Author Topic: glow plugs=engine failure (Read 7545 times)

andy2 · « **on:** November 18, 2006, 04:48:33 pm »

I was wondering if anyone has seen or heard of an engine failure caused by glow plug tips melting off?This 93 passat AAZ that I was looking at had all the glow pulg tips melted off and gone through the engine.The glow plug control module is likey the cause here as the relay is working properly.The module must have a problem internally causing the signal to the realy to stay energized.I guess the glow plugs can only handle so much on time before the injected fuel literally cuts the melting hot tip off :lol: .The engine's last start up was fine (cold) indicating that the glowplugs were working fine,then by the time the cars owner suddenly noticed low power and smoke it was too late.The tips must have damaged the cylinder bore/pistions and rings as the engine has very little compression now.

Kudagra · « **Reply #1 on:** November 19, 2006, 12:22:12 am »

Ive seen them destroyed by ether...but usually there is more damage too...

QuickTD · « **Reply #2 on:** November 19, 2006, 12:44:50 am »

Usually the damage to the glow plugs is from poor injector spray pattern. A stream of fuel impinging directly on a glow plug will cut the tip off. Hard to believe all 4 would do it simultaneously though. Couldn't be a case of old fast glow plugs installed in an AAZ where duraterms are supposed to go? The AAZ controller keeps the glow plugs on for 3 minutes after the engine starts, fast glow plugs wouldn't last long under those conditions...

andy2 · « **Reply #3 on:** November 19, 2006, 09:55:02 am »

The GP relay is working fine I just think that the GP module was screwed up causing the relay to stay energized possibly until the car's owner turned off the ignition when he got home from his trip.These glow plugs could have been on for quite a while!

This whole desaster actually ended up melting the GP fuse holder so the terminals and fuse were just hanging in mid air.

Not sure if they were the proper glow plugs or not only that they look like they have been in there for a good while so that would'nt explain why this particualar day the engine decides to eat glow plugs and wreck its self.The owner probably had the radio cranked up and didn't hear the damage happen.This engine was in good shape when I seen it 1 month earlier I also cold started it with no issues!

Does this sound remotely believeable guys?

jtanguay · « **Reply #4 on:** November 19, 2006, 02:27:24 pm »

maybe the guy tried using ether for some reason? :lol:

i would think that before the gp's would be eaten up, that the fuse for them would blow... maybe they were ones that take less juice so that the fuse would never blow? only thing i can think of... because if they managed to stay on for a whole trip, the chances of diesel getting sprayed onto them would be very good...

andy2 · « **Reply #5 on:** November 19, 2006, 06:26:34 pm »

The glow plugs draw less amps as they get hot,so when they are glowing they may only draw 25 amps which would be fine for the 50 amp fuse.The fuse would only be useful as a safety for a short to ground condition within the glow pulg circuit.

The engine runs on about 2-3 cylinders now so I guess some of the glow plug tips have done more damage in some cylinders than others.Once the tip ends up sitting along the edge of the piston it gets crushed into the piston causing the ring(s) to get stuck and then the compression dissapers.

addautomotive · « **Reply #6 on:** November 20, 2006, 10:20:07 am »

I've had the glow plugs burn down in my AAZ just like you described. However, they were the old style plugs that weren't designed to stay on for 3 minutes. Burned all four of them right down to the nub!

Also, I've had an individual plug burn down like that due to a bad injector.

jtanguay · « **Reply #7 on:** November 20, 2006, 01:52:50 pm »

Quote from: andy2

The glow plugs draw less amps as they get hot,so when they are glowing they may only draw 25 amps which would be fine for the 50 amp fuse.The fuse would only be useful as a safety for a short to ground condition within the glow pulg circuit.

The engine runs on about 2-3 cylinders now so I guess some of the glow plug tips have done more damage in some cylinders than others.Once the tip ends up sitting along the edge of the piston it gets crushed into the piston causing the ring(s) to get stuck and then the compression dissapers.

hmmm makes sense... heat = resistance... that really blows! time to wire up a safety light

would the glow plug light not stay on though? maybe hard wire an LED right onto the glow plug power strip.

its nice to find out all these little problems... i would not have otherwise known about them without the input from everyone on this board

andy2 · « **Reply #8 on:** November 20, 2006, 05:38:55 pm »

Quote from: addautomotive

I've had the glow plugs burn down in my AAZ just like you described. However, they were the old style plugs that weren't designed to stay on for 3 minutes. Burned all four of them right down to the nub!

Also, I've had an individual plug burn down like that due to a bad injector.

Did any engine damage occur with the 4 glow plug melt down in your case??

The glow plug light on most if not all the 1.6 er's and all 1.9's is independant of glow plug on time.

addautomotive · « **Reply #9 on:** November 21, 2006, 09:54:45 am »

Quote from: andy2

Did any engine damage occur with the 4 glow plug melt down in your case??

The glow plug light on most if not all the 1.6 er's and all 1.9's is independant of glow plug on time.

I was lucky, no major damage. Not that I pulled the head or anything to make sure. I was away when it happened, and when I got back a couple weeks later it had been fixed, and my wife had been driving it. It was running fine and I didn't see any value in pulling the head at that point.

As for the glow plug light, I run an indicator light directly from the bus bar. Makes troubleshooting a lot easier. I also run wires to each plug, so I can check them individually if I start having trouble.

andy2 · « **Reply #10 on:** November 27, 2006, 08:47:32 pm »

Fineally some proof that I'm not making things up :lol:

http://www.putfile.com/pic.php?img=4112389

#1 cyl screwed big time #2 no good #3,4 are in good shape.I guess it was just about luck mabye all glow plugs make it through the engine ok mabye they all destroy the cylinders,in this case it claimed half the engine.Beware AAZ engine owners

.I sure hope that this is a 1 in a million chance of happening to someone else.I'm putting a 2nd glow plug indicator light on my car after seeing this It will indicate actual glow plug on time :wink:.I don't care if the odds of this happening are 1in a million!!

Also the glow plugs that came out are part # 0 250 201 051,are these the correct plugs for the 1.9??

andy2 · « **Reply #11 on:** November 27, 2006, 08:58:21 pm »

BTW anyone know where the possibe trouble maker glow plug control module is located in the passat (AAZ 93-95).It doesn't appear to be in the same location as the golf/jettas above the fuse relay panel?

jtanguay · « **Reply #12 on:** November 27, 2006, 09:26:36 pm »

holy crap... thats devastating damage... its probably because the 1.9 plugs stay on after the motor is started up... would it really make that much of a difference if they didn't stay on after a cold start? swap it for a 1.6 gp system

andy2 · « **Reply #13 on:** November 27, 2006, 10:06:31 pm »

Thats exactly what I was thinking about,1.6 GP system.

QuickTD · « **Reply #14 on:** November 28, 2006, 12:19:41 am »

Quote

Also the glow plugs that came out are part # 0 250 201 051,are these the correct plugs for the 1.9??

That doesn't even come up as a bosch number, possibly discontinued? Maybe the part number for the old slow or fast glows that were replaced by duraterms?

The proper glow plugs would be 0 250 201 032.