Old Diesel warmup time - PeachParts Mercedes-Benz Forum

Meridivs · #1 11-22-2005, 07:14 AM

What would be, from your experience, the best way to start and idle your Diesel engine to warm-up before leaving?

This is my first winter with my 300TD '79 Estate (617.912 engine) and it seems that now I have to press the acceleration pedal before turning the key to start when the engine is cold.

I remember that VW recommended a time from 2-3 minutes of warmup idling for their diesel engines before leaving but I need to know what's best for a Mercedes Diesel which acts and feels pretty much different from it's VW counterparts.

#2 11-22-2005, 07:26 AM

I usually go by the temperature.
The colder the temperature, the lower the warmup time and visa-versa.Although I am not always exact I find my 'rule of thumb' is to let it warm up for five minutes when it is 0 C and roughly an additional minute for every degree colder.

vwbuge · #3 11-22-2005, 07:38 AM

I really don't run mine in the cold or snow but when it is chilly outside I usually let it idle for as long as possible. If the block heater is needed and it is your main winter ride I would let it idle for at least 3-5 minutes.

t walgamuth · #4 11-22-2005, 09:21 AM

glow, start, fasten belt, go. if it is really cold i wait 30 seconds or a minute. then no full throttle right away.

tom w

Meridivs · #5 11-22-2005, 09:35 AM

That's how I wrecked my previous car - a VW Golf II TD. After 3-5 months it developed all sort of odd problems like refusing to start easy when hot (damaged piston ring), bad injectors (it sounded like a T34 after every long 500Km+ road) and so on.

The Mercedes only stumbles and clatters like hell when cold. I only go faster when I start it in a supermarket parking and I have space to run it around for a few minutes before going for the main road. It has a pretty steep exit and I don't dare to attack it with a cold engine anyway.

The problem with starting right away is that no one is willing to wait for you to warmup your engine in traffic, especially during rush hours. Sometimes you have to rev it within as little as 2 minutes from starting.

dannym · #6 11-22-2005, 09:42 AM

Whn I lived up North I warmed up until I saw the temp needle begin to move. After while you get a feel for how long it will take for varying temperatures.

Remember, heating the engine doesn't warm up the transmission. The best way to warm up a car is to drive moderately until the temperature get's up to near normal.

Danny

Glinko · #7 11-22-2005, 09:55 AM

I start it, and as soon as the engine is fired I put it in low gear and stomp the pedal into the floor.

MB-Owner-in-ind · #8 11-22-2005, 12:44 PM

I usually run mine for what I feel is long enough for the oil to get going. Then I take it easy. These diesel won't really warm up until you use them. I once let the car idle for 20 min in the cold of winter and still it didn't get much off the bottom peg of the temp gauge.

#9 11-22-2005, 12:49 PM

If it's cold (below freezing) I usually let it warm up for 5 minutes or so, mostly to get cabin heat sooner. Then I try to keep the revs down for the first minute or so of driving, until the temp gets up to about 60C.

braverichard · #10 11-22-2005, 12:52 PM

I just do like someone else has stated here: turn key to glow position, put on seat belt, crank the sucka and drive off slowly. By the time I get to the highway, temp gauge will be just below 80 C so I can do highway speeds safely.

Just about anything is better than the typical practice of just starting the engine and letting it run for several minutes to warm up as people do with gasoline engines. Try that in your diesel and you'll just start choking up the engine. Additionally, while a gasoline engine can attain optimum operating temperature just by idling for a brief while, the same doesn't apply to diesel engines.

Hatterasguy · #11 11-22-2005, 01:32 PM

On real cold days 20 or colder I will let it idle for 5-10 in the morning to bring the temp up a bit. Other then that just keep the rpms down until the temps come up. I pretty much stay off the turbo until the oil pressure drops off.

Meridivs · #12 11-22-2005, 02:17 PM

I've noticed the same thing: 5-10 minutes of idling can make the temp gauge move a bit but 10 or more won't push it higher at all. For now I'll stick to 3-5 minutes of idling and 4 running around the park lot in 1st gear

)

phidauex · #13 11-22-2005, 03:57 PM

Great advice from the guy who wrote the famous "keep your beetle alive" book that every VW bug owner should have:

Get in, start the car, roll a cigarette, and once you get it drawing nicely, drive off.

Seriously though, too much idling is bad, they won't warm up, they'll just wear the engine. I fire it up, let it warm up for a minute or so, and then be gentle on it until the temperature comes up. Sounds reasonable to me.

peace,
sam