# questions concerning diesel engines



## jblimbwalker (Apr 23, 2003)

First question: Is it necessary on diesels with intake heaters to wait for the intake heater dummy light to turn off before start up?It comes on upon turning the switch on and goes off after a few seconds. I don't know if it matters, but this particular truck is a '93 Chevy Kodiak. Our bucket truck is a '02 International and although it doesn't have an intake heater/glow plug light it will make a ticking noise (approiximately eight ticks) upon turning the switch. Should we wait for this ticking to cease before turnin' her over? Before someone asks, I have looked for the owners manual on both trucks and of course they're missing. OK...Second question: Should a diesel truck engine be allowed to run the majority of the work day? I've heard it is not good on a diesel to be shut down and restarted repeatedly. What harm is done...if any? Third question: Before shutting the trucks down for the day should they be allowed to idle for a few minutes? I used to work for a guy who would let his diesel trucks idle for ten to twenty minutes before shutdown, but he couldn't tell me why. Please allow me to slip in one non diesel related question related to chippers: Should the engine be throttled up slowly after the clutch engagement, or can you simply engage clutch and 'rip' the throttle? The chipper in question is a Vermer 1850. These questions have puzzled me for awhile, some for years and I figure _this_ is the place to ask. Thanks, in advance, for any replies.


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## spreaderman (Apr 23, 2003)

*turbo ???*

if the diesel has a turbo charger on it, it is ideal to let it idle two to three mintues to allow the turbo to cool before shutdown or over time it will cook the turbo..........starting and stopping a diesel is not hard on one, just idle it for about a minute the first time you start it up in the morning especially if it has a turbo to allow oil to get up to it........(don't rev start it) I'll let someone else come in now


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## Menchhofer (Apr 23, 2003)

My mechanic tell me if the diesel has a turbo and you have been running interstate speeds, then yes allow it to idle for a couple minutes to allow the turbo to cool down. Normal everyday driving should not affect it.

I use to let my diesel engines idle before I would shut them off, but now I have been told that was for the older models. For the past 4 years I have been turning them off like a gas engine.


Owners manual with my diesel chipper only states rpms should be below 1,000 before engaging / disengaging clutch. John Deere diesel manual says do not idle engine for more than 5 minutes. Either shutdown or increase rpms slightly.

Always warm up chipper engine and hydraulics before full throttle also.


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## dbeck (Apr 23, 2003)

When i worked for a utility contracting company, it was mandatory to idle the trucks until you could see the temp gauge move. also, warm up time was mandatory. the trucks were started as soon as somebody from each crew arrived, 1st one there atarted that crew's truck.
this is the way i look at it, i don't get up in the morning and run full bore, why should my machinery?


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## Acer (Apr 25, 2003)

Not sure about the light for intake heaters. With glowplugs, you wait for the light to go out before starting. I don't think it harms if you can't wait for that..just difficult to start from cold.

The ticking noise you describe might be the sound of an electric diesel lift pump.

With a turbo, on some engines, you need to let it idle while the turbo slows down. Switching off the engine will cut lubrication to the turbo, but if you've been running at full revs before, the turbo will still be spinning quite fast, without a good supply of oil. 

If your Vermeer chipper has a belt drive between engine and disc, it's best to be as gentle as possible. I've seen people engage those at full revs, or whack the throtte to full as soon as possible, which causes clouds of smoke as the belt burns up.


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## ksu_chainsaw (Apr 25, 2003)

we have a lot of farm equipment that is run by a diesel engine and we let it idle for at least 10 minutes each morning befor we go to work. it also depends on the outside temperature how long we let it idle. we also let it idle down at night for at least 10 minutes to let the turbo wind down. 

We also have a 89 ford diesel- non-turbo model. it ticks when turning on the key because the glow plugs are cycling. this happens after the wait light goes out. we turn the key on and wait for thecliksing to stop, turn the key off and back on, wait for the clicking to stop, then start. This works most of the time, but if it's too cold, it takes forever to start.

Charles W


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## DDM (Apr 26, 2003)

Charles, Ive Learned that if its going to get below 30 Deg I better plug my Ford diesels in. Thank God for that Plug hanging under the hood.

Anyone that Needs More Diesel advice should check out http://www.Shopdiesel.com


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## Lumberjack (Sep 19, 2003)

We start our diesel engines right off if it is super cold, not here in MS, then let the glow plugs heat up and warm the air and then let it crank. As for shutdown if it has been working hard then let it idle for 2-3 min to let the oil cool down and that will also cool off the turbo. If you don't then the oil that is trapped in the turbo will actually cook in the turbo because the oil isn't flowing through the turbo and the oil in the turbo will become the same temp as the turbo, possibly over 1000 degrees. On the first start of the day let it get the oil pressure up and let it warm up a little.

Carl


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## Crofter (Sep 19, 2003)

Idling beyond a couple of minutes is often not recommended. A lot of modern diesel engines are vey slow to come up to temperature at idling and in cold weather can cool off at low idle and have cylinder washdown and dilution of engine oil. Let them idle down a few minutes before shutting off and mandatory idledown of turboed engines. The exhaust side of the turbo can be over 1000 deg. F. and if you shut it down immediately there is no more oil flow or air flow and the heat will travel into the bearings and seals causing cokeing of oil and seal damage. You can get away with it quite a feww times and think this is ok, but you shorten the turbo life.

Frank


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## earache (Sep 20, 2003)

Very good questions. Yes, always wait for the light to go out before cranking the engine. On the other one, what model International is it? What engine is in it? That engine probably has no preheat system. The eight clicks you hear is the ABS modulator valves going through a self test. I would guess it is a Class 7 or 8 truck with air brakes. If this is the case, there is no need to wait, just crank and go, although a block heater is highly recommended for ease of starting. . Not all diesels have a preheat system. Do not idle you're diesels any more than necessary. Obviously for warm up in the morning, and that is it. If a diesel is allowed to idle for long periods of time, wet-stacking occurs. Wet-stacking is when all fuel delivered is not burned, and is expelled through the exhaust valves, through the turbo, and out the exhaust. You may notice black liquid around exhaust manifold gaskets and turbo joints. 
This is due to incomplete combustion. You may want to idle you're diesel after a long, hard pull before shutting off, but it is not necessary to idle for a long period of time. With the advances in oil and bearings, there is really no cause for worry at all. Hope this helps. Please feel free to e-mail me with any other concerns.


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## Dieseldog (Sep 27, 2003)

Limbwalker These are all good questions with answers that can lengthen engine life if followed.1st the 92 Kodiak I suspect has a Cat 3208,(T) or a 8.2 Detroit or possibly even a Deutz diesel ( I think only available in the US which may have an intake heater) and if it does come equipped with one you should always allow it to fully cycle before cranking.Also cranking for 5 to 10 second intervals with 5 second rests inbetween allows the heat of compression to dissipate into the cylinder and the starter to cool in cold weather aiding in quicker starting with less strain.Remember never use ether with an intake heater or risk an explosion unless the intake heater is disconnected first.On the 02 IH I suspect it has antilock brakes (air brake) and is doing its system check clicking the air solonoids for each wheel in its start-up .This is normal.On the third question about tempature and and engine shut-down the rule is if turbo-charged the engine must be cooled down to 180*F or less usually at a medium or idle no load.This prevents coking of the oil in the turbo shaft and bearings which can cause future turbo failure.Diesels can run all day as they are designed to do this even at max goverened full load for their entire life!The problem is some engines may run too cool or even to hot at idle depending on design and ambient temperature.Here the rule is always to keep them at a fast idle when idling or running at light load such as 800 to1200 rpms.This will allow sufficient heat build up for efficient combustion and speed for cooling.As for speed at engagement of accessories it only makes sense that doing it in steps will lessen the strain on the engine and belts resulting in longer life.Engines such as ones driving gensets or emergency vehicles start and go to max rpm under full load for obvious reasons but make no mistake theres a trade off. Thanks Dieseldog!!


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## bwalker (Sep 28, 2003)

I only allow the the grid heater on my cummins to cycle if it is under 30 degrees. I also allow it to idle for 5-10 minutes on cold mornings with my high idle device set at 1800 rpm. Its is warm whem I get i by then


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## Koa Man (Oct 13, 2003)

Regarding turbo diesels, the best way to know when to shutdown is by installing a pyrometer to measure the EGT (exhaust gas temp) EGTs should never exceed 1300 degrees if temp probe is installed preturbo, or 1000 degrees if installed post turbo. Temps exceeding that can melt your pistons. When idling down you should wait for the pyrometer to read 300 degrees before shutting down. On my truck after pulling a big hill with a load, that can take over 5 minutes. Big rigs normally come with pyrometers installed post turbo. I install pyrometers in all my turbo diesels preturbo because it gives faster temp changes and the EGT readings are more accurate.


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## Wolf66 (Oct 15, 2003)

On all my diesels, the light that goes on and then comes of is the glow plugs warming up. It is to my understanding that you should always let this occur before starting. I have been told by a truck driver that the reason people let those diesel motors run all day has to do with fuel consumption, that they will actualy burn more fuel if you turn them on and off several times daily that will burn more fuel than letting them idle all day. I still let tree equipment cool off during the day, but my track loader and backhoe I allow to run all day without incedent. But these machines are old and hard starters and thats the main reason why I do it.


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## Koa Man (Oct 15, 2003)

As crofter mentioned above, you need to be aware of cylinder washdown when idling a diesel and the engine gets cold. Unlike gas engines, diesels get colder the longer they idle at low speeds. Trucks idling all day such as refrigerator units etc, have an idle controller than boosts the idle speed up to 1200 rpm for that very reason. Very bad to let a diesel idle for long periods at normal idle speeds of 700-800 rpm. Unless you are starting and stopping the diesel engine every 5 minutes or less, it is far more economical to shut it off.


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## maggiesboy (Nov 3, 2003)

*oil cooldown time*

The term that was used by cat and cummins in tech school was coking the oil. much like cooking but they say it is coking. Why I don't know, other than sludge build up. The instructors were very clear that cool down time is indeed needed. Bill Jr


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