Cold Start Tips Needed! - PeachParts Mercedes-Benz Forum

warmblood58 · #1 01-14-2010, 12:37 AM

Damn, car almost did not start this morning in Vail -temp was 9 degrees. Glow system is perfect, battery was strong (this car always starts) and I had winter diesel fuel in tank. What I did not do was plug the block heater in the night before -no outlet available! So engine was cranked about ten -twelve times with no fire! Fortunately, a guy next to me allowed me to jump off his truck which helped but for a while, I was beginning to think that my always highly reliable OM617 was not going to start ('82 300SD)

So hey cold weather brothers, what are your cold start tricks when in dire straits?

okyoureabeast · #2 01-14-2010, 12:52 AM

What weight oil are you running and when were your valves adjusted?

How old is the battery and how fast did the starter sound like it was spinning?

warmblood58 · #3 01-14-2010, 01:07 AM

valves adjusted 3 months ago - oil is delo 15/40 and battery initially aqllowed for a pretty fast crank speed though synthetic would allow for faster cranking speed

Jeremy5848 · #4 01-14-2010, 01:11 AM

If you cannot run an extension cord to the car, consider removing the battery and taking it inside overnight. (A cold battery has only about half the capacity of a warm one.) Put the battery on a trickle charger. In the morning you will have a fully charged warm battery to put back into the car and it will be much more likely to start the engine.

warmblood58 · #5 01-14-2010, 01:13 AM

great tip Jeremy -next time I will put a spare battery in trunk which I will keep inside with me

soothappens · #6 01-14-2010, 01:13 AM

Check your battery. Mine will allow almost 1 - 2 minutes of cranking before needing a jump 850cca. I also have 15/40. Most parts stores will check it for free.

soothappens · #7 01-14-2010, 01:15 AM

Quote:

Originally Posted by soothappens

Check your battery. Mine will allow almost 1 - 2 minutes of cranking before needing a jump 850cca. I also have 15/40. Most parts stores will check it for free.

Jeremy types faster.

fruitcakesa · #8 01-14-2010, 08:05 AM

If your battery is good you can try multiple full glow cycles before starting.
The 82 240 needed 4 rounds of 3 glow cycles before it would reluctantly start in single digit weather. Of course had it been plugged in it woulkd have started immediately.
Turn up your idle speed also when cold starting.

Baer · #9 01-14-2010, 08:41 AM

Mine does not like the single digit temperatures either. I usually have to glow it 3-4 time before starting. Plugged in is a different story.

I have been contemplating an idea for an auxiliary deep cycle battery with disconnect, and a 1500w inverter on a timer, all in the trunk, so I could plug it in when there is no outlet available.

The disconnect would allow the battery to charge when running but separate the two when not running, similar to a boat's house battery bank. what do you think? (I know the purists would not approve, but it is a pain when it's real cold with no outlets)

tr1cky · #10 01-14-2010, 09:33 AM

Have you ruled out low compression as a culprit?

snookwhaler · #11 01-14-2010, 09:33 AM

Mine always lights off as if it is 90 degrees outside. Even down into the teens. But, I'm sure the single digits would be a different story.

Alot of guys that live up there swear by 5/40 syn. oil in the winter. This is what I run in the winter too. Also, are you following the owners manual procedure for really cold starts? IE: depressing the accel pedal to the floor once and then holding it to the floor while starting (after several glow cycles).

Graplr · #12 01-14-2010, 09:39 AM

Quote:

Originally Posted by soothappens

Check your battery. Mine will allow almost 1 - 2 minutes of cranking before needing a jump 850cca. I also have 15/40. Most parts stores will check it for free.

At what ambient air temperatures are you getting 1-2 minutes of cranking out of the battery? The OP stated his was in the single digits. If he left it in the car overnight he will get much less than 1-2 minutes cranking time, especially if he glows longer. In cold weather (cold to me is below 15F) I probably get 2 maybe 3 shots at starting it for maybe a total of 30 seconds of total time. If I glow multiple times it may only be one shot before the battery is drained too much to turn the starter fast enough.

To the OP-

Lighter weight oil will help the engine spin faster and thus start easier in these colder temps.
Also, how long do you glow for? The FSM states to run a full glow cycle to aid in cold starting. The light goes off but the relay stays on for a bit over 30 seconds, then try starting it. Some people even do double glows by turning the key back off and then glowing again after the relay clicks off one time.

At 9F you should be able to easily start a healthy engine. I have cold started mine in -5F. I think the lighter weight oil really helps.

rscurtis · #13 01-14-2010, 10:30 AM

I intentionally left my 300 outside last Saturday night just to make sure everything was OK. Next morning was 9 degrees. It started in about two revolutions with one glow cycle without touching the throttle. This was on a 6 year old battery, but with Amsoil 5/40 European car oil. Makes me wonder what its limit is- hope I never have to find out.

Graplr · #14 01-14-2010, 10:40 AM

Quote:

Originally Posted by rscurtis

I intentionally left my 300 outside last Saturday night just to make sure everything was OK. Next morning was 9 degrees. It started in about two revolutions with one glow cycle without touching the throttle. This was on a 6 year old battery, but with Amsoil 5/40 European car oil. Makes me wonder what its limit is- hope I never have to find out.

Mobetta has stated he started his 84 300TD in -22F in a cold spell we had last winter. He posted it in a thread somewhere on here. I couldn't get mine started that same day. I had it plugged in but later found out the cord was frayed and not working...

My coldest cold start is about -5F. I haven't tried anything colder as I like to plug it in or run the Webasto (except for the -20F try which didn't work for me).

Archdukeferd · #15 01-14-2010, 10:56 AM

+1 more mine starts right up in the cold as long as I've been driving it recently. If I let it sit it for a while it takes a second, even if its warm out

My 300D had been sitting for almost 20 days with no start and yesterday it finally got warm (35 degrees). Almost went first crank, sprang to life on the second try. Gotta love these cars.

I also love it because the PO thought she had a battery drain, I'd say that sitting several weeks in single digit temps then firing right up means the electrical system is okay!