warm diesel drive off?

Jeffrey · Nov 23, 2004

I don't know... seems to me that with a modern passenger diesels it really isn't that inconvenient. Wait about 20 seconds at start up for the oil to circulate, wait about one minute if I've been driving at speeds over 100 kmh, less than that and wait about 20 seconds.

One thing is certain, I don't miss the extra stops at the gas station that I had with the gas engine!

Rat407 · Nov 23, 2004

quote:

Originally posted by Jeffrey:
I don't know... seems to me that with a modern passenger diesels it really isn't that inconvenient. Wait about 20 seconds at start up for the oil to circulate, wait about one minute if I've been driving at speeds over 100 kmh, less than that and wait about 20 seconds.

One thing is certain, I don't miss the extra stops at the gas station that I had with the gas engine!

Wouldn't work with my wife, runs late going everywhere, from kids to school, picking up from school, piano practice, soccer, physical therapy appointments, doctor appointments. So it is jump in start, drive, shut down. 20 seconds is a lot to ask.

bulabula · Nov 24, 2004

On my Dodge CTD, I was led to believe that the concern on cold starts is fuel washdown into the crank case. The expansion coefficients of the aluminum pistons is different than the iron block, so the idea is to be able to warm up the engine to normal temps quickly but gently. Prolonged or extended idling isn't the answer (not to mention wasting fuel).

Once the engine starts and oil pressure comes up and stabilizes, I drive off gently and don't exceed 1800'ish rpms until the temp needle comes off its stop (around 140F). Once that temp is met, I pull the trigger and let her rip.

hone eagle · Nov 24, 2004

bulabula. I am with you ,start ,wait a bit ,drive away s.l..o.w..l....y. besides if i wait around too long school kids come runin

Jeffrey · Nov 24, 2004

Ah, hadn't thought of it that way!

I see your point.

Spitty · Nov 24, 2004

I thought that people ran there Diesels for half an hour each morning just to pi$$-off their neighbours

.
I think a lot has to do with hrear-say and folk-law "Dad used to warm up his D8 Cat for 15min befor useing it, so I'll warm up the Dodge for 20"

Marshall Booth · Nov 26, 2004

While it's possible to make a case for warming the cold engine at idle before driving OR driving so it warms up quickly, Mercedes has recommended the latter strategy for their diesel engines for more than 30 years.

Their recommendation is to drive the cold engine as soon as oil pressure pegs the needle at 3 bar (45 psi) but to not push to anywhere near the limits until it reaches operating temperature. The critical factor is to minimize the excessive wear that occurs with the engine runs at less than operating temperature and the fact that the diesel engine produces very little heat at idle. This results in MORE wear with then engine warming up at idle temperature than when the engine is moderately loaded (and warms up much more quickly).

Marshall

widman · Nov 27, 2004

With my Turbo Diesel 4Runner I start the engine, plug in my phone, put on sunglasses and let out the clutch enough to get from the level garage to the sloped driveway out onto the street. Then drive the single lane cobblestone road in 1st and second for the 600 meters to the other end of town through the children and sheep. By the time I reach that end of town the temperature guage starts to climb and I hit 3rd accelerating only lightly until the guage is all the way up. By the time I get to the bridge at the bottom of the mountain I have full temp, so I can go like crazy for the remaining 20 km til I get to my office, where I leave it idling and cooling until an employeed takes it to wash it or park it.

Silk · Nov 28, 2004

I just start and drive my diesels,(quietly),the Pajero has a turbo timer and I usualy set it to one minute as it gets cool down driving in the city before I stop,if run hard straight to a stop I'll give it longer.My 19 year old daughter drives a diesel Laurel,you can guess what she does.

My Nissan Vanette is a hard starter,needs a good 15sec glow,runs well for a minute,then as the glow cools it runs rough and blows white smoke - you can idle it for 5 mins and it will still put out heavy white smoke,but shut down after a minute,then restart after 3 mins and it runs ok - the heat soak will warm the combustion chamber.Diesels will take a long time to warm at idle,they warm under load.This is also a symtom of retarded timing - although the timing is correct,I may advance it a bit,this will make it put out more black smoke under load,but improve cold start.

steiner43511 · Dec 11, 2004

in the summer i usually start, wait 30 seconds and then drive off with my 6.5 turbo diesel. in the winter i plug it in, start it run it for 5 or ten minutes then drive off. i installed a high idle switch a while ago and that makes it pretty nice. go out start it, flip on the 1100 rpm swith, go back in and finish gettin my stuff loaded up and take off. i also have a post turbo pyro and wait till it is below 300-350 to shut down.

Gene K · Dec 12, 2004

Dont know about Light Diesels but on CAT Heavy Diesels Owners Manual says warm until the engine will idle smoothly then drive gently until the water temp starts to register and then you can go to full load.

Personally I usually warm at least 2 minutes below 40&#176F (4&#176C) and avoid full throttle until showing at least 160&#176F (71&#176C).

Gene

Chris Heckman · Apr 17, 2005

Letting any vehicle idle more then 5 mins is a waste of fuel. It usually takes about 30 seconds in the winter for my idle to stabilize. I tend to take more time then that though cleaning off the car. No point, it just waste fuel as has been discussed no diesel will ever fully warm up to oper. temp. at or below freezing. If an engine does not have FULL cold oil pressure within 10-15 seconds you have a problem.

I do not like the fact that the Hyundai has noisy lifters only on engine deceleration. It has done this since day one. Usually bad lifters hydrualic or not make noise all the time. These just do it after letting off the gas. Oil pressure has been checked and is great, same with compression.

I just do the recommended with my TDi which is keep it under the after glow cut off. This is around 2500 rpms. After the temp. gauge rises out of 3 white marks procede to shift at 3000 and let her rip once warm. Since I drive a manual and have coolant glow plugs. I get very lukewarm heat within a minute. Since I have a short drive I don't bother turning it on at all. If it's longer then I keep it on low untill it's warm enough to make a difference. That usually takes a while in the city. I wish I could plug in but thats not an option on my block.

Edit: Also for OP if you had metal filings in your pan because you just drove off on a fully warm engine. You have bigger problems I would think.

Gurkha · Apr 17, 2005

I have it quite easy this way, my house is all the way up on hill so when I start my day, it is all downhill with very little or no load on the engine, that way it warms up nice and easy by the time I reach the highway.

My MB engined vehicle heats up nicely, the problem is the HINO engine on my Nissan Patrol, that takes forever to heat as it is a truck application engine with 11 ton rating. The cooling system simply can not get the load necessary to come to operating temps in the winter.

Shannow · Apr 17, 2005

IMHO (and it's an "O"),
heat losses are proportional (give or take) to heat input, i.e. fuel input.

If you are idling an engine, it has the absolute minimum heat input, and heats up very slowly. Light load may have 5-10 times as much heat input, and therefore heats quicker.

In the mean time, you have greater cylinder pressure, so have more load on the oil.

And the EP adds don't work unti 75-80C.

In my cliamte, I'd rather get the oil pressure up, move off, and then lightly load until I see the temperature gauge move (i.e. the ring and cylinder surfaces have attained some temperature) before I give it some load.

Question: when is your crank/cam/head thermally stable ?

Ugly3 · Apr 17, 2005

quote:

Originally posted by Gurkha:
I have it quite easy this way, my house is all the way up on hill so when I start my day, it is all downhill with very little or no load on the engine, that way it warms up nice and easy by the time I reach the highway.

My MB engined vehicle heats up nicely, the problem is the HINO engine on my Nissan Patrol, that takes forever to heat as it is a truck application engine with 11 ton rating. The cooling system simply can not get the load necessary to come to operating temps in the winter.

I would think with the thermostat closed the size of the cooling system would be a very small factor in the warm up process.

Gurkha · Apr 18, 2005

You are right, the thermostat never gets a chance to never gets the heat to open up, but that is due to the engine and the cooling system being too big for the load on it.

Shannow · Apr 18, 2005

Gurkha,
same with my old BJ42 cruiser with the 3.4 litre 4 cyl diesel (3B, also used in Diahatsu trucks). Huge donk, huge water capacity, low powered.

Took forever to warm up.

theguru · Apr 18, 2005

Your drivechain will never heat up with the vehicle sitting in the drive.

Gurkha · Apr 18, 2005

Shannow,

The HINO is 4 liter, 4 cylinder 135bhp engine with a payload of 11 ton, out in the relatively small Nissan Patrol body, it just simply lazes at idle while on plains even with an antiquated 3 speed transmission.

Gurkha · Apr 19, 2005

268lb/ft at 1200RPM. Goes up to 310lb/ft if you add a turbo from the factory.

warm diesel drive off?

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