300TD Glow Plug Issue - Help!
12-07-2011, 04:19 PM
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1985 300TD Wagon
300TD Glow Plug Issue - Help!
Hey Gents,
I own a 1985 300TD with 200K miles on it. About two months ago my glow plug light stopped illuminating when electrical power was applied. I know it wasn't just the lamp because the engine would have to crank several times before it started to catch. I'm guessing just the friction within the engine is what's warming things up. Now that the weather is starting to get much colder, the thing can barely crank. Could it be a connection issue with the ignition sequence to the glow plugs or do you think my glow plugs need to be replaced altogether? What do I need to do to alleviate this problem? My local mechanic has no idea what the issue is and is of no help to me. Maybe I should take this to a diesel engine specialist.
This is a little troubling considering my "*******" wagon is my primary mode of transportation.
Any help or direction would be greatly appreciated. Thanks!
I own a 1985 300TD with 200K miles on it. About two months ago my glow plug light stopped illuminating when electrical power was applied. I know it wasn't just the lamp because the engine would have to crank several times before it started to catch. I'm guessing just the friction within the engine is what's warming things up. Now that the weather is starting to get much colder, the thing can barely crank. Could it be a connection issue with the ignition sequence to the glow plugs or do you think my glow plugs need to be replaced altogether? What do I need to do to alleviate this problem? My local mechanic has no idea what the issue is and is of no help to me. Maybe I should take this to a diesel engine specialist.
This is a little troubling considering my "*******" wagon is my primary mode of transportation.
Any help or direction would be greatly appreciated. Thanks!
12-07-2011, 06:58 PM
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things with and without wheels
Take a look at this, it might help https://mbworld.org/forums/diesel-fo...ngine-now.html
Last edited by RobertG; 12-07-2011 at 07:12 PM.
12-29-2011, 12:37 AM
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83, 300D Federal
Old thread but for others:
Remove the Plastic Cover from the Glow Plug Relay and inspect the metal Strip Fuse. See if it is burnt or cracked; also check for loose screws.
If the above is OK go to the Diesel Giant Website and see how to check the Glow Plugs with a Multimeter (Volt/Ohm Meter). (This is not a recommend to buy parts there as my personal thought is He chargers too much.)
If the Plugs seem OK from the above test you need to check the Glow Plug Relay to see if it is working. When you turn the Key to the Preglow Position you should hear a click or thunk. If you keep the Key in the preglow positon the Relay can stay on for about 30 seconds (even though the Glow Plug Light goes off sooner) before the timer shuts it off.
(This means that on cold days you can keep the Key in the preglow positon and Glow for the full 30 seconds and even cycle the key again and Glow again; if your Battery can take it.)
Some people claim that if you leave the Door open your interior Dome Light will dim during the time the Glow Plug Relay is on and the light will get brighter when the Relay goes off.
If the Relay appears to be working and you are still having an issue with the Plugs not working; remove all the Glow Plugs and use a Jumper Cable and test them on your Car Battery.
Good Plugs start getting Hot at the Tip and remain hottest at the Tip. Plugs that get hot first anyplace else but the tip and remain hotter anyplace else but the tip are no good.
While the Glow Plugs are out Ream (there is a Glow Plug Reamer, tool for that) or otherwise clean the Carbon out of the Glow Plug Holes. This allows your Glow Plugs to last longer and Engine to start easier.
Use only Bosch or Beru Glow Plugs and other donot hold up. Avoide Autolite Glow Plugs entirely as the tips swell up on them and you may not get them out.
Berus are better Plugs but cost more and are harder to find. Bosch Plugs are entirely adequate, cost less and easier to find.
Remove the Plastic Cover from the Glow Plug Relay and inspect the metal Strip Fuse. See if it is burnt or cracked; also check for loose screws.
If the above is OK go to the Diesel Giant Website and see how to check the Glow Plugs with a Multimeter (Volt/Ohm Meter). (This is not a recommend to buy parts there as my personal thought is He chargers too much.)
If the Plugs seem OK from the above test you need to check the Glow Plug Relay to see if it is working. When you turn the Key to the Preglow Position you should hear a click or thunk. If you keep the Key in the preglow positon the Relay can stay on for about 30 seconds (even though the Glow Plug Light goes off sooner) before the timer shuts it off.
(This means that on cold days you can keep the Key in the preglow positon and Glow for the full 30 seconds and even cycle the key again and Glow again; if your Battery can take it.)
Some people claim that if you leave the Door open your interior Dome Light will dim during the time the Glow Plug Relay is on and the light will get brighter when the Relay goes off.
If the Relay appears to be working and you are still having an issue with the Plugs not working; remove all the Glow Plugs and use a Jumper Cable and test them on your Car Battery.
Good Plugs start getting Hot at the Tip and remain hottest at the Tip. Plugs that get hot first anyplace else but the tip and remain hotter anyplace else but the tip are no good.
While the Glow Plugs are out Ream (there is a Glow Plug Reamer, tool for that) or otherwise clean the Carbon out of the Glow Plug Holes. This allows your Glow Plugs to last longer and Engine to start easier.
Use only Bosch or Beru Glow Plugs and other donot hold up. Avoide Autolite Glow Plugs entirely as the tips swell up on them and you may not get them out.
Berus are better Plugs but cost more and are harder to find. Bosch Plugs are entirely adequate, cost less and easier to find.
