The "correct" way to start a diesel engine. (1 Viewer)

[GeriatricWanderer]

I've run numerus vehicles in my lifetime, some petrol engined and some diesel. Some straight off the production line and some middle aged.

From somewhere in that time I've picked up the understanding that the correct way to start a diesel engine is:
Right foot off the gas pedal.
Left foot hard down on the clutch pedal.

I've never really understood the technical logic of the clutch pedal process but assumed it was something to do with taking some pressure off the flywheel while the engine is turning on the starter.

I've recently bought another car, 10 year old diesel engined, and was browsing the User Manual expecting to see some precise instructions re starting and there is but only to keep that right foot off the gas pedal - but no mention at all of the clutch pedal depression process.

Somewhere amongst this vast membership must be someone who knows, or think they know , the "correct" process.

As always, your contributions will no doubt be varied - and welcomed.

And before you are tempted - yes, I know, some of you drive automatics

 

[BreweryDave]

I find that turning the ignition key often works .............

 

[mike mcglynn]

My car is a diesel and will not start unless clutch is depressed, 2013 model

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[wizzer59]

Never heard of it, all my cars and vans have been Diesel and all started without depressing the clutch

 

[MillieMoocher]

Had one car which needed the clutch pedal depressing to start.

But in a manual I always start the car with clutch pedal down, having driven a lot of multi user cars where last person has left it in gear...certainly wakes you up as you lurch forward

 

[Derbyshire wanderer]

I think the clutch pedal down was more to do with preventing accidental movement if left in gear rather than being a major help to the starter motor.
The important bit when starting a Diesel engine is to give the glow plugs (when fitted) time to heat up before engaging the starter motor.

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[jollyrodger]

TD I was tought foot off throttle ,clutch down to ease pressure on f/wheel & no drive .let it tick over for a while to let oil flow.
When switching off .out of gear let tick over before switch off.helps prolong life of turbo,maybe not so on more modern engines

 

[mikebeaches]

Manual gearbox vehicles I've always pressed the clutch before starting, to minimise the load on the battery and give the engine maximum spin. Not to mention the risk the vehicle was accidentally in gear. Habit began as a teenager, when all my old cars had dodgy batteries, especially when it came to the winter.

Rarely drive manuals now, car and van both have auto boxes.

In the case of diesels, it was my understanding the ignition should be turned on for a few moments before starting to allow the glow plugs to heat up.

 

[mikebeaches]

Duplicate post deleted

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[chatteris]

years ago when gearboxes used EP90 oil depressing the clutch reduced the drag of the gears turning in cold thick oil,these days the oils are much thinner so not needed now

 

[philw111]

I always start the car with clutch pedal down, having driven a lot of multi user cars where last person has left it in gear

I'm the same. Many years ago I worked for a car rental firm and quickly got into the habit of dropping the clutch before starting.

 

[Snowbird]

Holding the clutch pedal down is the correct way. It relieves stress on the battery and starter motor as it is not turning anything in the gearbox. I still see people starting a turbo diesel engine and driving off immediately without allowing the oil to circulate around the turbo. Same with shutting a turbo diesel engine down when hot. Always allow it to cool down a little before shutting down. Doing anything different in my day was a dismissable offence.

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[pyro]

Originally I was taught to depress the clutch to take the flywheel out of the chain, and make it easier to turn over. The fact that it also safeguards against leaving it parked in gear is a bonus

On diesels, I was taught to allow 20 seconds with ignition on, before turning over, especially if the engine/weather was a bit cold. A few years back I was told by a mechanic always to keep the foot off the accelerator on a diesel as you could damage the turbo if you revved high from cold (oil pressure)

 

[mjltigger]

My van has been parked up a few weeks so when I came to start it a few weekends ago it went like this..

Turn ignition on, check gear, wait for coil light, turn key
Swear
Clutch down, turn key
Swear
Clutch down, turn key, hold for 30 seconds
Swear
Turn off ignition, walk up the road and collect car, drive to van, connect jump leads, run car engine, turn ignition on, wait for coil light, turn key
Connect jump leads properly, ignition on, wait for coil light, clutch down, turn key
Swear quite loudly
Examine exposed fuel pipes.. No air bubbles
Turn off all ancillary devices and listen for fuel pump - heard
Lick up vehicle and drive to halfords for a can of cold start (swearing all the way)
Return home and collect SWMBO
Return to van with SWMBO and cold start
Start van

 

[jonandshell]

In theory, modern engine management should make it foolproof.
Turn key and go! There is nothing to discuss, it is all done for you. The only thing to watch is that your glow plug light has extinguished before operating the starter.

In practice, with a properly cold diesel engine, it isn't so easy.
At minus ten (or less!) with a completely cold engine I find the following works best-

Turn key, watch glow plug light go out, turn off, heat again, turn off, heat again. Clutch down, accelerator to floor, turn key to start position. Keep turning starter, keep accelerator to floor until the engine is firing on all cylinders. Ignore all the white smoke and misfiring at all times and keep that accelator planted until the engine runs cleanly otherwise the moment you lift off, it will stop.
Please note you do not rev the nuts off the engine from cold, all this takes place below 1200 rpm.

Something like this-

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[Enword]

Holding the clutch pedal down is the correct way. It relieves stress on the battery and starter motor as it is not turning anything in the gearbox. I still see people starting a turbo diesel engine and driving off immediately without allowing the oil to circulate around the turbo. Same with shutting a turbo diesel engine down when hot. Always allow it to cool down a little before shutting down. Doing anything different in my day was a dismissable offence.

I was taught to always depress clutch when starting, as was said before (EP 90) some of the plant was EP 120/140, in the depth's of winter it made the difference between starting or not starting, feels wrong with no clutch peddle, robotized manual gearbox.

 

[Boringfrog]

In theory, modern engine management should make it foolproof.
Turn key and go! There is nothing to discuss, it is all done for you. The only thing to watch is that your glow plug light has extinguished before operating the starter.

In practice, with a properly cold diesel engine, it isn't so easy.
At minus ten (or less!) with a completely cold engine I find the following works best-

Turn key, watch glow plug light go out, turn off, heat again, turn off, heat again. Clutch down, accelerator to floor, turn key to start position. Keep turning starter, keep accelerator to floor until the engine is firing on all cylinders. Ignore all the white smoke and misfiring at all times and keep that accelator planted until the engine runs cleanly otherwise the moment you lift off, it will stop.
Please note you do not rev the nuts off the engine from cold, all this takes place below 1200 rpm.

Something like this-

What's a glow plug light grandpa?

 

[jonandshell]

What's a glow plug light grandpa?

Not sure what you are saying. I am 45 years old and both my diesel vehicles, a 62 plate Nissan and a 10 plate Transit have a preheater light on the dash.

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[PP Bear]

Starting a diesel takes a lot from a battery, for that reason they're bigger and better than those batteries fitted to most petrol engines.

You can't take the flywheel, or clutch out of the chain, as its the flywheel that has the starter ring on it. The flywheel also houses the clutch assembly. On an automatic, it houses the impeller and vane assembly that allow for drive, once sufficient rev's are reached.

By depressing the clutch pedal (our military Kia's only start with the clutch depressed) you reduce the drag and effort that both the battery and starter motor has to endure by not turning over any internal components of the gearbox and drive assemblies. You are turning over the flywheel and clutch.

It's good practice on all engines regardless of fuel, to depress the clutch while cranking the engine.

Turbos have a number of systems fitted to try to help prevent the bearings running without oil. Best practice is to run the engine for a very short time to get the fresh oil around all internal parts (consider something like Slick50, as it does extend the life of internal components).

On closedown of an engine, you should let it ideal for a while to allow for cooler oil to circulate around and it assists in extending the life of the turbo.

One of the things that make me cringe the most, is those that drive the motorway at high speeds, then pull into a service station and switch straight off. With an engine doing say, 4500rpm, a turbo will be nearer 150,000 rpm and requires to slow down, cool slightly and have fresher oil delivered to the bearings

 

[jonandshell]

Both PP and I have seen some proper diesel engine starts.
Remember the clouds of smoke in Heavy 'A' at Bordon on a winters morning PP?

 

[pappajohn]

I'm surprised how many think pressing the clutch pedal removes the flywheel from the equation.....the flywheel is bolted to the crankshaft.
Depressing the clutch disengaged the gearbox and clutch plate only...even the clutch cover continues to rotate on the starter.

Phffft...ppbear beat me to it.

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[Boringfrog]

Starting a diesel takes a lot from a battery, for that reason they're bigger and better than those batteries fitted to most petrol engines.

You can't take the flywheel, or clutch out of the chain, as its the flywheel that has the starter ring on it. The flywheel also houses the clutch assembly. On an automatic, it houses the impeller and vane assembly that allow for drive, once sufficient rev's are reached.

By depressing the clutch pedal (our military Kia's only start with the clutch depressed) you reduce the drag and effort that both the battery and starter motor has to endure by not turning over any internal components of the gearbox and drive assemblies. You are turning over the flywheel and clutch.

It's good practice on all engines regardless of fuel, to depress the clutch while cranking the engine.

Turbos have a number of systems fitted to try to help prevent the bearings running without oil. Best practice is to run the engine for a very short time to get the fresh oil around all internal parts (consider something like Slick50, as it does extend the life of internal components).

On closedown of an engine, you should let it ideal for a while to allow for cooler oil to circulate around and it assists in extending the life of the turbo.

One of the things that make me cringe the most, is those that drive the motorway at high speeds, then pull into a service station and switch straight off. With an engine doing say, 4500rpm, a turbo will be nearer 150,000 rpm and requires to slow down, cool slightly and have fresher oil delivered to the bearings

So you think even with all these modern oils slick 50 is a good idea? And how long do you recommend sitting at tickover after a motorway journey?

 

[jonandshell]

So you think even with all these modern oils slick 50 is a good idea? And how long do you recommend sitting at tickover after a motorway journey?

Not everyone has the very latest vehicle on here.
Slick 50 had some quite good qualities in its day.
I always let a turbo engine run down whether it be idling along in second gear before stopping or a minute or so before switching off. A turbo is quite costly, it's worth the effort after a hot run.

 

[PP Bear]

Both PP and I have seen some proper diesel engine starts.
Remember the clouds of smoke in Heavy 'A' at Bordon on a winters morning PP?

Haha do you think he's left his IMH on!!

I remember Heavy A on a cold winters Monday morning, couldn't see your hand in front of your face with the 20+ lumps of heavy armour starting up. Good old days.

We did it once just before the new commandant came for his walk around. We wanted fume extractors fitted for good ole elf&safety. He never came back after that!!!

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[PP Bear]

So you think even with all these modern oils slick 50 is a good idea? And how long do you recommend sitting at tickover after a motorway journey?

I always use Mobil1 oil in all my engines, however I have still treated both the car and motorhome engines with Slick50 and you can hear and feel the difference once done.

Once you pull up after a long run, leave it ticking over for around 5 minutes. It'll pay in the long run and extends the life of a turbo and the bearings

 

[unimog]

My narrow boat engine started on petrol and then switched to diesel . It was a Kelvin J2 of about 1919 vintage . It was hand start.
Modern diesels should be given a few minuets at tick over after a motorway run to allow the turbo to cool down and slow down . Switching off the oil supply to a bearing doing several thousand rpm and at a high temperature can cause the oil in the bearing to carbonise and restrict oil flow in the feed and

return pipes

 

[grumps147]

In theory, modern engine management should make it foolproof.
Turn key and go! There is nothing to discuss, it is all done for you. The only thing to watch is that your glow plug light has extinguished before operating the starter.

In practice, with a properly cold diesel engine, it isn't so easy.
At minus ten (or less!) with a completely cold engine I find the following works best-

Turn key, watch glow plug light go out, turn off, heat again, turn off, heat again. Clutch down, accelerator to floor, turn key to start position. Keep turning starter, keep accelerator to floor until the engine is firing on all cylinders. Ignore all the white smoke and misfiring at all times and keep that accelator planted until the engine runs cleanly otherwise the moment you lift off, it will stop.
Please note you do not rev the nuts off the engine from cold, all this takes place below 1200 rpm.

Something like this-

There are so many 'tales' about how to do it. This is also what we have been told.

Our clutch operated VW estate required the clutch to be pressed before it would start. If you forgot, you got a message telling you it wouldn't start without clutch pressed.

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[TheBig1]

there was me thinking to start a real diesel engine, you switch on the ignition and crank the handle

 

[buttons]

Not read this thread so no idea what has been said but it will depend if it is direct or indirect. As far the clutch is concerned all new cars petrol or diesel now require the clutch to be depressed before allowing a start for safety reasons but depressing the clutch will separate the gearbox from the engine so requiring less energy to turn over.....

 

[gus-lopez]

TD I was tought foot off throttle ,clutch down to ease pressure on f/wheel & no drive .let it tick over for a while to let oil flow.
When switching off .out of gear let tick over before switch off.helps prolong life of turbo,maybe not so on more modern engines

My car actually has a sticker stating
"allow to idle for 2 minutes before switching off "

So you think even with all these modern oils slick 50 is a good idea? And how long do you recommend sitting at tickover after a motorway journey?

I do the same as the lorries. 5 minutes ticking over from cold start before moving off & the same at idle when stopping.

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