winter, glow pugs, radiator and other mysteries - PeachParts Mercedes-Benz Forum

monster hobby · #1 01-31-2007, 03:56 PM

greetings, i need some help diagonsing my 83 300sd @150k.

in warmer temperatures (the charlotte area of nc) the car fired right up with no problems. now in the colder Appalachians where temperature have been anywhere from 10-30 degrees F, the car takes nearly an hour to start. of course this is done with another car jumping it as the battery quickly wears down.

i have tested the ohms to the glowplugs as well as affirmed that the relay and wire were getting power to the glow plugs. all were receiing at least 11.40 ohms. nevertheless, the all symptyms lead me to believe that there is a glow plug problem. thoughts?

[i have ordered a 300watt magnetic block heater and i hope that this will ease many of my winter woes. I am also using anti gel diesel additive.
new battery, new air oil and fuel filters, new oil]

i also recieved a crack in the plastic top of the radiator and spewed all a my radiator fluid while running it. i have heard that this 2 1/2 inch crack can be filled with steel reinforced epoxy, however i wonder if there is something else wrong with the radiator that i should check into before patching adn refilling.

prior to this instance, my on dash temperature gauge read 120degrees thought the engine on touch was not nearly that hot. the gauge needle has been fluttering hinting at an electricle problem. it pulses at the same rate as the light on the stereo and other gauges and lights on the dash. perhaps my thermomitor of the raditor is stuck open or the cold weather is reaking havok on the old plastic radiator top.

reccommendations?

Biodiesel300TD · #2 01-31-2007, 04:16 PM

Quote:

Originally Posted by monster hobby

i have tested the ohms to the glowplugs as well as affirmed that the relay and wire were getting power to the glow plugs. all were receiing at least 11.40 ohms. nevertheless, the all symptyms lead me to believe that there is a glow plug problem. thoughts?

I think you are talking about measuring volts. You should be getting close to 12 volts to each plug. To test each glow plug you want to use the Ohm setting on your multi-meter. This measures the resistance. If any plugs show high resistance they are bad and they need to be replaced. I bet you have a bad GP or two.

winmutt · #3 01-31-2007, 04:29 PM

Also pull the instrument panel and look for burned circuits and check the grounds.

rrgrassi · #4 01-31-2007, 04:35 PM

I would replace the radiator. The plastic ends do get weak over time. The patch should be looked at as temporary.

sokoloff · #5 01-31-2007, 04:43 PM

Good glow plugs should read about 0.6 ohms cold.

Len

ned2683 · #6 02-01-2007, 12:12 AM

make sure u have the proper size battery too. PO had a dinky battery in mine when i changed it to the group 49 i noticed much much faster crank times and basically made my car startable down to 0F (so far this is the coldest i have had to start) where as before i strugged at 15F or so. faster crank=better compression (?)

monster hobby · #7 02-01-2007, 08:01 PM

got the glow plugs out and hooked them up to the battery.... at least two of the five are out.

i check the fuses and they were fine.
the battery is a 12V big guy. should be enough.

thanks.

as for the radiator, i think i need a new one. and suggestions on finding a cheap new one or a good used one?