Can extreme cold starts lead to engine symptoms? 1984 300D Turbo - PeachParts Mercedes-Benz Forum

Jack None · #1 01-09-2013, 02:03 PM

I just got back from a long trip (4k) through the cold. Now that I'm back I'm getting the following symptoms. None were apparent before the trip. It's around 45-60F here in LA.

Slightly rougher idle
Slightly harder cold starts (cranking a second longer than I'm used to, and maybe a sputter or two)
Some WHITE smoke for the first 10 seconds or so.

Here are some possible culprits. Yes, I should have had a plugin and proper oil, and I should not have used ether.

About half dozen starts in 10-20 degree F weather, without block heating and with 15W-40 oil. These starts required lots (maybe 8-12) cranking attempts, but the car finally started. After starting, there would be a bit of BLACK smoke, and these starts made black stains on the pavement under the exhaust. I was not happy to see this.
One start in 15-below F weather. I had to call a tow truck. We jumpered to the tow truck, and used two squirts (only) of ether. The ether may not have been necessary. When it finally did start, it had been a while since the ether had been applied. I did not hear or feel anything strange from the ether. The car ran fine for the rest of the trip.
Yes, I run on veg. I'd done around 15k on veg before this trip, with none of the symptoms I described. I purged carefully on the trip, and never ran veg below 80C. (Maybe even 90C.)
Less than 1000 miles before the trip, I did a valve adjustment. Maybe I messed it up? Or maybe I need to re-adjust, if e.g. it had been way too long since the previous adjustment?

What do the great minds here think?

I'll check compression soon, first I have to hit HF for the tester. I wish I had a before shot, but I don't. I also plan to check the valves. I can also check blow-by tonight. Before the trip, there was a little blow-by but it seemed not too bad for a 300k+ engine.

Yumeko-chan · #2 01-09-2013, 02:11 PM

If it'd been a long time since your previous valve adjustment, they usually recommend another adjustment 500 miles after your newest-previous one. I would try and adjust them again first.

Diesel911 · #3 01-09-2013, 02:29 PM

"I just got back from a long trip (4k) through the cold." The 4k puts you on the edge of Valve Adjustment time. Could it be that on the trip you Valves clearances tightened up? And, people say you should do that before the Compression Test.

White smoke is an indication of un-burned Atomized Fuel or a Coolant leak into the Cylinder/s.
Bad Injector (if the smoke puffs out) or late Fuel Injection pump timing could also account for the white smoke.
Look for evidence of a Head Gasket leak.

Since it is easy to do check the Glow Plugs.

You would think that extended cranking would only have a chance to damage the Starting System.

Jeremy5848 · #4 01-09-2013, 02:54 PM

The OM617 turbo engine is not normally bothered by cold weather or extended cranking. However, everything you describe (total miles on the car/engine, use of WVO, 15W40 oil, ~5K miles since valve adjust) is sub-optimal for cold weather operation. No serious damage has been done, IMHO.

You're due for a valve adjust and an oil change so do both and consider pulling the injectors for inspection, cleaning, and pop pressure adjustment; failing that do a diesel purge. In the future, a block heater and synthetic oil is recommended for cold-weather operation.

Jeremy

Zacharias · #5 01-09-2013, 03:08 PM

Having started and driven OM617s down to -32 F, I can pretty much assure you that cold weather doesn't have any aftereffects on these motors. In fact, the colder it is, the better mine have run.

Quote:

Yes, I run on veg. I'd done around 15k on veg before this trip, with none of the symptoms I described. I purged carefully on the trip, and never ran veg below 80C. (Maybe even 90C.)

The point isn't only how hot the motor temperature gauge indicates, that is half the equation with VO. What are you doing to preheat the VO prior to injection, and what injection temp are you achieving?

whunter · #6 01-09-2013, 03:16 PM

Quote:

Originally Posted by Jack None

I just got back from a long trip (4k) through the cold. Now that I'm back I'm getting the following symptoms. None were apparent before the trip. It's around 45-60F here in LA.

Slightly rougher idle
Slightly harder cold starts (cranking a second longer than I'm used to, and maybe a sputter or two)
Some WHITE smoke for the first 10 seconds or so.

Here are some possible culprits. Yes, I should have had a plugin and proper oil, and I should not have used ether.

About half dozen starts in 10-20 degree F weather, without block heating and with 15W-40 oil. These starts required lots (maybe 8-12) cranking attempts, but the car finally started. After starting, there would be a bit of BLACK smoke, and these starts made black stains on the pavement under the exhaust. I was not happy to see this.
One start in 15-below F weather. I had to call a tow truck. We jumpered to the tow truck, and used two squirts (only) of ether. The ether may not have been necessary. When it finally did start, it had been a while since the ether had been applied. I did not hear or feel anything strange from the ether. The car ran fine for the rest of the trip.
Yes, I run on veg. I'd done around 15k on veg before this trip, with none of the symptoms I described. I purged carefully on the trip, and never ran veg below 80C. (Maybe even 90C.)
Less than 1000 miles before the trip, I did a valve adjustment. Maybe I messed it up? Or maybe I need to re-adjust, if e.g. it had been way too long since the previous adjustment?

What do the great minds here think?

I'll check compression soon, first I have to hit HF for the tester. I wish I had a before shot, but I don't. I also plan to check the valves. I can also check blow-by tonight. Before the trip, there was a little blow-by but it seemed not too bad for a 300k+ engine.

Slightly harder cold starts = bad glow plugs, thick (wrong viscosity oil) (0 or 5W-40 synthetic is recommended), lousy fuel quality, valves out of adjustment.
You can also have a combination of these issues.

http://www.peachparts.com/shopforum/2246388-post7.html

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

http://www.peachparts.com/shopforum/diesel-discussion/107729-valve-adjustment-om615-616-617-fyi.html

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

http://www.peachparts.com/shopforum/diesel-discussion/309367-warning-all-diesel-owners.html#post2841158

http://www.peachparts.com/shopforum/diesel-discussion/205368-diesel-owners-need-know-fuel-data.html

Diesel fuel is prone to waxing or gelling in cold weather; both are terms for the solidification of diesel oil into a partially crystalline state.
http://en.wikipedia.org/wiki/Winter_diesel_fuel

.

kerry · #7 01-09-2013, 03:45 PM

Probably a weak glow plug.

Jack None · #8 01-09-2013, 05:45 PM

Lots of fun stuff to check. Thanks.

Quote:

Originally Posted by Zacharias

The point isn't only how hot the motor temperature gauge indicates, that is half the equation with VO. What are you doing to preheat the VO prior to injection, and what injection temp are you achieving?

The 20-plate FPHE gets too hot to touch. Not a lot of hose between FPHE and lift pump, and those bits are insulated. I don't have a separate fuel temp sensor. Car runs around 90-100C. I'm reasonably sure the veg fuel is good and hot (80C or more) at the injectors.

Murkybenz · #9 01-09-2013, 06:01 PM

Replace the fuel filters and see if any change

Diesel911 · #10 01-09-2013, 06:32 PM

Quote:

Originally Posted by Diesel911

"I just got back from a long trip (4k) through the cold." The 4k puts you on the edge of Valve Adjustment time. Could it be that on the trip you Valves clearances tightened up? And, people say you should do that before the Compression Test.

White smoke is an indication of un-burned Atomized Fuel or a Coolant leak into the Cylinder/s.
Bad Injector (if the smoke puffs out) or late Fuel Injection pump timing could also account for the white smoke.
Look for evidence of a Head Gasket leak.

Since it is easy to do check the Glow Plugs.

You would think that extended cranking would only have a chance to damage the Starting System.

The above stuff was for an Engine running on Diesel Fuel; I did not notice the two tank veg oil notation.

barry12345 · #11 01-09-2013, 08:23 PM

The colder intake air may have tended to reduce the total burn of the vegatable oil. May contribute to some ring gumming.

An outside possibility but what we used to refer as carb heating to reduce icing of the carb is not available on these diesels. Although I see no reason some form of it could not be engineered in. Diesel has a much faster flame front than vegatable oil. Any real lowering of the combustion chamber temperature is going to have some effect.

Zacharias · #12 01-09-2013, 08:28 PM

Quote:

Originally Posted by Jack None

The 20-plate FPHE gets too hot to touch. Not a lot of hose between FPHE and lift pump, and those bits are insulated. I don't have a separate fuel temp sensor. Car runs around 90-100C. I'm reasonably sure the veg fuel is good and hot (80C or more) at the injectors.

The reason I asked is that LA was probably the capital city for bad vegoil conversions a few years back. Lots of cars running around with little or no heat.

In any event, what works in LA won't necessarily be sufficient in harsher temps. If you plan to repeat this trip, I'd advise installing 12v heat wraps on your injector lines.