It looks like my 81 240D has a bad GP. Should I swap out all the GPs and the relay or just pull the bad part? It doesn't look like the GP or relay have ever been swapped, is it time for a complete change?

KingSlug

There's no reason to replace the relay if it's working correctly. Some folks like to change all the GPs at once, but I just change them as they burn out (like light bulbs). They are pretty easy to change on a 240D. Use Borsch GPs, not Autolite, Champion, etc.

If it ain't broke don't fix it.

__________________
1989 300E 144K

I respectfully disagree on this one- if you order 4 new Bosch glow plugs, get a new relay, too, as they have been revised over the originals- I put 5 new plugs and the updated relay in my 84 300td, and the difference in its cold start was unbelievable. The major difference with the new relay is that it keeps the plugs on longer after the engine has started, resulting in much smoother operation until it warms. For the short money, it was one of the best upgrades/repairs I ever did on my 123 wagon.

JAS

__________________
94 E320
71 350SL

That is a good upgrade, I have it on my 300D as well, but it is not required to fix his current problem. I don't remember the cost of the kit, but I think it was in the $200 range, compared to $10 for a new glow plug. I would definitely consider that kit if a new relay is needed.

I think it's "If it ain't broke you aren't trying hard enough"
Just kidding.

I with Craig on this one. A new GP will make a ton of difference in itself. I guess it all matters on how much you want to spend on the repair. You aren't going to hurt anything by just replacing the burned out GP's That is what I do.

__________________

What if it's about to break?

What if you're going on a road trip?

__________________
1987 300SDL 167k
1992 Volvo 740 140k
1990 Volvo 740 250k
1989 Volvo 240 269k

Anyone want to trade an old Volvo for an '87 300sdl?

The problem with electronics is you don't know when it may break. Sometimes a new one is more likely to fail than an old one. I usually carry one or two spare GPs, but the car should start with one bad GP anyway. If the GP relay failed completely, you could always jumper 12V to the GPs directly with a few pieces of wire. I guess you could carry a spare GP relay, but you can't carry a spare of everything that may fail. If the relay is suspect, I would replace it.

I mostly agree... except I would not use such off-brands as those Russian made "Borsch" GPs... or Monarch for that matter !!! I put my trust in the "Bosch" brand and I understand there is one other, possible made in France, that has a good reputation. So IF you don't have a set of quality brand GPs then you might want to replace them all as I recently did with my Monarch that kept buring out after only a few months of use. I put in an all Bosch set and have had no problems since... YET.

I definitely agree that you DO NOT replace a $100-$200 relay in such a case... not on a system that only stays on less than 1 minute at a time! I have all but decided that IF/WHEN my relay konks out, I'm putting in a strictly manual relay... one that will have a push button on/under the dash that you push and hold for what the driver thinks is proper amount of time... depending upon how cold the weather and/or car's engine is.

That's that what I think!

Sam

Are you referring to the Beru brand?

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

That works great if no-one else ever drives your car and you never plan on selling it.

Look at this thread:

http://www.peachparts.com/shopforum/showthread.php?t=88637&highlight=afterglow

__________________
Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY

I installed a manual system in my "79" (80 eng) several years ago and love it. I use a Ford solenoid with a 15 amp push button switch, wired through the GP indicator light. I will do the same thing with my "85" when the relay dies.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

How did you get it to go through the GP indicator light? Are there schematics available somewhere online? I'd like to do the same on my 82 300TD.

__________________
Currently driving a very clean 1985 300SD from the West Coast.

JMHO, but I'd replace them all. On my 190d 2.2, I had 3 bad so I didn't really have a choice but there weren't noticable symptoms until 2/4 were bad. My opinion is that replacing glow plugs is a pain so I'd rather get the requisite number of plugs, get my tools, and go after it. I also replaced the electronics as it came in the fast glow kit.

Sholin

__________________
What else, '73 MB 280 SEL (Lt Blue)
Daily driver: '84 190D 2.2 5 spd.