Hi Diesel 911.
Funny enough, last year I had a heat exchanger with glow plugs and I never had any trouble starting, even minus 6. I took it off as I didn't want to have a bother with the insurance as it was not declared ( extra electrical) and needed a bit of money and I thought it was not really any use ( I always had it and thought it was a normal starting )... But now that I know how much the pump is sucking, and how fast, I think that this device was actually giving the pump some help to start it all properlly.
Time to buy another one perhaps...

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E300TD year 2000. RUSTY SOLD
cost a fortune to maintain on the road
but run well on WVO
Second Merc died due to corrosion ( NOT rust) How can mercedes get away with that for so long?
Third lasted a month then went away...
Fourth now... Corroded too...