I have 140k miles on this car. Its been sluggish when cold here especially now that cold weather is here. The car has had a slight surge for a while now too. It had a fuel filter at 108,000 miles in November of 2003 ? Any suggestions ?

Waxed-up fuel filter(s).

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OH it's 53 right now but it was 30 degrees this morning. I think a fuel filter may help the cold performance but I dont think its going to fix the slow speed surge.

Its about 53 degrees now but it was about 30 this morning. I think a fuel filter may sollve the cold performance problem but Im not sure about the surging when hot.......thanks for the response.

All diesels are low on power (in Texan: giddyup) when started cold on a cold morning. I've read the block and head are absorbing the heat, reducing what's available to expand the combustion gases and produce power. Sounds reasonable. Whatever, all the diesels I've ever owned exhibited the behavior. If you think your modern om606 turbo is bad, try one of the older cars!

- JimY

I agree. All diesels are slugs when cold.

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I have a related question: is there any valid, technical merit in allowing a cold diesel to warm up before driving it, even for just a minute?

Is it ok to "floor it" even when its cold?

Normally I baby the car at least until the air starts blowing warm from the heater.

thx

There's no reason to let an engine warm before driving off. So long as the oil pressure has come up and the various internal bits are being lubricated, it's time to move off. Typically starting the engine, then fastening your seatbelt, checking mirrors, selecting a radio station matching your current mood, etc. allow sufficient time.

It don't think letting a diesel idle for a few minutes is harmful to the car, unlike a gasoline engine. On a gasoline engine, the cold engine causes the fuel to condense on the walls of the intake manifold and/or cylinders. There it washes off the oil film, and eventually runs down into the crankcase, diluting the oil. This process has bad effects on engine life. The strategy to maximize engine life is to minimize the time the engine spends cold. Driving off as soon as possible warms the engine much faster than letting it idle.

From another point of view it's undesirable to let any car - gas or diesel - warm at idle because it consumes fossil fuel and generates air pollution without providing any transportation. Idling cars all get zero MPG.

I could ramble on longer, but this seems sufficient.

- JimY

I idle my car in the garage when I found out the block heater was not working.


This way I have it ready to go in the morning.

Only problem is that the neighbors thought someone was commiting suicide.......

We started our 83SD cold and tried to drive it up on some ramps...it got half way, growled there for a bit, then rolled back down, pedal to the floor It just couldn't do it....I bet it was putting out like 25-30hp at that point. Mine is the same way, extreeeemely slow take off when its frozen, but within a couple mins of driving its doing fine, and its only on the real cold mornings when its 30 or less out that its real noticeable.

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I have not really noticed my 603 acting any differently when it is cold. But I never let it over 2k rpm until it is warm. Not only the coolant but more importantly the oil, I won't get on it until it is idleing at 1.5bar. Turbo's spin real fast and don't like cold oil, getting on a cold turbo engine is a real bad idea.

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Yeah, here in Northern California it's been getting around that same temperature... just let her warm up I dont see much wrong with flooring my car when when cold, since it doesn't even respond very much! I noticed a lot of white smoke too this morning while letting the car idle for around 6 minutes or so.

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As a M/B tech I'd agree that sluggishness while cold isn't out of the ordinary but sluggishness with a low speed surge would concern me. I've known a few OM60x.xxx diesels that exhibited this behavior right before a timing chain breakage. You could have a stretched chain that's getting ready to let go The newer diesels are not typically as sluggish cold as the older ones. You have relatively low mileage so your engine should be good and strong. I'd have the timing chain (and tensioner, and cam gear bolt, and rails ) checked ASAP and replaced if warranted. It might sound like I'm trying to scare and to some extent I am. I have a OM603.971 diesel on the engine stand right now that broke it's chain at 80k unabused original miles. It's gonna have a 7K$ repair bill to fix. Compare the price of a chain and tensioner to an engine and then get your car to a shop to have it checked. ASAP

Diesel engines are very sensitive to temperature. They do not like to be cold or too hot. You should always warm up the engine before driving it in the winter, and if you can't, do not drive it at rpms where the turbo is creating boost. A cold start and then promptly "flooring it" will destroy the insides of the engine. The show "Trucks" on spike covered this once, and the cylenders of the engines treated in this manner were shot.

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