Is there a relay that needs replacing?

⟐ Commented August 16, 2025 at 4:27 MST

I just bought a restored Euro spec 1983 Mercedes 300D W123 that was running beautifully until last week, when I filled it up with Propel Diesel HPR, a renewable diesel that is supposed to be compatible with all diesel engines (and is marked as Diesel #2 that meets ASTM D975 specifications: http://www.dieselhpr.com/ ). Then I drove for four hours to Las Vegas from Los Angeles without any issues. It ran well for that evening after driving to a restaurant, parking, then starting again and back the hotel, where I had to park it outside on a cold and rainy night overnight with about a quarter tank left.

The next morning, I had a crazy cold start and the engine was shaking and wobbling a lot, along with the car as a result, even while I was driving slowly and definitely at idle. It eventually evened out, or so I thought. I figured it might be the Diesel HPR, so I filled it up later that day with regular Diesel #2 but the issues didn't go away the four days I was there.

I drove back to LA four days later, experiencing no issues on the highway, where it sounded and ran well. I ran the tank down until the fuel indicator went on, and then, in an effort to rule out Diesel HPR as the culprit (since it's supposed to be better for the environment), I filled it up with Diesel HPR again, thinking maybe it was just the cold in Las Vegas that caused the issues.

This week in LA, the temperature hasn't been as cold at night, even though I park it in a garage, and the issue seems to be worse. The wobbling isn't so bad once I get going, but it's there at the start and sometimes when I stop for a light. Meanwhile, the clicking sound is pretty constant, and sounds as though it's coming from the bottom of the car, though it sometimes quiets down at higher speeds and randomly at some lights. Since it was literally conking out during the cold start once I started reversing or driving slowly, I am now cold starting with the ignition lever turned up, and that hasn't really made much of a difference (just makes the clicking sound faster). Also, white smoke comes out of the exhaust during this initial starting period, and a few minutes after getting on the road, though it seems to disappear later. I've been waiting for the glow plug lights to go off, as indicated in the manual. (Weirdly, the glow plug light went on again a couple of times after the car started during the rough cold start/idle.)

At any rate, at this point, I'm not even sure if it's the Diesel HPR or something else (the cold, driving to LV) that created the issue, but am wondering if anyone has any ideas as to what the issue could be. Or does anyone have any experience with Diesel HPR and older diesel engines? I'm hoping this is an easy fix, since I just bought the car.

I'm going to take it in to get looked at, but am wondering if this is serious and urgent or if I should try it one more time with regular diesel to see if that clears up the issue. I definitely don't want to make the car worse if driving it more to troubleshoot does that.

In a perfect world, I'd like to be able to use Diesel HPR as it is better for the environment, so I'm wondering if it is even the culprit here. Thanks in advance for any advice or insight.

Tom

⟐ Answered July 26, 2025 at 17:51 MST

Thanks a lot!

Theo

thank you.

⟐ Commented June 18, 2025 at 18:15 MST

⟐ Commented March 22, 2025 at 6:39 MST

⟐ Answered December 21, 2024 at 20:46 MST

⟐ Commented October 24, 2024 at 21:55 MST

head and fog lights do not turn on

have replaced all fuses, checked ground on passenger headlight corner

passing light lever on turn signal will make headlights work therefor its not the bulbs

rear defrost out

cruise control out

tachometer works, speedometer works, turn signals work , rear lights work, hazard lights work.

no loose wires apparent

help please

⟐ Answered October 22, 2024 at 19:42 MST

⟐ Commented June 27, 2024 at 1:17 MST

⟐ Commented June 12, 2024 at 7:06 MST

Clutch cylinder replacement guide

I have an oil leak when driving from the base of the distributor I changed the o ring last year but have been told the shaft doesn’t actually need an o ring

Any ideas of clarification

link to picture of where it’s leaking the shaft and Bosch diagram

https://freeimage.host/i/XNzwns

https://freeimage.host/i/XNEla9

https://freeimage.host/i/XNE0ve

Thanks in advance

Update : looks like it’s leaking from the distributor shaft housing

Looks like there is an o ring there, didn’t know housing had an o ring? also I tried to undo the bolt but couldn’t crack it open is it ok to give it a strongman torque on it?

https://freeimage.host/i/XOFXzx

⟐ Commented October 23, 2023 at 5:06 MST

⟐ Answer edited April 23, 2023 at 21:13 MST

this vehicule is equiped with LPG installation, maybe it can help .

Other issues are the wheels are stuck and the trunk won't open.

thanks for answering !

⟐ Commented April 01, 2023 at 16:54 MST

Anyway I have sunk lots of time and cash into every part of this car as I get it ready for paint, my only issue is is that this car is all stock, down to the original shocks and springs yet the rear wheels are toe in looking from the rear of the car, I thought new Bilstein would solve the problem but when I lowered the car after the install, the rear wheels still tilted inward.

Is the problem the lower trailing arm bushings? Strange that both would wear out and tilt at the same angle. Oh and the chassis has over 176k on it so if it is these bushings, I would not be surprised.

I just need someone to tell me, springs?, bushings?, I am puzzled.

how do I fix this problem.

⟐ Commented July 20, 2022 at 10:20 MST

⟐ Answered June 08, 2022 at 18:08 MST