third will probably be about 2500rpm. Do you do the same having driven through town for an hour stopping and starting? The engine will be just as hot!

 

[mohobot]

Whose recieved wisdom ? Where’s the evidence based research ?
This so far is purely anecdotal.
I’m open to facts ,
Interesting discussion tho

The thermal imaging camera view ?

 

[meanders]

The oil will circulate sufficiently within a few seconds on start up, I wouldn't worry. I remember people used to rev the engine before switching off years ago so there was fuel in the system for the next start up!!!!!
Those were the days when you would see people at fuel stations lifting the filling pipe to get the last drop out!
Modern engines, state of the art lubrication things have moved on.

Yes I am aware of that, I was simply reinforcing the theory of not over-reving a stone cold engine.

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[Outdoors Dad]

Yeah I let mi e idle for a minute or two if it's stood a while, to let the oil glug about.

 

[meanders]

Yeah I let mi e idle for a minute or two if it's stood a while, to let the oil glug about.

15 seconds is more than adequate unless you have a problem with the oil pressure pump.

 

[mohobot]

A diesel should be driven as soon as it's started, it will warm up quicker under load.
Idling for a few seconds after a fast run will do no good whatsoever.....it will still be too hot to touch 10 minutes after stopping.
Next it will be said you have to run in a new van at a reduced speed .....utter crap.

Run in is something I do, I just cant help it. The next question may be do you change the oil after "run in" well it seems the answer is yes & I am glad I do. Who wants metal particles in the oil system for 2 years? In fact my moho when new was over a year in storage & conversion, changing the oil at 2 years would in fact be 3+ years total!

 

[Richard n Ann]

I'd have thought the engine will get even hotter on tick over after a run, while driving the radiator and whole engine is being cooled by a fast air flow. On tick over all the air is still and after a short time the cooling fan has to come on.

My motorcycle has a water temperature display and you can see it happening, in traffic the water temperature will climb to 103°c and the fan comes on (switches off about 95)

 

[Daffy64]

I wouldn’t bother too much re warm up as long as you take it steady I.e. normal driving.

As to letting the turbo wind down, as long as your not going from full load to stopped immediately then you’ll be fine, think about a run up a big hill at high speed and you roll into a lay bye at the top, the process of finding a place to stop will a slow everything down.

However you drive your van it will never be as hard as the Amazon man…

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[mohobot]

I'd have thought the engine will get even hotter on tick over after a run, while driving the radiator and whole engine is being cooled by a fast air flow. On tick over all the air is still and after a short time the cooling fan has to come on.

My motorcycle has a water temperature display and you can see it happening, in traffic the water temperature will climb to 103°c and the fan comes on (switches off about 95)

It seems the turbo is the importsnt item here

 

[Shrimp]

I worked in a stable years ago-as a teenager-we had an old horse box lorry and that was started up and left to run for a while. Not something to do now with modern engines.
It was an old TK and this was in the winter weather, frosty, and cold with the old dung heap steaming gently, fantastic days!

 

[Richard n Ann]

It seems the turbo is the importsnt item here

You'll have to explain, I'm not watching videos as I'm down to 1.5GB and it's got to last me until the 24th I'm even using Opera Mini browser

 

[dash300]

Yes I am aware of that, I was simply reinforcing the theory of not over-reving a stone cold engine.

Was a general comment not a dig!

 

[dash300]

You'll have to explain, I'm not watching videos as I'm down to 1.5GB and it's got to last me until the 24th I'm even using Opera Mini browser

Turbos will spin for a short time after the engine shuts down and for that period will not have oil supply to bearings.
That's only going to be an issue if you switch off when the Turbo is running at full tilt which is very unlikely I would say!

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[DavidG58]

We also read ours a story before we go to bed, it seems to like it

 

[Kannon Fodda]

Only a racing car can potentially start and be thrashed off the line or alternatively screams to a stop in the pits.

For mere mortals we start the engine and extract ourselves from drives, car parks, campsite pitches, or whatever when flooring it is simply not going to happen. The most effort would be getting out of a junction or at traffic lights, all of which means your engine must have been turning over for at least a short while. For stopping and shutting down the worst might perhaps be a stop start type engine where you come to a temporary halt at a slip road traffic light controlled junction. But I've yet to be able to do a fast drive braking hard to stop and shut off engine when arriving into a final park up. So there will always have been a less stressed period for any reduced turbo and other load.

 

[Carpmart]

Some of these replies really do make me chuckle; there is a distinct lack of basic mechanical knowledge.

 

[Northernraider]

I thought I'd been transported back to 1960 there for a second

The danger of youtube videos.

 

[meanders]

Some of these replies really do make me chuckle; there is a distinct lack of basic mechanical knowledge.

Go on please?

I appear to have missed something.

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[Barclaybasher]

I thought I'd been transported back to 1960 there for a second

The danger of youtube videos.

Anyone de-coked a petrol engine or ground in the valves lately?

 

[carolyn]

A diesel should be driven as soon as it's started, it will warm up quicker under load.
Idling for a few seconds after a fast run will do no good whatsoever.....it will still be too hot to touch 10 minutes after stopping.
Next it will be said you have to run in a new van at a reduced speed .....utter crap.

That’s a relief. Other than driving our brand new van home from Leeds to Sherborne in Dorset the only trip we made was the 40 miles to Vanbitz plus the 40 miles back before heading off on our 2 month tour to Romania and Bulgaria! Obviously not ideal but daughter’s wedding came first so we assumed this running in business dated back to the dark ages.

Rather like this 9 speed Auto. Handled the Transfagarasan pass beautifully. We saw bears.

 

[funflair]

Turbos will spin for a short time after the engine shuts down and for that period will not have oil supply to bearings.
That's only going to be an issue if you switch off when the Turbo is running at full tilt which is very unlikely I would say!

I thought it was more to do with the temperature of the turbo and what it does to any oil that is just sat there rather than circulating, and to answer the original question, Yes if I had been flogging up a hill at full boost I would not shut straight off at the top preferring a bit of level driving off boost and then switch off, I believe our turbo has it's own water cooling system anyway that will run on after the engine is stopped.

 

[WESTY66]

If we shut any of the big yellow plant (Volvos) at work off within at least 2 minutes of working a fault will come up “Hot turbo shut down” Caterpillars will run on regardless of turning off and removing the key till they’ve reached a cooler temperature with the turbo!
Old cats used to have a BIG sticker on dash “LET ENGINE IDLE FOR 5 MINS BEFORE SHUTTING OFF”

Interpret that as you will!
Me? I will always idle for a while before shutting off, after 40 years of driving big earthmovers it’s instilled in me

 

[VXman]

It seems to me most motorhomes sit for at least 5 minutes withe engine running before moving off!!. Particularly annoyingly if they are parked up next to you. Goodness knows why they can't set the sat nav, put seat belt on, pick their nose etc before starting the engine. And why start it before the wife has even finished doing the washing up?

As for after - I will allow my high performance turbo charged sports car engine to idle a little after a high speed run just to allow the turbo to cool a little but a bit unnecessary in a motorhome.

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