hi guys,have a e300d 1995.have a problem with the glow plug indicator light on dash.(does not light up on pre glow) and comes on after about 2 mins after the car is running and stays on for approx 2 mins car starts no problem even when cold. anybody else had this one?any advice would be appreciated.thanks

Start by taking an ohm meter to the glow plug harness terminal at the relay box. Good plugs should read 0.6 ohms cold.

Len

thanks len will test plugs but would this cause the glow plug lamp to go weird?

95 e300d 169,000.

I had the same trouble at about 120,000. Started fine. Glow plug light stayed on a while after it started. Ended up needing a new wiring harness. Old one was cracked and in pretty bad shape.

Check all electrical connections for looseness and corrosion. Also check your relay. Electrical gremlins, especially the intermittant ones are worst things to trace.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Same car, same problem. 120K.
Took in to a dealer and had all my glow plugs replaced. No more glow plug problem.

Wish I was that lucky. My plugs needed to be changed. They were stuck, then one broke in the head. Had to pull the head.

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thank's for that guys.will test the plugs.don't fancy taking the head off though.

1995 300D, 165K. Runs great. Starts fine. Yesterday, glow plug lamp illuminated after car running for 20 minutes, then went out after restart. Turning on cold, no lamp. Turning off, then on again, glow lamp lights. Typcially, this would indicate one glow plug failed. (Off/on sequence twice with no lamp = more than one failed plug.) But...all plugs replaced in July, engine wiring harness replaced in August.

Where exactly is the relay and which terminal do I test. I actually think I've found the relay (in black box, 3"x3"x1", on driver's side front wheel well) and it does click when you turn the key. Seems OK. So now it's down to testing the plugs via the harness leads. Is there a a picture or guide anyplace?

Thanks-
Dave

Black box over driveside well is the directional. I'm looking for the relay for glow plugs too.
1984 300D

On the 84 300D, the relay is on the left fender well, near the front (behind the driver's side headlight. It's a black box about 1-1/2 x 1-1/2 x 3 inches. The cover snaps off and you can see a strip fuse about 1-inch long.

The direction light relay is in the center console, inside the car.

Once you find the relay box which ought to be on the driver's side fender, unplug the glow plug harness. Stick one lead from the ohm meter into one of the terminals. Ground the other. Read the results. Repeat. If you've got really good eyes, you can see the number for each glow plug on the harness connection and tell which plug is bad.

Len

...which is to be expected since I had an ohmmeter in one hand. Everyone was on their best behavior, including the glow plug lamp which is again working perfectly.

Cold (air temp 65 deg F) the number 5 plug looked a bit higher than the others (1 ohm+/- versus 0.5+/- for 1-4; my ohmmeter is an older, inexpensive analog type...

After the car came up to operating temp (engine +/- 80 deg C) I rechecked. All 5 plugs at 0.5 +/- ohms. I cleaned all contacts (looked spotless and tight to begin with...) and lamp is fine. We'll see...

FYI, from the top left corner of the connector (leads exiting at base) the connectors increment row-by-row (think F1 starting grid) -- row 1 is #1, #2, left to right, row 2 is #3, #4, and row 3 is #5, #6 (#6 is empty on my car...)

Thanks for the tips--made this check a breeze.

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Dave Evans
Austin, TX
1995 E300D
B50 Biodiesel = 56 MPG

what ever you do don'y try this yourself. I had two break off on me and i have the same car. first time I tried to drill it out, what a mistake. I drilled inot the head instead I got a engine out of a wreck it was cheaper than a new head. the second time 20,000 miles later one broke again and the head had to come off to drill it out. the head is almost impossible to get for this motor. let a mechanic do it. I would run a diesel purge first to loosen the carbon buildup on the end of the plug. just be careful

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Trying to keep Jersey Fresh

1995 E300D 384,000,(Betty White) part time greaser, lots of new parts
2004 Ranger XLT
2000 Chocolate Lab-Bad Quarter Panel, lots of miles