Cold start issues with a '91 350SDL

[engatwork]

I'm working on a '91 350SDL that the guy just purchased. It is showing 168k miles and is a beautiful looking/driving car that is clean as a pin. Unfortunately, it has a cold start issue. I just finished changing all 6 glow plugs (two were inoperative). I did not start the car up cold prior to changing out the glow plugs so I can't tell if there was any improvement or not but I'm sure there was some.

The car starts up immediately but after it has started it idles like crap and there is a good bit of smoke during the initial cold start. I pulled the valve cover and the chain is about 1-1/2 degrees off and it is quite obvious that someone has been changing the oil as they should because everything looks clean under the valve cover with absolutely no sludge build up.

After the engine is up to temp everything is fine. Is the rough cold idle an indication that this engine has gone the way of alot of the 350 six cylinders? Will a compression test provide a definitive answer in regards to this engine holding up its' infamous reputation? Anything else to test/check before I break the news to the new owner?

[larry perkins]

jim, i am just amazed that folks buy these 3.5 engines) and usually at a premium price) without reading about others experience.
i say the thing needs to be disassembled(open the can of worms) and see the total damage. i just finished one that had less milage than this one. probably got 5-6 k in it.
larry perkins

[DslBnz]

Originally Posted by engatwork

I'm working on a '91 350SDL that the guy just purchased. It is showing 168k miles and is a beautiful looking/driving car that is clean as a pin. Unfortunately, it has a cold start issue. I just finished changing all 6 glow plugs (two were inoperative). I did not start the car up cold prior to changing out the glow plugs so I can't tell if there was any improvement or not but I'm sure there was some.

The car starts up immediately but after it has started it idles like crap and there is a good bit of smoke during the initial cold start. I pulled the valve cover and the chain is about 1-1/2 degrees off and it is quite obvious that someone has been changing the oil as they should because everything looks clean under the valve cover with absolutely no sludge build up.

After the engine is up to temp everything is fine. Is the rough cold idle an indication that this engine has gone the way of alot of the 350 six cylinders? Will a compression test provide a definitive answer in regards to this engine holding up its' infamous reputation? Anything else to test/check before I break the news to the new owner?

Depends:

Here's mine just before the engine transplant. Is it like this?

http://www.zippyvideos.com/6161441694710296/350klocker2/

That engine was toast.

[joegolden]

UGH that is a scary motor. Kinda sounds like mine at cold start up. Mine does not shake after it is started tho. Wow. So how does it run now? Got video? That was cool.

[engatwork]

Went out and started this morning and it did great. During the troubleshooting yesterday I changed out the pre-fuel filter. While changing it out I noticed that it looked like the line coming to it had been leaking. Repaired this leak and it looks like the cold start issue is now resolved.

[mbenzer]

See my Thread, "350SDL--is this the beginning of the end?" The first sign I had was a plume of white smoke upon cold start accompanied by rough idle for about 10 to 20 seconds and then it smoothed out. My 350 has approx. 138K miles.