Tricks for removing glow plugs on Aluminum head? - PeachParts Mercedes-Benz Forum

asnowsquall · #1 12-17-2006, 08:35 AM

Recently purchased a 87 300TD and I have no idea when the glow plugs were last changed. PO is saying don't worry about the injectors as he used additives and there is no record of when they were last changed. So... at 187K I'm changing injectors and glow plugs and most likely checking compression at the same time. Any pointers on getting the glow plugs out without creating more work?
Thanks,
Dave

t walgamuth · #2 12-17-2006, 08:58 AM

whoah there partner.

i wouldnt change any injectorers unless i knew they were bad. they are expensive and rarely wear out. at that mileage i would be surprised if they are worn out. save your money for a while the car will undoubtably need other things.

as for the glow plugs, i would wait til at least one went bad before changing any of them too. it is a job on that motor. they can be tricky to get out without breaking them too. if you want to do something get some penetrating oil on the glow plugs in anticipation of changing them. also round up a reamer because it is a good idea to have one handy for the job. and finally if you do the glow plugs yourself, be very very careful. they are tough to get out and fairly easy to break off. if you break an end off it is a real problem to get it out without tearing the head off. and head r and r is expensive.

so some of the guys with more 603 engine experience will fill in more detail, but i would urge caution in these tasks.

in this case if it aint broke dont fix it may be a good rule.

tom w

RAYMOND485 · #3 12-17-2006, 10:08 AM

1984 300d Turbo 142,000
Use Pb Blaster Over Night, Turn Out And In 1/2 Turn, Than Use Pb Blaster, Use Reamer After Out

engatwork · #4 12-17-2006, 10:19 AM

Not trying to make lite of the subject RAYMOND if the car you have posted is the one that you changed the gp's in then that is a cakewalk compared to the '87

.

I'm in the boat with Tom - I would leave the injectors alone and change the gp's ONLY when you start having cold start issues. I have spent up to ONE HOUR getting ONE GP out on one of these engines.

Jadavis · #5 12-17-2006, 10:44 AM

Leave the injectors alone unless you know they are causing problems. The quality of what you can buy now new is most likely less than what you have installed now with 178K miles on them. Yes, the new ones can be that bad.

I pulled the intake manifold and did a bunch of other work while I was changing out my glow plugs. There is a guy in Texas who said he did his without pulling the intake. I think he had an SDL which has more room in the engine compartment. Do the resistance and voltage checks described here before you do anything else with the glow plugs:

http://www.dieselgiant.com/glowplugrepair.htm

One good note, they rarely break off in the 603 engine. It is the newer (mid 90's) MB diesels that have that habit.

-Jim

t walgamuth · #6 12-17-2006, 11:40 AM

i wouldnt try changing the glows without removing the intake. once in that far i woulnt stop til all the glows had been changed. unless i knew that some were really low miles.

good luck

tom w

Monomer · #7 12-17-2006, 12:29 PM

Tip from whunter:

-bring the car to it's normal running temp.
-quickly tear off the intake manifold
-Pull the plugs out whaile the engine's still warm.

a soaking of PB will also help.

miamirex · #8 12-17-2006, 01:29 PM

I have had the same thought about changing glow plugs and injectors. But alot of the crap is made in India and they are of inferior quality. German components are still around but hard to find. Really, if it aint broke, don't fix it is the best idea, agree, probably alot of other things that can be done if you really want to spend money. Your mechanic can easily help you figure this out.

t walgamuth · #9 12-17-2006, 02:53 PM

oh yeah, when you DO do it use bosch glow plugs.

glad your car is running good.

tom w

leathermang · #10 12-17-2006, 03:41 PM

I would not mess with injectors until there was some complaint which suggests they need work...

However, concerning the glowplugs, the TRiCK to getting them out of aluminum heads is that they needed to have been installed with antiseize compound on the threads.. so that really is a TRiCK after the fact...
But it brings up something in terms of philosophy... if these guys are correct in that they will probably not be a problem removing at this number of miles or years on the car... and you plan on KEEPING the car... then it might make sense to pull them and INSTALL Antiseize compound on them NOW....

t walgamuth · #11 12-17-2006, 04:55 PM

and while you're at it.....

may as well put in the new glow plugs!

bosch.

tom w

asnowsquall · #12 12-18-2006, 07:44 AM

Should have mentioned that the cold starts are rough like its missing a few cylinders. Will measure the resistance. I've got a Bosch injector test stand so I'll check for drippage, cracking pressure, and the spray pattern. I want a baseline before running WVO. It will be good to have extra injectors, and I may like to rebuild some sometime as I do have the testor. Like the idea of bringing it up to normal temps before trying to pull the GP's. If it cools down can the engine be run without the intake to warm it back up before the compression test? Wish me luck, I need to work on the W123 wagon first, and oh ya Xmas is coming.....
Thanks so much for all the ideas.

t walgamuth · #13 12-18-2006, 03:09 PM

if it is running rough for a little while after start up you may have bad glows but you also may benefit from an additional ten seconds pause after the glow light goes out before trying to start.

this is brian carlton's suggestion. it worked like a charm on my 350sdl.

tom w

justinperkins · #14 12-18-2006, 03:47 PM

I changed the #1 and #2 plugs in my 87 with relative ease, probably could have gotten to #4 and #5, but #3 and #6 are sneakily hidden without removing the intake.

I had no problems removing the plugs, just be delicate but with precision force. Should come right out. Lucky for me it was the #1 GP that had failed.

Ditto the injector comments, don't give yourself extra work just for a little piece of mind. It's a pointless job unless they're failing.

justinperkins · #15 12-18-2006, 03:50 PM

Quote:

Originally Posted by leathermang

I would not mess with injectors until there was some complaint which suggests they need work...

However, concerning the glowplugs, the TRiCK to getting them out of aluminum heads is that they needed to have been installed with antiseize compound on the threads.. so that really is a TRiCK after the fact...
But it brings up something in terms of philosophy... if these guys are correct in that they will probably not be a problem removing at this number of miles or years on the car... and you plan on KEEPING the car... then it might make sense to pull them and INSTALL Antiseize compound on them NOW....

I'm pretty sure nobody in their right mind would go through the trouble of pulling all 6 GPs on a 603 and just to dab some anti-seize on them and thread them back in. That's just asking for it.