Now that the weather has gotten cold the 240d refuses to start. Before I start throwing money into it, I want to make sure I have decent compression, since the engine does have some blow-by. Valves have been adjusted, I was just wondering since the car won't start, I will only be able to get a cold reading...will this give me the results I need or does it need to be done with the engine warm??

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1981 240D

People argue both ways. I personally belive that a cold compression test is more reveling than a warm test. The cold test will tell you what you compression is when you get in and try to start on a cold morning. Just about any warm diesel will start, however a cold diesel is a different beast. In your case you are troubleshooting cold start issues, so a cold compression test will tell you what you need to know.

Before you go to testing compression though, make sure all your glow plugs are good, the GP system is working properly, and the fuel filters and air filter are fresh. Also are you running any biodiesel or veggie oil? You could have gelling issues that will cause hard starting as well.

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I live in Illinois also & I couldn't start my 300D. Block heater was on but the battery was frozen. I am thinking about getting a battery blanket for the Benz. I have a battery blanket for my Jeep, which started & got me to work this morning.

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1980 300SD (Mr. Sparkles), 1976 450SEL, 1982 300D turbo, 1989 VW Cabriolet morphing into a td cabriolet , 1997 TDI Passat, 1996 piece of Jeep,1993 F150, 1990 F250 7.3L...i think that's it, for now.

Have you confirmed that all the glow plugs are working?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Well I got the car started...started a fire under the oil pan and hooked up the jump pack. Also, Put some Power Service diesel additive in the tank and filter. I replaced all the glow plugs back in the fall w/ some "good" used ones out of my parts car...I checked them and they are still working. I did not, however, ream the holes so maybe I should go ahead and get a new set and do it this time.
The car smokes alot when it first starts and until it gets warm. Sometimes it seems like it has a "miss" to the engine even after it is warm.
I am planning ordering a set of rebuilt injectors w/ Monark nozzles, but wanted to check compression before I drop the money.
I've read of alot of guys changing to synthetic in the winter but I I've got a rear main seal leaking and don't want to make it any worse...

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1981 240D

Shell Rotella synthetic did not make my engine leak but it certainly made it turn over quicker in cold weather. Reaming the holes in my 116 improved cold starts by around 10 degrees. I'd ohm out the plugs and confirm they are getting voltage. Do you have loop or pencil plugs?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

My worries are since it already leaks it will leak worse. Back in the fall I checked the glow plug circuit when I replaced them....I have the pencil plugs.

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1981 240D

Just completed the compression test w/ warm engine and I must admit I was pretty pleased...Results were:

#1- 380
#2- 350
#3- 360
#4- 380

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1981 240D

Those are good numbers.

So your cold start issue is probably something else. Just cause your "good" used GPs tested good a few months ago doesn't mean they are still good. GPs are the most common hard starting issue. I'd pull them and give 'em 12v and see if the glow bright orange or not.

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I've got 4 new glowplugs in mine (new as in less than a week old) and just put Rotella synthetic in. I got desperate after several days it wouldn't start last week.

It's sitting out there now with the following:

1) Lower radiator hose heater is plugged in and will stay plugged in all night.
2) I have a 250W heat light near the back of the engine resting on the transmission.
3) I have a 100W bulb (fear of melting things) resting on the steering box.

Between those three heaters, I have heat sources in a rough triangle around the engine. And then to make it all stick,

4) A fiberglass blanket that was made to insulate a hot water heater is tucked in across the entire engine bay. The hood is closed down to hold it in place.

The idea is that those electric heat sources will produce heat "near" the block and then the insulation blanket will make the heat sort of surround everything. I tested this setup last night but it only went down to 25 degrees and at 25, I know conclusively that the car would have started ANYWAY.

Tonight it's supposed to go down to 7 above. THAT is a temp that I *know* made it fail to start with 15W40 and no electric heat other than glow plugs. So... if it works in the morning, we know this is a useful means of heating the engine.

The car doesn't have a factory block heater and we lack the resources to properly install one even if we could get the plug out. Might do it after Christmas. I am 100% positive that I don't have a heater-but-no-cord; there's no heater.

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~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

For about $15 you can get a cheap hairdryer which makes a usable block heater substitute. Throw a blanket over the hood that covers the radiator to speed the process.

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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png

Winter Cold starting issues are 98%:

#1. Bad glow plugs
#2. Valves not adjusted
#3. Weak battery and/or starter
#4. Bad/Poor ground from body to engine
#5. Engine oil to thick for the ambient temperature/climate.

Winter Cold starting issues that are 2%:

* Plugged filters
* Diesel jelled = summer fuel, contaminated fuel and/or extreme cold ambient temperature.
* Bad o-rings and/or hoses leaking air in the fuel system when cold.


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

Starter health is important to your diesel!!!
http://www.peachparts.com/shopforum/diesel-discussion/107318-starter-health-important-your-diesel.html#post739798

Cold weather starting links
http://www.peachparts.com/shopforum/diesel-discussion/137674-cold-weather-starting-links.html#post1018529





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ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

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