Our car is 8 years old it's been on all the time no problem. Maybe it's been designed to work that way! It does mean when we lived in a city we at least didn't pollute stopped at the traffic lights
Do you do a warm up & warm down of your moho engine ?
- Thread starter mohobot
- Start date
Drove home from north Wales and the engine defo got warmed up. Now cooling down so all good
A new vehicle should always be "run in" as this is stated by the manufacturer.
The reason being, not just the tightness of the engine components, but the whole vehicle itself.
All the components such as wheel bearings, UJ's, etc, etc, are brand new and tight.
So running a brand new vehicle for long periods of time makes all the new components get very hot,
whilst still very tight......hense, run in at a steady but not excessive speed.
Running in will make your vehicle last for many more years to come, believe me!
Some people think that because an engine has been "bench tested" that it is run in............utter crap!
It has only been run on a bench to check that the engine runs as it should. It is definitely not run in.
When I say "vehicles", I don't mean aeroplanes, 'cos you can't really run them in at a lower speed really!
So, taking your hypothesis about everything tight and overheating when new, what happens with aircraft engines?A new vehicle should always be "run in" as this is stated by the manufacturer.
The reason being, not just the tightness of the engine components, but the whole vehicle itself.
All the components such as wheel bearings, UJ's, etc, etc, are brand new and tight.
So running a brand new vehicle for long periods of time makes all the new components get very hot,
whilst still very tight......hense, run in at a steady but not excessive speed.
Running in will make your vehicle last for many more years to come, believe me!
Some people think that because an engine has been "bench tested" that it is run in............utter crap!
It has only been run on a bench to check that the engine runs as it should. It is definitely not run in.
When I say "vehicles", I don't mean aeroplanes, 'cos you can't really run them in at a lower speed really!
In actual fact the thing that's the worst thing to do with a rebuilt aeroplane engine is treat it too gently it needs variations in power and has a different oil for the running in period. The explanation I heard was that the machining wasn't to a final polish and running in at a slow steady speed can lead to glazing of the bores requiring another rebuild. Slow and steady isn't necessarily the kindest!A new vehicle should always be "run in" as this is stated by the manufacturer.
The reason being, not just the tightness of the engine components, but the whole vehicle itself.
All the components such as wheel bearings, UJ's, etc, etc, are brand new and tight.
So running a brand new vehicle for long periods of time makes all the new components get very hot,
whilst still very tight......hense, run in at a steady but not excessive speed.
Running in will make your vehicle last for many more years to come, believe me!
Some people think that because an engine has been "bench tested" that it is run in............utter crap!
It has only been run on a bench to check that the engine runs as it should. It is definitely not run in.
When I say "vehicles", I don't mean aeroplanes, 'cos you can't really run them in at a lower speed really!
From aviation safety magazine
"The trick is to force the rings against the cylinder walls during the break-in process, minimizing lubrication. This is best accomplished by running the engine at high power settings, which generate the highest internal cylinder pressures, maximizing both ring expansion against the cylinder walls and friction"
Just the opposite of what people would expect. If modern engines are designed to be used out of the box with a full range of power settings being too gentle could be bad!
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stuartholmes
LIFE MEMBER
And all these years I've been thinking it was just me who did that with the fuel pipe...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.
Erm
don’t know what to say…. No malfunction… I’m not suggesting jeopardy, so for example not the engine overheating and too hot, but outside of parameters for the engine to go off via stop:start too hot! 
My later M5’s both had stop start, but it didn’t operate all the time for the reasons mentioned above. This could be the charge/inlet temperature too high, coolant or oil temp too high, turbos too warm etc etc
Ahh.... should have got AMGs from the competitor.....Erm
My later M5’s both had stop start, but it didn’t operate all the time for the reasons mentioned above. This could be the charge/inlet temperature too high, coolant or oil temp too high, turbos too warm etc etc
Yes you can, spent many hours running piston engines, then changing the oil. Boring just sitting there. Engineers rarely run piston engined helicopters so the junior pilot gets the job. One of the lads once crawled past the cockpit with a drawing of a cloud on a stick to keep him awake.A new vehicle should always be "run in" as this is stated by the manufacturer.
The reason being, not just the tightness of the engine components, but the whole vehicle itself.
All the components such as wheel bearings, UJ's, etc, etc, are brand new and tight.
So running a brand new vehicle for long periods of time makes all the new components get very hot,
whilst still very tight......hense, run in at a steady but not excessive speed.
Running in will make your vehicle last for many more years to come, believe me!
Some people think that because an engine has been "bench tested" that it is run in............utter crap!
It has only been run on a bench to check that the engine runs as it should. It is definitely not run in.
When I say "vehicles", I don't mean aeroplanes, 'cos you can't really run them in at a lower speed really!
PP Bear
LIFE MEMBER
All turbos require a supply of fresh oil to bathe in and letting them idle on startup will allow fresh oil to circulate around the turbos bearings, before we put it under load. A diesel engine may well be cruising at 2-3000 rpm (as an example) while the turbo may well be doing 200,000rpm. It needs lots of oil.
Therefore running it down is essential, so that when the engine stops and the red hot turbo isn’t spinning in a pool of oil that’s also red hot, at this amazing rpm, but not getting the fresh oil around it. This way the oil can quickly fail at the very place that you need it to work. Allowing the engine to idle, will allow the turbo to slow down, spinning in a continuous supply of oil, that’s helping to cool and lubricate it.
Some manufacturers have a hydraulic spring plunger system fitted, that compresses under normal oil pressure and then when Joe Public flys down the motorway, pulls up in the service station or home and immediately switches off the engine, the spring will slowly reassure itself and deliver a supply of oil to the turbo bearing to assist in getting it cool and lubricated. Probably stop start systems springs to mind.
Laugh or disbelieve, it’s your turbo so to speak and the theory of not letting diesel engines idle certainly doesn’t stand up in my training circles. I let mine idle endlessly if needs be, always have
Modern turbos are an engineering marvel these days, especially when fitted with a variable vein system.
Variable vein In operation.
Coked up and failed for whatever reason.
Therefore running it down is essential, so that when the engine stops and the red hot turbo isn’t spinning in a pool of oil that’s also red hot, at this amazing rpm, but not getting the fresh oil around it. This way the oil can quickly fail at the very place that you need it to work. Allowing the engine to idle, will allow the turbo to slow down, spinning in a continuous supply of oil, that’s helping to cool and lubricate it.
Some manufacturers have a hydraulic spring plunger system fitted, that compresses under normal oil pressure and then when Joe Public flys down the motorway, pulls up in the service station or home and immediately switches off the engine, the spring will slowly reassure itself and deliver a supply of oil to the turbo bearing to assist in getting it cool and lubricated. Probably stop start systems springs to mind.
Laugh or disbelieve, it’s your turbo so to speak and the theory of not letting diesel engines idle certainly doesn’t stand up in my training circles. I let mine idle endlessly if needs be, always have
Modern turbos are an engineering marvel these days, especially when fitted with a variable vein system.
Variable vein In operation.
Coked up and failed for whatever reason.
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Last edited:
funflair
LIFE MEMBER
My brother bought a Jap import Impreza with a "turbo timer" you switched off locked the car and walked away and it switched off when it had cooled down, worked well till he rolled it, 5 times I think he countedI had Ford Cosworths in the 90's and after a motorway run, then slow drive 3 miles to home I used to let the engine idle for a minute or two to cool to allow the Garret Turbo to cool down whilst still circulating oil. It could often be seen to be glowing Red Hot under the bonnet, but the cooling fan would kick in and sometimes run for 5/10 minutes after walking away before the Turbo was deemed cool enough by the thermostat. It was mentioned in the Car Owner Manual to always let the engine idle to cool the turbo after a run, so I always tried to do this....if I had the time.
The Van however is a modern diesel with lower engine revs and a smaller Turbo so I don't have to think about letting it idle and cool down so much, if the fan kicks in after stopping then its probably half way through doing a Regen to clear The DPF which doesn't happen that often when shutting the engine down thus far.
Good point on mentioning the Stop/Start on modern vans, that somehow contradicts the idea of letting the engine idle for an extended time before shut down, then again maybe it knows when to allow the stop/start function, I know our car does.
LES
then just got out and surveyed the scene of total carnage and telephoned me as I was not far behind him after leaving work, basically "don't worry I have had an accident" I said something along the lines of do you need a tow out, but he said it was past that and anyway it was in the middle of the road, and the side, and the field and most other places with 100 metres.
- Aug 17, 2021
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Most engines are not run on the test bench but rather the first time they start is when they roll off the production line.A new vehicle should always be "run in" as this is stated by the manufacturer.
The reason being, not just the tightness of the engine components, but the whole vehicle itself.
All the components such as wheel bearings, UJ's, etc, etc, are brand new and tight.
So running a brand new vehicle for long periods of time makes all the new components get very hot,
whilst still very tight......hense, run in at a steady but not excessive speed.
Running in will make your vehicle last for many more years to come, believe me!
Some people think that because an engine has been "bench tested" that it is run in............utter crap!
It has only been run on a bench to check that the engine runs as it should. It is definitely not run in.
When I say "vehicles", I don't mean aeroplanes, 'cos you can't really run them in at a lower speed really!
That’s not strictly true they are ran but they are driven by a motor rather than by the introduction of fuel. This is to ensure that they can stand the forces of high speed rotation.
On run in, I don’t personally think it’s necessary with modern lubricants but a variable load is much more preferable than a sustained load.
Drivelines don’t really need to run in although they do loosen up over the first 30 - 40k.
- Aug 17, 2021
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Thing is we’re talking about a medium duty diesel engine in a van and not a big heavy industrial engine in a piece of equipment that holds and struggles to dissipate heat or a truck engine working at the verge of its duty cycle for long periods.All turbos require a supply of fresh oil to bathe in and letting them idle on startup will allow fresh oil to circulate around the turbos bearings, before we put it under load. A diesel engine may well be cruising at 2-3000 rpm (as an example) while the turbo may well be doing 200,000rpm. It needs lots of oil.
Therefore running it down is essential, so that when the engine stops and the red hot turbo isn’t spinning in a pool of oil that’s also red hot, at this amazing rpm, but not getting the fresh oil around it. This way the oil can quickly fail at the very place that you need it to work. Allowing the engine to idle, will allow the turbo to slow down, spinning in a continuous supply of oil, that’s helping to cool and lubricate it.
Some manufacturers have a hydraulic spring plunger system fitted, that compresses under normal oil pressure and then when Joe Public flys down the motorway, pulls up in the service station or home and immediately switches off the engine, the spring will slowly reassure itself and deliver a supply of oil to the turbo bearing to assist in getting it cool and lubricated. Probably stop start systems springs to mind.
Laugh or disbelieve, it’s your turbo so to speak and the theory of not letting diesel engines idle certainly doesn’t stand up in my training circles. I let mine idle endlessly if needs be, always have
Modern turbos are an engineering marvel these days, especially when fitted with a various vein system.
Variable vein In operation.
View attachment 953273
Coked up and failed for whatever reason.
View attachment 953275
Each to their own and all that and if people sleep better in their beds for a bit of cool down then fair play but it’s not standard practice in road transport and neither has it been for the last 20+ years.
As already said you won’t ever put a mh engine under the loads that the average Amazon/DHL/any parcel company you can think of driver will on a daily basis.
OP
OP
- Feb 21, 2024
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I believe big end bearings suffered premature wear/failure on some early stop start vehicles, I expect the bearings were not lubricated & tough enough for so many stop starts over previous designs?
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My Freelander turbo diesel is close to 250k miles on the original turbo. Never bothered to run it to cool down the turbo because it's not really working very hard. The tiny Smart car petrol turbo always gets a cool down for a minute or two if coming off a blast since it's putting out a whopping 
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It made me laugh where did people think the valve was to control the fuel!
Stop / start has been around for about 40 years now, so I don't think this one will affect Euro 6 vehicles.
- Dec 24, 2014
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I think raising the hose to get the last drops out is a hangover from back in the day. I can remember when in the late 1950's my Dad used to operate the private pump to fill up the firm's vans at his wholesale grocery business in Brighton. First he cranked a handle that pumped petrol up to a glass container like a wine maker's demijohn above head height which held exactly one gallon. Next he put the delivery nozzle into the van's tank inlet and operated the delivery nozzle's trigger to release the petrol which fell by gravity. Because the long delivery hose ran down to ground level before rising to the nozzle it was necessary to raise the hose in order to drain the hose and empty the demijohn of the whole gallon.
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- Oct 27, 2022
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I still do it
stuartholmes
LIFE MEMBER
Upstr
Upstream of the trigger & spout
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Fun fact. My performance car actually has an oil warmer. Coolant water has a heat exchanger with the oil. Water is pretty much always hotter than the oil...
Oil coolers (air/oil) exist of course but not on any normal production engine AFAIK.
If I nail the transit and stop, the engine doesn't necessarily imediately stop automatically. However, if it does, it does have an electric cooling system pump that runs on. AFAIK the turbo is water cooled.
As someone above said, turbo is at over 100,000 rpm and if you shut off oil and cooling before its calmed down it's bad, very bad.
Stop start is so manufacturers meet green targets…they do not concern themselves as to how good it is ( or not) for the life of the engine.
I always switch off stop/start function in my Moho and in my cars.
It’s just a repeated mechanical activity that is simply not required.
stuartholmes
LIFE MEMBER
Unless you live or work in an area where the air is polluted by vehicles idling at traffic lights...
And starting the engine continuously produces more pollutants than tickover
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Is that true or a myth with diesels? With petrol I can see a small amount of unburnt fuel escaping eveytime you start but not with diesel also if you start the engine yourself a lot tend to rev it but it doesn't do that on stop start. Those things together with the fact that stop start reduces fuel consumption and is needed to meet emissions targets suggests to me that thinking there's more pollution using stop start is an urban mythAnd starting the engine continuously produces more pollutants than tickover
From the RAC common stop start myths busted
www.rac.co.uk
Stop-start engines and engine idling – the law and common myths revealed | RAC Drive
Does it use more fuel? Does it cause more pollution? We decided to unearth the facts and find conclusive answers.
- Feb 14, 2021
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My 300bhp VX220 got too hot being thrashed around a track in the south of France at the height of the summer. No malfunction just extreme use.
Sorry, mythinformation.And starting the engine continuously produces more pollutants than tickover
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