Winter starting victory! - PeachParts Mercedes-Benz Forum

xdjio · #1 12-21-2008, 07:14 PM

I just wanted to pass along to you guys my recent victory with cold starting. I replaced my plugs, reamed out the bores, and then also:

1) Adjusted my idle adjustment bolt
2) Replaced my fuel filters

And just last night I had the occasion to start the car at about -15C. It turned over happily after 2 cranks and idled stably right at 750, and stayed that way. I let it warm up just a little and drove home (safely and slowly). No issues at all! This was with 15W40 Liquimoly dino oil too. I am pretty impressed with the old gal!

zu! · #2 12-21-2008, 08:37 PM

I know what you mean about the cold temps!! Did you use the FSM method of flooring the pedal and then starting? That's what I've been doing these past few days. The only thing that scrares me about these cold starts is that with the pedal to the metal, when the car starts, its revving immediately to about 3000 rpm...not good, IMO, for a car with a stone cold engine!

Just curious though, what has the idle adjusment bolt have to do with cold starts? I would think a valve-adjustment would have more of an impact right?

xdjio · #3 12-21-2008, 10:50 PM

I have been pushing the pedal to the floor before I start, but otherwise I do not touch the pedal at all. It seems to help but maybe this is the placebo effect.

As far as the idle adjustment screw on the IP - I was having a touch time keeping a constant, steady 750 idle even in warm temps (it was more like 550 or 500) so I figured that being able to hold a steady idle at the right speed would help me all year long, not just in winters.

I do need to do the valves, but just gotta find time to do it (and some feeler gauges and read over the FSM a few times first).

It's getting to be around the time to change my oil too, so I am strongly considering switching to a fully synthetic 5W40. What are you running in yours?

zu! · #4 12-22-2008, 11:25 AM

So you start that way as well! Don't you keep it at that rev (pedal to the floor) for awhile? If I don't do it, it feels like the engine is about to die. And boy is it ever loud when you do it!

My idle is at about 850 or 900, at least that's how it looks on the tach. I noticed too that it kinda revs itself when very cold...kinda like a pulsing thing that doesn't register on the tach. Dunno what that's all about, but that stops after the engine is warm or after I've revved it to above 3000 rpms.

I think the valves are the most important thing to do here...according to all I've read, they're supposed to be done quite regularly. And if they're anything like an air-cooled vw, the difference in performance can be huge once done. I have the feeler gauges, just need to get the fancy wrenches

The other thing too is to probably wait until the cold weather subsides. The engine could probably do with a good pressure washing before opening up the valve cover and that won't happen in these sub-zero temps

Right now I'm running regular Shell Rotella 15-40. Everyone says that synth is better especially for cold starts, so you could try that out. I'm not due for an oil change yet. I've heard that it leaks a little more with lighter weight oil...

xdjio · #5 12-22-2008, 12:07 PM

I will lightly feather the accelerator if it seems like the motor is about to die but I have only ever needed to do that for about 5 or 10 seconds at most. When I do it, I try to just keep the RPMs around 1000 or so. Seems to work fairly well.

I had that odd pulsating idle feeling too - before I adjusted the idle speed. For me it also only ever happened when the engine was cold.

I do absolutely know my valves are overdue. It'll be a good spring or summer project to get the, back into shape though!

pawoSD · #6 12-22-2008, 12:54 PM

Thats extremely bad for the motor to rev it up like that when cold.

Yikes. My 617 starts and runs at 0F without even pressing the pedal at all. Sometimes I'll raise the idle to 900-1000 or so to help it warm up a bit faster, but I'd never rev it like that.

retmil46 · #7 12-22-2008, 02:31 PM

Guys, if you want to take the guess work out of cold weather starting, spend $12 and buy a digital voltmeter that plugs into the cigar lighter. After a couple tries, you'll see what voltage corresponds to nice hot glow plugs and drama-free startups. Also handy for spotting bad glow plugs, bad battery, and alternator problems.

On my wrecked '87, initially the plugs would pull down to 10.9 volts. Once the voltage was back up to 11.6, I knew things were warm enough to crank it over. If it didn't make it to 11.6 initially and timed out, I simply started a second cycle.

zu! · #8 12-22-2008, 03:24 PM

Quote:

Originally Posted by pawoSD

Thats extremely bad for the motor to rev it up like that when cold.

Yikes. My 617 starts and runs at 0F without even pressing the pedal at all. Sometimes I'll raise the idle to 900-1000 or so to help it warm up a bit faster, but I'd never rev it like that.

I agree! Problem is, when starting using the prescribed FSM method, that's what I'll get.

Seems to me like the best way to wear your engine down. However, using that starting method, I'm guaranteed of a good start. If I miss the first start, I'm pretty much toast for a 2nd start. Maybe the battery is weak...

curtludwig · #9 12-22-2008, 04:40 PM

You rev up some but don't hold it at 3000 rpm... How much wear could there actually be?

Lighter synthetic oil can sometimes seem like its causing leaks but in many cases will actually fix some minor leaks because of the seal softening properties of the oil. If you're going synthetic don't cheap out get a REAL synthetic like Mobil 1, Amsoil or Redline. I use Mobil 1 5w40 in my 190D which starts cold like a champ. When I first switched over oil consumption (leakage+burning) went up slightly (a quart in oh 1000 miles at worst) but has slowly declined (a qt in 3000 miles or so) to a point I'm quite satisfied with.

As a test put a quart of 15w40 conventional oil and 15w50 Mobil 1 in the freezer for a few hours and then try to pour each. The 15w40 will be like honey, real thick and sluggish, the M1 15w50 will pour like oil... The difference with M1 5w40 is even more dramatic and 0w40 is more dramatic still.
Both of my cars made a lot more klatta klatta with 0w40 so I use 5w40. I can see no particular difference between 5w40 and 15w50. Mercedes rates the 5w40 higher and its slightly cheaper because the only 15w50 I can find is the EP (Extended performance) variety so I use 5w40.