I was wondering if a 1987 300D is supposed to emit smoke when it is idling after it has warmed up? One of the past 300D's I looked at seem to emit a small amount of soot at idle even after warming up. I know there is supposed to be some smoke at idle when the engine is cold.

Is there any time a 300D should smoke or is it fairly clean burning? (like during hard acceleration?)

Thanks in advance.

-Steve

Swogee:

I also have a 1987 300D and we may be able to exchange info that maybe useful.

When I start my engine in the morning, it runs rough and it blows blue and black smoke. It does this until it reaches full operating temperature, a little bit over the 80 degree mark. Then it has almost no visual exhaust smoke.

However, if I gun it from a green light, and look in my rear-view, I will see a small amount of black smoke. No other time after it is warmed up, even sitting idaling, do I see any smoke at all.

What does yours do?

My SDL (same engine as your 300D) makes a little bit of dark smoke at idle... probably due to timing chain stretch, although I haven't checked the chain stretch yet.

My SDL makes a little bit of light grayish smoke at idle. It only does this when it's warm, but not all the time? Can't worry about every little noise, leak, smoke or rattle. There old cars things are probably getting a little tired. Maybe the timing chain is stretching? I'll see if theres a difference when I do mine in a few months.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

My OM603 both smokes (grey) and idles rough. I've checked chain stretch, replaced injectors/gp's/engine mounts and adjusted the IP timing. I haven't done a compression test yet, but I really suspect my problems with smoky roughness are caused by an IP needing new delivery valve seals, and/or a re-calibration at a Bosch shop.

hello,
well another thing to factor in is operating temp., both my diesels I've noticed they both smoke at idle alittle, and with everything in good shape, pumps, injectors and etc, remember, when sitting an idling, your losing operating temp, diesels cool down when idling, cause your no longer making the engine work. What I've noticed is when the temp. drops below about 185f I see poofs of smoke, and when its back up to around 195f, no smoke unless I stomp on it. to me diesel seems to burn best between 195f-205f on my temp. guage. just my .01 cents worth.

I too was a bit surprised at the level of smoke from the 603, both cold and after fully warming. When cold, it emits a moderate amount of blue/gray exhaust smoke that is significantly more than the low level that the 617 emits. When fully warm, it emits very little smoke, but, still visible, and, more than the 617.

What kind of fuel economy is everyone getting with there 603's ??

I don't know what the weight difference is between the 300D and 300SDL, cant immagine too much, but I seem to get a consistant 31.4 mpg with combined city/hiway driving!

I have heard somewhere sombody claiming 40 hiway!

I don't get much consistency, but I do usually run between 27-33 mpg. I have a hard time keeping my foot out of it though, as all that delicious level of torque is too much temptation for me. My wife's Passat tdi is actually quicker from 0-60, but the 300 td just feels more impressive as it accelerates.

I'm only getting 22-23. About 60% around town and the rest highway, at about 80-90mph. Maybe I should keep my foot out of it for a tank and see if that improves. Or dare I say drive 60 on the highway

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Well, I just ran the SDL for about 875 miles over the holiday. With the A/C on and running 85% highway miles she got 29.50 after adjusting for the odometer error. I have confirmed that the odometer reads 6.5% more miles than the vehicle actually travels. Interesting. The SDL has a weight of about 3850.

I forgot to mention that you can also reduce the amount of smoke (and roughness) from cold starts by snipping the violet wire on the GP relay. This allows the GPs to stay energized for a longer period than originally designed, thus maintaining heat in the prechambers while the engine warms up. I placed a thermally switched relay into the violet wire circuit so that the GPs wouldn't glow for that longer period after the engine temp reached 50 C.

The door frame on mine says something like 4300lbs. I'll check it later.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

My 86 300sdl has about 131,000 miles. It smokes on start up. Seems to be diesel smoke. I haven't noticed any blue or white. The only other time it smokes is if I floor it on the highway. A nice feature if someone is tailgating me. My last tank of 70% highway driving returned almost 25MPG. City driving is 22-24MPG.

BTW the valve seals were replaced by the dealer shortly before I bought the car.

Dave

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1986 300SDL

4,300 lbs sounds a bit more like it for the SDL. My Volvo 240 wagon was 4,100 something. I haven't looked at the door emblem yet on the 300D but I'll bet it is all of 4,000 lbs.