Shake n' shudder on cold startup ... normal? Worrisome? - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 12-03-2005, 03:37 PM

How normal is it for my car's engine to bust out two or three big shakes after a cold startup (below 20F at least). It's done this for a while. No problem starting at all (knock on wood), and it doesn't seem to have an audible knock. After it sits for 15 or more hours, it REALLY shudders even though it starts easily. Usually it just gives one or two big shakey surges and then continues on smoothly. I'm not an expert at identifying unusual sounds, but at idle it really sounds fairly smooth even while warming up. It does vibrate some, but I had the motor mounts replaced just last week and the vibrations have noticeably reduced at warm idle and upon deceleration (where the vibration was before). Once it's warm, no shaking on startup. But after it sits for a long time it tends to do this even when it's not terribly cold out (I'd estimate it does a shake or two at any temp under 40). It much more noticeable though when it gets really cold. Sometimes, like today, it will shake five or six times and then continue on smoothly. Is it misfiring? Is this a problem? Or is this just a matter of "it's a diesel, it's old and it's cold ... live with it"?

Adding as an afterthought, the shakes happen after I have turned the key and let go of the key ... rather than DURING startup.

t walgamuth · #2 12-03-2005, 05:49 PM

i think.

first glow plugs. one or more is prob bad.

if not that then possibily a small air leak in fuel line.

first choice since it is temp sensitive is glow plugs.

tom w

Hatterasguy · #3 12-03-2005, 05:52 PM

It could be a weak glow plug, or a leaking delivery valve seal. Both are pretty cheap and simple fix's.

If not all 603's seem to skip/rumble a bit on cold starts. Just bring the rpms up to 1k or so and it will clear right out. The only real solution that I could come up with is an IP rebuild but that may not even solve it.

boneheaddoctor · #4 12-03-2005, 05:52 PM

I'll agree....you've likely lost one maybe 2 glowplugs.....so one or two cylinders don't fire off right away..

Brian Carlton · #5 12-03-2005, 05:57 PM

It is first necessary to verify if the condition is "typical 603" cold starting behavior or whether there is a real problem.

So, next time you have a real cold start (35°F or less) and it has been sitting overnight, turn the key to the #2 position and let the glow plugs light up and remain lit for 35 seconds. Use a watch.

Then start it.

If it runs perfectly smooth, then the behavior is "typical 603" cold starting behavior and you simply need to run the glow plugs longer.

If it kicks and bangs like it did previously and then runs smooth, then you likely have one or two weak, or bad, glow plugs. You can test this, yourself, if you have a meter that measures resistance.

BodhiBenz1987 · #6 12-03-2005, 10:40 PM

Thanks guys. Will do the necessary experiments. My dad thinks it's glow plugs as well. I've been amazed at how loyally this car has started in freezing weather (last winter it had NO PROBLEM starting at -7F), so I kinda figured sooner or later the 19-year-old glows would go ...

rg2098 · #7 12-03-2005, 11:53 PM

My 617 does the same thing. All 5 glow plugs were just replaced and reamed out, helped a ton, but still there on the cold mornings.

Johnhef · #8 12-03-2005, 11:59 PM

Quote:

Originally Posted by Hatterasguy

It could be a weak glow plug, or a leaking delivery valve seal. Both are pretty cheap and simple fix's.

If not all 603's seem to skip/rumble a bit on cold starts. Just bring the rpms up to 1k or so and it will clear right out. The only real solution that I could come up with is an IP rebuild but that may not even solve it.

I'll agree with this- my 603 was the same. for awhile i'd just rev it up and it would idle fine afterward, but I added in the cord for the block heater and just used that to help it out and it would always run smooth.

It never did have a problem being too cold for it to start.

whunter · #9 12-04-2005, 12:01 AM

Glow plug testing.
Glow Plug Testing?

Don't always trust your glow plug indicator light!
Don't always trust your glow plug indicator light!

Glow Plug Relay
Glow Plug Relay

New Glow Plug kit installation. 1978 240D
New Glow Plug kit installation.

Glow plugs link thread
http://www.peachparts.com/shopforum/diesel-discussion/137732-glow-plugs-link-thread.html#post1019018

Replacing Glow Plugs
http://mbdieseldiy.tripod.com/glowplugs.htm

dieseldiehard · #10 12-04-2005, 02:04 AM

Quote:

Originally Posted by Johnhef

I'll agree with this- my 603 was the same. for awhile i'd just rev it up and it would idle fine afterward, but I added in the cord for the block heater and just used that to help it out and it would always run smooth.

It never did have a problem being too cold for it to start.

The 603 starts much better than my 617 in cold weather. 17 degrees is the coldest I have experienced in my 300TD (617) it was a PITA to get her running!
Where did you find the block heater cord for the 603? my dealer can't find it.
I know it has a metal ring that screws onto the threaded cylinder after the cover is removed (near the block drain valve) and was offered as part of a factory offer to install the block heater (the one that was already installed from the factory!) The coupon is missing from my owner's manual (I doubt they honor them any longer anyhow)
I was planning to drive cross country but not this year, I'd like to have a heater cord when I do travel next winter.

Johnhef · #11 12-04-2005, 08:37 AM

that was the problem. we can't get the right cord that goes with the block heater that was already in the car so I used a similar one from another car that I had replaced the whole assembly on and "sealed" it to the heater plug in the block so it would work and not fall back out.

dieseldiehard · #12 12-04-2005, 01:50 PM

Quote:

Originally Posted by Johnhef

that was the problem. we can't get the right cord that goes with the block heater that was already in the car so I used a similar one from another car that I had replaced the whole assembly on and "sealed" it to the heater plug in the block so it would work and not fall back out.

ok, thanks for your advise
I thought of kluging something, using rtv and heat shrink tubing to affix it.
I wonder why factory cords aren't available?

whunter · #13 12-04-2005, 02:41 PM

Quote:

Originally Posted by dieseldiehard

The 603 starts much better than my 617 in cold weather. 17 degrees is the coldest I have experienced in my 300TD (617) it was a PITA to get her running!
Where did you find the block heater cord for the 603? my dealer can't find it.
I know it has a metal ring that screws onto the threaded cylinder after the cover is removed (near the block drain valve) and was offered as part of a factory offer to install the block heater (the one that was already installed from the factory!) The coupon is missing from my owner's manual (I doubt they honor them any longer anyhow)
I was planning to drive cross country but not this year, I'd like to have a heater cord when I do travel next winter.

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1987 Mercedes Benz 300D Turbo
Part: Block Heater Cord

Z6003-28873 Block Heater Cord United States IN STOCK
http://catalog.peachparts.com/item.wws?sku=Z6003-28873

Z6003-28873 Block Heater Cord IN STOCK
http://catalog.peachparts.com/item.wws?sku=Z6003-28873

SPECIAL ORDER: HEATER CORD FITS UP TO 01/96
http://catalog.peachparts.com/item.wws?sku=2015403134

SPECIAL ORDER: HEATER CORD FITS AS OF 02/96
http://catalog.peachparts.com/item.wws?sku=0001592932

Questions about Parts?
Call for help.

dieseldiehard · #14 12-04-2005, 03:07 PM

Quote:

Originally Posted by whunter

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1987 Mercedes Benz 300D Turbo
Part: Block Heater Cord

Z6003-28873 Block Heater Cord United States IN STOCK

Z6003-28873 Block Heater Cord IN STOCK

Well, I appreciate the info but that is not the right cord for the 603 engines. That is something of an aftermarket block heater that shows up all over the place for pre-603 engines.
I have one sitting in a box here too and assure you I would have used it if it fit the block heater on the 603, which uses a round plug that has a metal ring that screws onto the heater port, as described in my previous post
Thanks! DDH

whunter · #15 12-04-2005, 03:36 PM

Quote:

Originally Posted by dieseldiehard

Well, I appreciate the info but that is not the right cord for the 603 engines. That is something of an aftermarket block heater that shows up all over the place for pre-603 engines.
I have one sitting in a box here too and assure you I would have used it if it fit the block heater on the 603, which uses a round plug that has a metal ring that screws onto the heater port, as described in my previous post
Thanks! DDH

Did you call Phil?
I thought he got someone the correct one for a 603 last winter.
Working on my furnace or I would take more time and search this topic, as there is a thread from last winter where a member found the correct part number for a 603, can't recall if it was Phil or Rusty who found it.