Herblenny

Please help me...

I was approached by a good friend asking me about Mercedes.
I have no clue about diesel cars.

The problem is:

After he got his glow plug (I have no clue what that is) replaced 2 years ago. Every time he tries to start when weather is cooler (below 50F), its near impossible for him to start his car.

Wondering if anyone else experienced this kind of behavior at just a warm temp.

Anything above 50F the car starts fine and runs great!

I've read something about getting a heat block? but he is in Alabama and weather rarely gets below 30F..

Please post your thoughts.

thank you!

PHILIP SOHN

Steve Clark

First,are the valves properly adjusted?.Tight valves will bleed off cranking compression and result in hard starts.
If the valve clearances are OK, a compression test is in order.

While a block heater definitely helps, a healthy 80's MBZ diesel should start at 20 degrees F.
Procedure for a cold start is...
Preheat until glow plug light goes out,hold key in same position and wait 10-15 seconds more.(the glowplug light going out means that it's preheated,but the glowplugs are still on at this point.More is better in this situation.)
Floor throttle WFO and crank the engine.Keep the loud pedal on the floor and continue cranking until either the engine starts or the battery runs down.

sph17

In addition to the previous suggestions:

What weight motor oil is in the car? 20W-50 is great for the winter, but will cause problems when it gets cold. 10W-30 would be a good choice for Alabama winters.

When was the last time the fuel pre-filter and fuel filter were changed? Water and crud can accumulate in the filters, causing problems.

Diesel fuel gels when it gets cold. I don't remember when exactly, but I believe it is in the mid 40's. Up north they "winterize" the Diesel fuel during the winter. I don't believe down south they winterize the diesel fuel. If the temp gets too cold, with non-winterized diesel, you will have problems. There are "winterizer additives" sold at auto supply stores that can help prevent geling, or the diesel fuel can be cut with up to 50% kerosene. Other people add one gallon of gasoline to a full tank of diesel to prevent gelling, but some people on this board will argue strongly against this practice.