Warm Mornings/hard Starting 300d - PeachParts Mercedes-Benz Forum

renman · #1 08-22-2007, 12:49 PM

1984 300 D turbo 244,778 miles. I run regular diesel and use the diesel power cetane additive regularly.
Here are the facts:
1.) Fuel filters clean and changed 8/15/2007
2.) Valves adjusted @ 230,995 miles on 2/1/2006
3.) One glow plug replaced # 3 cylinder 198,770 miles in 2004
4.) Bango bolt & line @rear passenger side cleaned 8/20/2007
5.) New air filter 8/20/2007

Heres the problem: Previous to the last two weeks of operation this car started right off. The last two weeks the car has taken a fair amount of cranking to get it to fire. ONCE IT HAS BEEN STARTED AND HAS BEEN RUN A FEW MINUTES IT STARTS IMMEDIATELY AFTER YOU TURN THE KEY FOR THE REST OF THE DAY. This car runs really strong and gets right up and moves. Boy doe's cleaning that bango bolt of the goo really make a difference in power. Could the hard starting be bad glow plugs as the most probable cause for hard starting all of a sudden? HELP.

junqueyardjim · #2 08-22-2007, 12:54 PM

I suspect you're due for a whole set of those little jewels, about $65.00 at the zone, maybe a little less from Phil. It's only money and little time. Do it and report back.

MattBelliveau · #3 08-22-2007, 12:55 PM

Sounds like you fuel system may be losing it's prime. Have you notivced any leaks, or diesel aroma from walking around the car?

renman · #4 08-22-2007, 01:25 PM

Thanks for the quick replys guys.

Matt: No i haven't noticed any leakage or diesel fuel smell that would cause me to think i have a leak & getting air into the system. However I will thoroughly check that as a potential source of the problem.

If the glow plugs need replacing why does the car start immediately after it has been warmed up. I mean the starter runs, maybe 2 seconds and the engine fires and runs smooth.

junqueyardjim · #5 08-22-2007, 01:37 PM

Because the warmed up engine has a lot of residual heat remaining in it. If the ambient temperature is say 67 at night, then your car will cool down to that point. However, when it warms up to 90 in the day time, the block does not warm up very much. A little, a little more if you would open the hood and let the sun shine on it. And most any old Benzs just won't start without a healthy set of glos. That is why I said replace all five of them and be done with it. You probably have 2 or even three plugs that have a little life left in them. If you like screwing around with it, replace only the two that are totally dead, and a bit later you can do the whole thing again.

renman · #6 08-22-2007, 02:30 PM

Ordered Beru glow plugs from Fastlane/Roy. Ill report back on repair. Thanks for input all.

rrgrassi · #7 08-22-2007, 02:35 PM

Make sure to ream out the GP holes. I used a drill bit the same diameter as the GP tip since the reamer was out of my price range.

renman · #8 08-28-2007, 11:57 AM

Thanks for the input gentleman. I installed the glow plugs yesterday afternoon and except for needing to buy a few 1/4" drive deep sockets the job went without a hitch. Darn I had to run off to Sears and buy some more tools.

The engine started right up this morning. Last night I drove it around in the country where I live for a few minutes and it seems smoother and peppy-er. Do new glow plugs make a difference in power and performance?

junqueyardjim · #9 08-28-2007, 12:47 PM

Makes the car run better all around. Has the same effect as a wash and wax do. Didn't you ever notice how much better the old Benz runs when it is all clean and shinny?