glow plug replacement + compression test 85 300D
 

Bought new Bosch Duraterms to replace the old (and slow) heating glow plugs and did a compression test on all five while I was in there using my custom glow plug compression test "system". Start to finish took 1.5 hours. Is that a pretty good time? Have pics and videos, will upload and post links later.

Sure, it's a pretty good time. Lots of folks struggle for a while with the 5th glow plug at the very back.

I know mine took about three hours. However, it's because the previous owner, or their mechanic, rounded off the #4 and #5 glow plugs and gave up on removing them - they had only replaced the first three whenever they replaced them previously. So, of course, it was the #4 and #5 plugs that were bad :)

I ended up using needle nose vice grips to unscrew them. It was further complicated by the carbon buildup being sufficient to "grab" the tip of the plug, making it a slow, squeaky removal even once they broke loose.

Was your experience pretty easy in comparison? Or did you have any complications?

Here is my #5 plug after removal -

http://i.imgur.com/hKHKXR9.jpg

Here is the #4 plug being tested after removal - weak glow

http://i.imgur.com/k6x5drk.jpg

Here is the #5 plug, totally dead

http://i.imgur.com/cmHXVYv.jpg

Compared to a nice fresh Bosch plug

http://i.imgur.com/2ATKTOX.jpg

so when you test glow plugs, do you hook the glow plug up to a car battery and put - were the plug grounds to the engine and put + on the end of the glow plug and then see how red the tip gets?

Yes, basically.

In my case, I used a 12v jump pack. You can see it in the background of the pictures.

thats very fast,it takes me awhile the last two plugs are a pain.I don't remove the metal fuel lines.

All 5 Beru's (probably the original ones from when the car was new) came out easily this time since I had removed them a few months ago to convert from 8 mm nuts to quick disconnects and also reamed the carbon. I took the car for a drive to get it nice and hot and pulled all 5 glow plugs in about 10 minutes (injector lines not removed). The compression test on the 5 holes took 35 minutes per the video time stamps. The secret to the speedy compression test is push lock fitting tapped and screwed onto a modified HF brass compression adapter (the one with the Schrader valve). The push lock connector accepts a 1/8 " o.d. nylon line which connects to the 0-1000 psi HF gauge via JIC flare fittings (which is where I release the pressure). It seals very well and does not leak down after pressure peaks when I stop cranking. This pic is cyl #5 which I did first since it is the most difficult one and requires using long nose pliers to insert the nylon tube into the push lock fitting.

http://i31.photobucket.com/albums/c3...904_100355.jpg

Here's the videos of the tests. Click to play. Not happy about #2 and 4. I'll recheck those two, maybe it was dirt on the adapter flare not providing a good seal? If that's not it, do another valve adjustment. This car does not get driven much maybe from sitting too much?


Cyl #5 465 psi
http://i31.photobucket.com/albums/c3...00D5465psi.jpg

#4 420 psi
http://i31.photobucket.com/albums/c3...00D4420psi.jpg

#3. 460 psi
http://i31.photobucket.com/albums/c3...00D3460psi.jpg

#2. 300 psi
http://i31.photobucket.com/albums/c3...00D2300psi.jpg

#1. 465 psi
http://i31.photobucket.com/albums/c3...00D1465psi.jpg