glow plug light comes on, then I hear a belt screech - PeachParts Mercedes-Benz Forum

otto huber · #1 12-03-2009, 05:23 PM

I don't know if this was just a coincidence, but my glow plug light came on for a couple of seconds about 3 minutes after I started driving the car from a cold start, then I heard a screeching sound from the engine. The screeching was temporary. It sounded like a belt, so I checked to see if coolant had leaked from the cooling system 5 minutes later when I got home. The alternator belt felt very dry, maybe I should change it soon, since I don't know how long it's been on there. Is it possible that I'm having alternator issues that are affecting the glow plug relay, or light?
Also, I have an afterglow relay and glow plug wires in my garage that I've been meaning to put into this car. I've already upgraded to pencil type glow plugs by removing the ground wire from the first glow plug. Does anyone know the wiring involved to complete the upgrade? Thanks

winmutt · #2 12-03-2009, 05:47 PM

You have a dead plug I believe.

otto huber · #3 12-03-2009, 06:15 PM

Really? These Bosch plugs are only a month old. I'll check for loose connections at the plugs.

#4 12-03-2009, 06:39 PM

Either that or the relay is acting up and it kicked the GPs on while you were driving. The extra load on the alternator could account for the slipping belt.

dagObx · #5 12-03-2009, 06:44 PM

^^^^What He Said.......

scottmcphee · #6 12-03-2009, 06:51 PM

I think vise versa, your alternator / regulator is acting up, the belt is not helping, and your charge voltage went low, and some indicators lit on your dash. I've seen a few of the "sensitive system" indicators (SRS, lamp out indicator, etc.. ) flicker a bit when weird voltage issues hit.

In my case, the starter did not dis-engage, and was acting like a generator until finally it chewed its brushes... this lit some unexpected lamps on the dash. Just voltage related issues, not issues with the indicated system.

funola · #7 12-03-2009, 09:14 PM

Quote:

Originally Posted by otto huber

I don't know if this was just a coincidence, but my glow plug light came on for a couple of seconds about 3 minutes after I started driving the car from a cold start, then I heard a screeching sound from the engine. The screeching was temporary. It sounded like a belt, so I checked to see if coolant had leaked from the cooling system 5 minutes later when I got home. The alternator belt felt very dry, maybe I should change it soon, since I don't know how long it's been on there. Is it possible that I'm having alternator issues that are affecting the glow plug relay, or light?
Also, I have an afterglow relay and glow plug wires in my garage that I've been meaning to put into this car. I've already upgraded to pencil type glow plugs by removing the ground wire from the first glow plug. Does anyone know the wiring involved to complete the upgrade? Thanks

Sounds like you have a loose alternator belt. Replace the belt if it's cracked and tension it correctly and you shouldn't get that belt screech under a heavy elec. load anymore.

Graplr · #8 12-04-2009, 09:25 AM

On my SD the glow plug light would come on occasionally while driving. Turned out the GP relay was bad and may have been the cause of why I went through 3 alternators in a short period of time. I replaced the relay with the new style afterglow and the light has behaved as normal since and no more charging issues.

If the light comes on again while driving, this is the route I would take. On all my tests in the garage the GP relay seemed like it was working but clearly wasn't.

soothappens · #9 12-04-2009, 09:38 AM

My 240 does the same thing I also have the upgraded plugs. Its the altenator belt it does it only after start up . Its your belt saying " I'm giving it all I got" try tightening it or replace.

otto huber · #10 12-04-2009, 01:50 PM

Thanks guys,

I have an afterglow relay from an '82 240D in the garage which I will replace my current relay with. I've done a search, and there are plenty of instructions for the Bosch afterglow relay, but not the OEM relay from a later model. Does anyone have a link to that swap? Thanks

Graplr · #11 12-04-2009, 01:53 PM

Quote:

Originally Posted by otto huber

Thanks guys,

I have an afterglow relay from an '82 240D in the garage which I will replace my current relay with. I've done a search, and there are plenty of instructions for the Bosch afterglow relay, but not the OEM relay from a later model. Does anyone have a link to that swap? Thanks

I'm not familiar with your model but I believe the relays are interchangeable. It should be just pull the old one out put the new one in and hook everything up the same.

#12 12-04-2009, 02:04 PM

Quote:

Originally Posted by Graplr

I'm not familiar with your model but I believe the relays are interchangeable. It should be just pull the old one out put the new one in and hook everything up the same.

Yup, I believe it is just "plug and play," I have one in my 300D and it helps cut down on the smoke considerable for the first couple of minutes.

otto huber · #13 12-04-2009, 03:41 PM

The '82 relay mounts to the front left fender. So you're saying I can just splice the wires coming from under my dash and connect them to the wires on the '82 relay?

#14 12-04-2009, 03:45 PM

OPs, I didn't realize we were talking about a 79. Do you have the old style GPs?

Graplr · #15 12-04-2009, 05:56 PM

Quote:

Originally Posted by otto huber

The '82 relay mounts to the front left fender. So you're saying I can just splice the wires coming from under my dash and connect them to the wires on the '82 relay?

Hmmm...like I said, I'm not familiar with your model.

I thought the 79s had the same type relay. Apparently is doesn't. Here is a link to Fastlane with what the relay looks like- http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1979%40%401979&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6139%3AMBC%7C1489%3AED%7C10000129%40%40240D&keyword=glow+plug&subcatid=P:240809@@Glow+Plug+Kit&mode=PA

It doesn't look the same as the one on my SD, so I don't know if you can make it work or not. Sorry.