not true.

the MB fuse is capable of sustaining 120amps for a short time, it's not an instant blow like an electronic fuse, or household fuse. it's designed to handle overamps for short amounts of time. also, when testing a single plug to voltage, you are subjecting the plug to much higher volts, than the bank of plugs would normally see, which raises the ampdraw.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

So on OM617, with five of the plugs, would draw 300 amps for about 2 seconds? And that would not blow the fuse?

Hmmm....

Let's approach this from a different angle. When a glow plug is cold, normal resistance on a good plug is ~0.7 ohms, agreed? V = I * R (last time I read Ohm's Law). V = voltage, I = current, R = resistance

I = V / R, = 12/0.7, = ~17.143 amps.

I'm quite sure that a ammeter with a range of 20 amps is sufficient to measure the current that one glow plug will draw.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Well, I think the car we are talking about has a parallel glow plug circuit, not a series circuit as found on '70s era MB diesels. Each plug should be seeing battery voltage. True, all four plugs drawing at once will put a load on the battery, so each plug may only be subject to 11.5 volts, but that difference is insignificant.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

I have did a first crank the last couple of days, after an overnight set. The temperatures have been in the 70's went I did the start-up test. The engine still gets resistive, stuttery and shakey for a while. It is definitely not a smooth start-up and run. Would this still lean towards the possibility of a dead or a marginal glow plug or plugs??

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Rebe

Could possibly be a bad glow plug or two.
Is it smoking on the cold start?

No starting it in the garage even, it doesn't appear to be any smoke in particular, that I have noticed. The little ones like it takes aren't that expensive. I am tempted to change all four of them. Is Bosch the best selection for them?

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Rebe

If you buy glow plugs. Buy Bosch. Cheaper than Beru last time I checked. Take into account though about the Beru thing, I haven't looked in quite some time.
Beru is ok. I don't like them personally though.
Make sure to have a good reamer. Anti-seize compound on the plugs too.
Some say it is better to NOT put anti-seize on the plugs afterwards, but do what works.

Is it possible to rent one of those reamers? Beings you would hardly ever need one again, I didn't really want to buy one.

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Rebe