DIY Glow Plug replacement. - PeachParts Mercedes-Benz Forum

WilliamJ · #1 10-01-2003, 08:55 PM

I did a search for an exisating thread on this but struck out....

Anyone have any tips. I am going at this 100% blind and will simply back track what i remove. I bought the whot kit including plugs and relay.

diesel don · #2 10-01-2003, 09:14 PM

I've done three sets of plugs. Pretty straightforward, except for which knuckles end with blood. As I recall, 4 and 5 were a bit harder to get to. Had half the tool box out by the end.

I have not done the wiring replacement however.

I did purchase a glo plug rheemer and used it this last time. Seemed to help a bit.

As I recall the nut on the end was 8mm while the plugs themselves were 12mm.

Don

WilliamJ · #3 10-01-2003, 09:16 PM

thanks.

Wasuchi · #4 10-01-2003, 09:20 PM

If it was me and I was replacing all the glow plugs at once I would remove the injector lines (the metal ones), that will make things a lot easier. It'll be harder to start of course and you have to be careful and cover the holes in the pump and injectors so you don't get dirt in them.

P.E.Haiges · #5 10-02-2003, 12:30 AM

WilliamJ,

I assume you are changing the GP in a 617 engine but the 4 cylinder engines are similar. All I use are 8mm and 12mm combination wrenchs and sometimes another combination wrench to lengthen the 12mm wrench to loosen tight GP.

I found it is easier to just loosen the 8mm nut on the wire connector. Then remove the GP with the 12mm wrench. Now with the GP out of the head, remove the 8mm nut completely so the wire connector can be removed. There is much less chance of loosing the 8mm nut this way. Replace GP in reverse order.

I assume you know how to hook the box end of a second combination wrench into the open end of the first combination wrench to extend the length to give you more torque. I frequently use this trick an old mechanic showed me. Although it looks like you might break one of the wrenches, I have never broken a wrench doing it.

P E H

#6 10-02-2003, 02:32 AM

I used a regular boxed end wrench to remove the nuts holding the wiring.
I purchased a ratcheting style boxed end wrench (about $6.00) from Craftsman to remove the glow plugs.
If you decide to buy the ratcheting style wrench, don't get the off-set style as it won't fit into the space on some of the plugs. (I have the 617 engine).
No fuss - No scrapes- No blood on the hands.
Took about an hour or so to do if I remember correctly.

WilliamJ · #7 10-02-2003, 07:49 AM

excellent! i ought to have the parts here today and will do the job saturday afternoon. i have ratchet style open end wrenches.

Ken300D · #8 10-02-2003, 08:09 AM

The job of putting in the new glow plugs will go a little easier if you have the glow plug reamer tool. This is because on some engines (mine anyway) carbon builds up around the glow plugs. You might notice the old glow plugs being a little hard to get out? Well, if that's the case then the new ones will be a little hard to get back in, and they won't be as effective because the carbon packed around them will bleed off their heat.

Much better to ream out the glow plug area with the tool - then the new plugs go in easily and heat effectively.

Also, the use of anti-sieze on the new glow plug threads will help you keep them from locking up in the head. I have not heard of this being a really bad problem, but the anti-sieze is a nearly 100% guarantee this will not happen.

Buy only Bosch glow plugs. All others are essentially no good.

Ken300D

leathermang · #9 10-02-2003, 08:37 AM

I don't know how you ' struck out'... there are 182 threads JUST on the diesel forum on " glow plugs replace ".....

here is just one great example of the stuff already posted...

Glow plugs: Should I use a reamer to clean out the carbon?

WilliamJ · #10 10-02-2003, 08:46 AM

thanks for the link...i did not see that one....

i have no reamer and no idea if the ones i bought are bosch.

P.E.Haiges · #11 10-02-2003, 09:04 AM

Where can I get the GP reamer?

P E H

diesel don · #12 10-02-2003, 09:19 AM

PEH

I just bought mine from Performance Products. You must know of them, but in case you don't, their phone number is 800.243.1220 and they send you the coolest quarterly catalogs. So you have two options:

1. buy one from there ($57 or so) or
2. borrow mine for the price of postage (its lightweight and would probably ship for a buck or so)

Don

leathermang · #13 10-02-2003, 09:33 AM

Good move Don... 723 people just put you on their ' need to email' list..... LOL

#14 10-02-2003, 09:43 AM

Everyone has good pointers on removing/changing glow plugs. We forgot one, a good day in advance spray the end and the middle of the threads on the plugs with some type of lubricant (e.g. PB B'laster). These have been in the head for about 100K + miles probably, if not more. You DON'T want to break a plug off due to stubborn threads.

ALSO-I posted a thread a few weeks ago about using a glow plug reamer. I think the thread was entitled "glow plug reamer usage" under the Diesel Discussion.

diesel don · #15 10-02-2003, 11:38 AM

Leathermang:

If 723 people have offered advice as helpful as PEH, then 723 people can use the tool

Don