#1. So my 82 300 TDT with 280,000 was starting to really need cranking to get it to start when cold (below 60F).
Note: Your car is a 300TD Turbo W123.193 model produced 1980-1985, the TDT is a W124.193 model made in 1986 - 1987.
Answer: This is a cold start issue, typically valves out of adjustment and/or bad glow plugs.
GLOW PLUGS:
FYI: Trying to OHM a heating element designed for high temperature operation at ambient temperature gives a deceptive reading.
A new glow plug reads 0.7 OHM.
Heating the air to a minimum starting temperature of 850°C is critical for diesel engine start-up.
FYI:
The most common (good quality) "NEW" glow plug failure is over torquing the 8 MM wire nut = damaging the electrode internally.
This is an ELECTRICAL connection = watch the wire, and STOP tightening when it begins to move.
All of this being said, I junk any glow plug reading 0.9 or higher.
For best reading:
* Disconnect the glow plug harness from the relay.
* Red OHM meter wire goes on the 8 MM wire nut threaded pole/terminal.
* Black OHM meter wire goes on the steel body of the glow plug.
All of my used glow plugs are tested:
# With the HOT electrode in the jaws of a vice.
# Battery/charger ground attached to the vice.
# Positive applied to the wire nut threaded pole/terminal for 15 seconds.
After you have tested one good glow plug, and personally seen how bright/hot it gets, there is no mistaking weak/bad ones.
Warning: While diagnosing the glow plug system, do NOT touch any part of a hot glow plug.
Glow plugs run 1000° - 1300°C = "2372° Fahrenheit" optimal temperature range.
Touching the glow plug wire nut can cause severe burns, especially if there is a fault causing it to overheat.
1982 300D Low Compression On #5 Cylinder
How do Glow Plugs work?
How do Glow Plugs work? | Ask Pete
Please read the following thread for further data.
Glow plugs link thread
VALVE ADJUSTMENT:
If the valve adjustment was neglected long enough, it may require several valve adjustments in the same day.
As the gap between rocker and camshaft reduces, the valve opens sooner + is held open longer.
If ignored long enough this allows uneven carbon deposits to form on the valve mating face and seat = preventing a good seal = compression loss.
The correct procedure is to:
#A.
Adjust the valves, reassemble.
#B.
Italian Tune-up.
#C. Check the valve adjustment, if needed repeat step #A. and #B until there are no tight valves = you are done..
There is nothing wrong with adjusting valves on a warm engine, a cold adjustment is NOT superior, it is simply another way of doing the same job.
Factory trained mechanics rarely performed a COLD adjustment, they used the hot specification..
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