Glow Plug Replacement Did I Miss Something? - PeachParts Mercedes-Benz Forum

shoe · #1 10-20-2003, 08:02 AM

I replaced the glow plugs in the 96 E300 this weekend, it seems to have corrected the CEL but now on cold first start of the day the engine does not run smoothly right at first as before. Did I miss something or did I get a bad set of GP's? After the first start it does fine. I removed the old ones and installed the new ones (Bosch Duratherm) The parts man stated that there were two different GP's listed but supposedly gave me the correct ones. Could they be wrong? I plan to ohm the gp's from the controller this afternoon to see if any are bad. Is this common to get bad gp's?

TomJ · #2 10-20-2003, 10:17 AM

Not a pro on diesels (worked on one and two lungers on sail boats for some years though), but it sounds like leaking (as in not using new heat shields), or still some air trapped somewhere.

Once it warms, thermal expansion will seal off some of the leak (as far as chamber leaks from the HS anyway) and once pressure is up, the air won't be as much of an issue.

Had this with small air pockets in a line for a yanmar diesel once (packed like a sardine into a crowded bilge), took forever to get all the air out, but what I couldn't get out with priming worked itself out eventually with running.

MrCjames · #3 10-20-2003, 10:34 AM

On a 96 I would think you either removed the intake manifold, in order to get to the glow plugs conveniently, or simply struggled working in the tight quarters. I recently discovered on a friends 606 powered vehicle, it had glow plugs replaced last year, burned one of the plugs in about 8 months. During replacement I discovered the plug that was burned was loose in the head. I do not recall him having an idle complaint but it did cause the plug to fail within a year.

Only other thought, did you ream the glow plug bores before installing the new ones?

shoe · #4 10-20-2003, 10:37 AM

Well that would be ok if I had broke the fuel system open. I never toouched the fuel system so I don not see how air could have entered.

shoe · #5 10-20-2003, 10:40 AM

Yes I removed the intake (much easier to get to them) but I did not ream the bores out. Never heard I needed to do that. What kind of tool is needed and would that affect the new GP's?

TomJ · #6 10-20-2003, 10:57 AM

Quote:

Originally posted by shoe
Well that would be ok if I had broke the fuel system open. I never toouched the fuel system so I don not see how air could have entered.

Right, now that I've actually re-read your post (was thinking you replaced injectors, not just GP's), loose GP's, loose wiring (check up the wires for a harness issue and cracked insul), not letting them heat soak long enough AFTER the light goes out? They may have a diff heat rating than what you took out too?

shoe · #7 10-20-2003, 11:06 AM

Thanks, I was thinking they may be a different heat range. Not sure how to tell though. I still have the old ones I may bring them to where I bought the new ones and see if they can shed some light on the subject.