My '77 240D starts hard in colder weather. I've switched from B50 biodiesel, now using regular diesel (actually B5 around here) which helped for awhile. I have a block heater but the car is parked across the street and can't plug in at the moment.

It is not THAT cold here... 45°F this morning after a low of about 39° last night. I give it 3 GP cycles but no luck.

Would it be OK to pour boiling hot water on the block just to warm things up? I'd just like to get the thing started so that I can get it in to a mechanic to check the plugs, etc.

Cheers and TIA.

Have the valves been adjusted recently? All the glow plugs are working?

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1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

39 degrees shouldn't be cold enough for b5 to cloud or gel. Check your glowplug system.

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1982 240 D, 308,000 - 321,127 miles (sold)
1982 300 TD,166,500 - 226,000 miles
1998 E 320, 120,000 - 144,000 miles
2005 C 230 K, 26,000 - 77,000 miles (sold)

I second the valve adjust. Also, what grade of oil are you running? 5W40 or 0W40 will make cranking considerably easier in cold weather than 15W40. What kind of shape is your battery in? Weak batteries+cold=no go. Does your car still have the original loop style plugs? If so, one bad one will stop the whole system from working.

My car has loop plugs and is about 100,000 miles past due for injectors, but it will still start in temperatures considerably below freezing without plugging in.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Here is what I do with my 84 300TD to maximize ability to start in cold weather....

1. I change glow plugs every three years...I find that after about 3 years, they do not heat up as hot (this may be a figment of my imagination).

2. Every fall, I remove the glow plugs and ream out the carbon that builds up around the glow plug element..I have the little reamer tool that does this. Carbon buildup will act as a heat sink which will prevent the tips of the glow plugs from reaching maximum heat. (I don't know if your car has the old loop style glow plugs, or the pencil type, but the principals still apply). Before I reinstall them, I sand the electrical connectors with fine sand paper to ensure good electrical contact.

3. In the winter, I use Rotella 5-40 synthetic, because it is less viscous when cold (5w) than regular dino oil (15, 40W)...easier to crank.

4. I adjust valve clearances a few times per year, including just before the cold weather in late fall in preparation for winter...you want to make sure valves seat properly to maximize compression.

5. Make sure your battery is in good shape...if the battery is old and tired, you will find it tough to start in the winter, because sometimes you need to crank the starter for several seconds after several glow plug cycles, and a marginal battery just won't do this. My battery was not being charged well....this is a long story related to my stereo amps and other factors, but in the end, I concluded that the stock 65 amp alternater was not sufficient for my needs, so I got a drop-in 120 amp replacement alternator from Eagle Auto Electronics...I am very happy with it. My volt meter always sits at 14 v no matter what electronics are on. This ensures that each morning I will have plenty of cranking power to start the car. Also remember, it is important that you can crank the starter as fast as possible, not just for a long duration... Fast RPMs means that the cranking will deliver a higher "compression punch" needed to start the car. A sluggish battery may be able to crank the engine for several seconds, but just not fast enough to deliver a good punch.

6. For the same reasons discussed in # 5 above, I installed larger battery leads and ground strap...I made battery leads from 1/0 welding cable, and I made a 1/0 ground strap out of bare copper wire from Home Depot...(I cut about 75 lengths of this wire...sorted in bundles, twisted each bundle, then twisted the bundles together and soldered them into two 1/0 copper lugs).

7. For the same reasons above, clean battery terminals...all of these factors ensures fast and long cranking power.

8. Injectors....installing newly rebuild injectors that have been set to the correct pop pressures, and have been tested for good spray pattern is important for starting...a nice fine injector fuel spray will start (and run) better than an injector that squirts a stream of fuel. A good injector spray pattern is especially important for older diesels that may have less than optimum compression. Run a can of diesel purge every year to clean injectors.

9. All of the above factors are to maximize the ability to start the car in very cold weather, when I can't plug in the block heater. Most nights I do plug in the block heater at home in my driveway, and the car will always start regardless of the above factors. I also made a battery booster from a sealed lead acid batter I bought from Rage Battery, or you can just buy a good one off the shelf. When I travel up north in the winter and must park the car where I cant plug it in (hotel), I bring the booster battery indoors with me and either charge it just keep it warm. In the morning, if the temp. is 10degF or lower, I attach the booster battery to the battery leads before I even try to start the car. Then I will give it 5 to 10 glow plug cycles, to warm the pre chambers as much as possible. Then I crank the starter and hold it till she catches...you must be carefull though, because you really dont want to crank the starter for too too long...but in really cold weather, I may need to crank the engine for 10 to 15 seconds and no more.

10. Have a good set of jumper cables...I made a set...20 feet long, out of 1 gauge welding cable. It is good to have the long cables in case you are parked in such a way that another car can't pull up along side. And these cables need to be large gauge copper, otherwise the starter can't draw sufficient current to crank fast.

11. Change fuel filters every year...this is not for cold starts..just a winterizing measure....minimizes the chance that gelled fuel will block filters.

Good luck,

Mark

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

How long do you let the glow plugs glow? It was 44 degrees here a coupel weeks ago, i let the glow plugs glow for 20 sec( i have the old loop plugs) and held the throttle 1/2 open( owners manual says to do so in colder weather) and it fired right up with only 2 turns of the motor.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

I let my glow plugs glow for the full cycle....not just when the light goes out, but when the glow plug relay clicks off...about 40 seconds or so? I have a volt meter installed, so when I see it jump up when the glow plugs stop drawing current, I know the cycle is over.

Down to about 15 degF, the car starts readily on one or two glow plug cycles...below that, it is progressively more of a challenge. At about 5 deg.F and lower, I hook up my booster battery, do about ten full glow plug cycles, then go for it, running the starter for 10 to 15 seconds until it catches. At ten below, I also keep my fingers crossed and hope for a divine power to start the car.

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

I wouldn't consider those temperatures to be cold weather. If you're having trouble starting it at those temperatures something is wrong. Could be either compression or glow plugs. I'd begin by checking the glowplugs, then run a compression test.

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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

Why take it to a mechanic? We have all the help you need right here to fix it. Most of the responses are accurate...first you need to make sure your glow plugs are actually working and second, if they are, you need to check compression or do a valve adjustment if one hasn't been done in the past 15K miles or so. If your car won't start in 45 degrees you either aren't getting glow or the compression is bad, period.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

+1

The mechanic could do the valve adj if you don't want to, but if you just take it in and say it won't start, you may be buying lots of new parts and paying them to put them in! (some mechanics are honest, about the same % as other people)

Mine started today at 38 degrees, just waited till the light went out, and cranked for 2-3 sec . . .

Pull your glow plugs and put 12v to them, it easy! You can do it!

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82 240D Manual 277K and still rolling!
02 Volvo S60 AWD For Sale

Keeping the battery on a trickle charger overnight keeps the battery at peak and also warms it a little. If you cannot park the car where power is available you could try removing the battery on cold nights and keep it inside on a trickle charger. Then you'll have a fresh warm battery in the morning.

However, based on the quoted temps and the other comments, there is some other problem here. Your car should start easily. Glow plugs and valve adjustment would be my first two picks, echoing previous posters.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Thanks for sharing the cold start tips.

Get an oil change so the gunk is out of the engine and will result in quicker engine starts. The quicker the engine starts the less wear on the battery. Always keep your gas tank full.

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Service Consulting

BINGO !!!!!!!

Here we have a man actually following the instructions given from Mercedes Benz. This made all the difference on starting my wagon. Read what he said carefully... .there IS a difference in doing what he described and just turning your key on repeatedly.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I agree with the others, it shouldn't have problems at 45F. The most Likely causes are glow plugs and valve adjustment. Also, worn injectors can lead to hard starting.

For cold weather (below 10 or 15F) I have my block heater, battery heater, and trickle charger all wired to the plug on my car so they all work when I plug it in.

I was having slow starts and longer crank times when trying to start just after the GP light went out, so I began waiting for the relay to click before starting. Now it usually fires after 2 cranks.

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily