96 300d... how cold is too cold?
 

Welp... after much ado getting new glow plugs installed in my 96 E300D, I figured it was ready for anything. Drove it to work yesterday... started just fine (block heater plugged in), then when my wife went to use the car at lunch, she had a heck of a time starting it (temp in the mid teens) and got a battery charge warning. She finally got it started, drove it a few miles, then parked it at work again. When 4 pm rolled around, the car started just fine.

Today, we went into town (started just fine again) and the car sat until 4 pm again. I was the one to try to start it this time... NO GO! Cranked--rested--cranked--rested for several minutes... got the battery charge light, so flagged down a jump start (mid teens again BTW.) After several attempts, the beast finally started. Not good for the battery, I suspect!!!

I was worried that I had a frozen fuel line or something, but once it started, it ran just fine.

'leads to the BIG QUESTION: How cold is too cold to drive this car if it's not plugged in? It seemed to do fine when the temp was above 30F... but getting stranded when it weather is in the mid teens is not my idea of a good time.

At what temp should I consider driving a gas burner?

Thanks in advance!

-l-

How old is your battery? Have you had it tested? Perhaps your alternator isn't charging the battery properly? Unless you're running SVO or biodiesel, these should start in very low temps (assuming decent engine compression) I have an 83 300D with only 4 out of 5 working glow plugs and I have never had an issue starting it in even the coldest Michigan weather ( Yes, it misses for a bit)

How old are the injectors?

I have a 1999 E300. It starts as well in the low teens and the thirties.

I just started my diesel in 2 degree weather yesterday. Something must be wrong with your car such as glow plugs. Also i did not have the block heater on.

Also, fuel quality can make a big difference.
Filters?

Hi , I have a 240 d with about 260k on the odo. This morning when I first started my car it was 9F outside. My car is parked outdoors, not pluged in. I bought the car last year in Texas, about this time of the year and imidiatly had starting problems when the weather dipped into the teens. (I live in Kansas) A simple oil change to mobil 1 5W20 made starting much easyer. Also check your battery, Is it the proper battery, and in good condition? Also, starters will loose torque with old age. nothing a good rebuilding wont cure. Just because the starter turns the motor dosent meen that it is fast enough.
So number one, Change oil to a low viscosity oil , two if your battery is old get a new one, also check your charging system to make sure it is preforming properly. (the battery place can do this)If these items are in good order thats the most common problems.
I have rebuilt my starter and the car turns over faster now, but for me it was the oil and battery that did the trick.
Jon J
1981 240D
260K

Have you considered adding a small amount of petrol to the tank (say 5% or less) to reduce any gelling?

I would try several, make that dozens of other options before I added gasoline to the fuel in that car. Winterized diesel should not be gelling at that temperature.

For a point of reference, my 1996 E300D has been starting fine in the negative single digits we have had in Chicago for the past few weeks.

I have a '95 E300D and haven't had any troubles with cold starts. The other day it was about 10* outside and it fired right up after one glow of the plugs. When it gets real cold I will often glow the plugs twice just for kicks, probably don't need to, but I figure it can't really hurt anything.

The first thing you should do is check tha battery. If your battery is even borderline, temps that cold can suck the life out of it. And if the battery gets drained and freezes, then situation gets even worse. If you can, take the car to one of the many parts chain stores and have them test the battery and alternator. If that checks out okay, then check your plugs.

I am really loving my block heater this winter, but not for getting the car stated - rather, just for getting it warm so I can take off down the road quicker. Good luck.

ditto on checking the battery.

this morning we started right up at -8°F (outside, not plugged in).

...and the original question is a trick one - at no temperature should you consider trading it for a gasser.

I'd look for air in a fuel line. Was it parked nose up in town perchance?

Terry, as usual, has a good point. I changed out my prefilter a couple of months ago and the new o-rings that came with it was not sealing it up properly. Took it for a drive down the road, stopped somewhere, got back in a few minutes later and nothing - wouldn't turn over. On top of that, I subsequently killed the battery (which must have been on it's way out) trying to get started. Double bummer! One new o-ring and one new battery later and everyone was happy again.

Whew... I'll try to answer all the comments so far (THANK YOU!!!)...

First, I don't know how old the battery is. It is was with the car when I purchased it in Houston this summer. I guess what I don't understand (with regards to the battery) is... if it cranked (and cranked... and cranked) shouldn't that allude to the battery being OK? The car cranks... sometimes sputters, then cranks (no sputter.) It is not as if the car only cranked 3 or 4 times then the battery charge light came on. Am I missing something? Also, I should note I just changed all glow plugs last week, so I'm hoping that is not the issue (again!)

As far as fuel goes, I been adding the Powerstop additive to prevent gelling. I'm thinking that if gelling were the issue, it wouldn't have started at all, regardless as to the amount of cranking.

Oil is Rotella synthetic (5w-40 is the weight or is it 5w-30?)

As for the parking of the car in town. It is at a slight incline (perhaps 2 degrees.)

Once the car was started, it ran perfectly...

Dunno...

THanks!

-l-

Oops... forgot to mention... don't know the age of injectors... I'm assuming the same age of the car. Also, I was told (by the prior owner) that the fuel filter had just been changed (that would have been at 134K.) Don't know if this car has a pre-filter... I do have a new main filter on the shelf though.

-l-