E300 1996 glow plug question - PeachParts Mercedes-Benz Forum

radunegru · #1 09-26-2008, 07:37 PM

My check engine turned on the other day, and the glow plug light does not come on until several seconds after the engine starts. Check the code ... and no surprise P0380
So what i did ... took the Ohmmeter and checked all six glow plug connection from the harness that comes to the relay.
It was easy!!! nr 3 glow plug is bad ....
Now the hard question, how can I find it. If I start counting from the firewall or from the radiator looks like 3 and 4 are easy to access without removing the intake manifold but only the air intake pipe.
First ...please tell me where the nr 1 is?
Second should I try to replace just the one or all of them?

spark3542 · #2 09-26-2008, 09:47 PM

Number 1 is near the radiator, number 6 at the firewall.

I replaced #4 GP without removing the manifold. When #6 went bad, I had to remove the manifold, but it ends up being much easier than I thought. Remove crossover pipe, remove black plastic engine cover, remove 14 torx-head bolts from the manifold. A few elec connections and vacuum connections and it's off.

Soak the GP with PB Blaster overnight before removing.

Diesel911 · #3 09-27-2008, 12:05 AM

Some members have had problems with the long Glow Plugs on your Engine breaking off inside of the Cylinder Head. I would take some time and read many of the Threads on this subject and how to reduce the chances of them breaking.

I would also consider what you plan to use to clean/ream out the carbon from the Glow Plug holes as Carbon buildup is one of the things that causes them to seize in the Cylinder Head.

When you install the new ones you might consider putting some Never-Seeze type compound on the Glow Plug threads as that is the other area where the seize in the head.

Jeremy5848 · #4 09-27-2008, 12:32 AM

I had no problems replacing #3 by removing only the crossover pipe. It was not carboned up and came out easily, I was lucky. My policy is to replace only the bad glow plug since the intakes are not that hard to remove. If I had to pay someone to do the job I would probably replace all of them.

Jeremy

TMAllison · #5 09-27-2008, 12:38 AM

My IM is different than yours. If you dont have a perfectly straight shot at the GP do yourself a favor and just remove the IM. It isn't that difficult.

I'd soak the GP with penetrating oil of choice for at least 3 days before attempting to remove.

Another member did failure analysis on old GP's held in his vise. They all snapped at 80-90NM. Personally, if it didnt come free by 50NM I'd soak it some more.

radunegru · #6 09-27-2008, 07:52 AM

thanks for the replay. I got myself prepared, read all the posts got the reamer from Phill long time ago along with MB oem BERU plugs and OEM anti size paste.
Now what kind of penetrating oil should I use? I have never seen PB Blaster.
Also is there any possibility to have a bad wiring harness on this year model?

Jeremy5848 · #7 09-27-2008, 10:14 AM

Auto parts stores should have PB Blaster in a yellow and white spray can.

Yes, it is possible to have a bad wiring harness (insulation failure), our '96 had problems with the wires from the transmission switch to the backup lights. Tray not to disturb cables more than necessary.

radunegru · #8 09-29-2008, 12:33 AM

Thanks a lot guys
It was a total success ...got it out than very easy. Then I have use the reamer to clean the hole. I did put some of the anti seize paste and then tight it by hand at about the same torque I have open it.
Reset the check engine light and now all is back to normal.