OM602 No-Start - Page 2 - PeachParts Mercedes-Benz Forum

mannys9130 · #16 01-12-2016, 05:18 AM

Changes can occur, but if the engine block has been sitting and the air temp is stable, the block won't get colder or stay colder if nothing is done to it. The block is slower to catch up, but when both are equal they will stay like that and both will transfer energy to become equal.

babymog · #17 01-12-2016, 08:15 AM

I think we're being picky here, and out of context. We could also discuss adiabatic lapse rate, ram-air effect, friction, ... but we're not flying.

I believe that the original poster was talking about it being 48F out, and the car sitting out overnight where the lower overnight temp might have cooled the engine more than the current ambient temp.

... but does it matter? The car won't start, and it has fuel, so it probably needs more heat either from compression, warm intake air, or from the surfaces in the combustion chamber.

mannys9130 · #18 01-12-2016, 11:37 PM

I'd say a hair dryer in the intake helps a lot, and if the block heater can be plugged in and left for a few hours the engine should start in a bit with both of those things, even without glow plugs.

vstech · #19 01-13-2016, 05:01 AM

Quote:

Originally Posted by mannys9130

Changes can occur, but if the engine block has been sitting and the air temp is stable, the block won't get colder or stay colder if nothing is done to it. The block is slower to catch up, but when both are equal they will stay like that and both will transfer energy to become equal.

I don't think very many places on earth have stable air temp... Especially in winter seasons. Air temps warm up some during the day compared to overnight. A huge block of iron will gradually conform to the temp it has been exposed to. If it's a warming air, the block will be colder. If it's a cooling air, the block will be warmer.

What it FEELS like to our 98degree hands is irrelevant to its actual temp.

DieselPaul · #20 01-13-2016, 10:35 AM

Friday it is supposed to be back up to 40. It is 5 right now. We will try to move the car then.

I used the air dryer trick on my dads 240D, but I would think it might be a bit harder on a turbocharged car since you can't get the heat to the motor quite as easily. Maybe use it to heat the intake runners?

Thanks for the insights guys. We are going to do DV seals, glow plugs, and send the injectors off to greazzer when its apart so this spring it should be better than it already is!

DieselPaul · #21 01-13-2016, 10:35 AM

Quote:

Originally Posted by vstech

What it FEELS like to our 98degree hands is irrelevant to its actual temp.

I think Manny probably knows that, but I can't count how many people I have had to explain that "feels like" and "wind chill" are irrelevant to a lump of iron haha.

funola · #22 01-13-2016, 11:12 AM

Quote:

Originally Posted by DieselPaul

Friday it is supposed to be back up to 40. It is 5 right now. We will try to move the car then.

I used the air dryer trick on my dads 240D, but I would think it might be a bit harder on a turbocharged car since you can't get the heat to the motor quite as easily. Maybe use it to heat the intake runners?

Thanks for the insights guys. We are going to do DV seals, glow plugs, and send the injectors off to greazzer when its apart so this spring it should be better than it already is!

Heating the intake air is different than heating the block, which takes time because of its large mass. Heating the intake runner won't help. Just let the heat gun run while you crank, does not matter if it's a turbo or not, the hot air will get inducted into the combustion chamber.

babymog · #23 01-13-2016, 12:32 PM

... or with a 5mm allen wrench and 2minutes you can remove the crossover pipe and blow it directly into the plenum.