1982 300GD- Fuel prime.... shocking right?


Hello all! This forum has been a wonderful resource for quite some time, so I felt it was time to come out of the woodwork finally and ask for some help. I have owned my 1982 300GD now for about 6 months and absolutely love it. She has some issues, the most concerning is losing fuel prime at inopportune times(after sitting for as little as 30mins) . It does have the new primer push style and not the older style. Unfortunately I have become well acquainted with this bulb. All the lines have been checked back to the tank and I have gone as far to add an inline diesel pump to push fuel up to the mechanical pump on command via switch, prior to ignition, this has helped considerably in "pump" time on the priming bulb when prime is lost. The braided lines have been replaced and double checked. Also, new fuel filter with new gasket. The vehicle starts brilliantly when prime is in good shape, first try. Idles beautifully. Shifts smooth and has all the power you might imagine a sub 100hp diesel might have. This leads me to believe that I am possibly getting air in the system somewhere near the high pressure injector pump. I would love to hear your thoughts on this, suggestions, things to check and double check. All help is appreciated, I have exhausted my reading on benz-world diesel threads. I enjoy this community and reading here, so this will be my first post. Thanks in advance for your time.



New member

A couple of things that I would do (if you haven't already) is to replace the valves in the lift pump housing (they come as a kit with the washers and are fairly cheap and relatively easy to do) and I would also be inclined to check the filter on the bottom of your fuel tank sender. Mine recently failed to bleed at all because of a blockage there which was caused by an anti fungicide treatment.

I hope that this helps



Perfect! Two things I've yet to try. I will need to do some background on those projects/parts and give it a shot this weekend, but in the meantime if anyone has foresight on the above mentioned fixes it would be greatly appreciated. I will keep this updated with progress for those in the future.


We have a similar problem wi our '85 300GD. I've still not fixed it (well I've not had the time to resolve it) but I would suggest joining clubgwagen as there is some SERIOUS knowledge on that forum.


Expedition Leader
there were plenty more cars than G's made with that motor. join a benz forum. and hit the 300d section.


Renaissance Redneck
I spent hours and hours working on an OM 926 powered snowcat the other day... It also lost its prime, and pumping that baby back to life on a hill in a snow storm in the middle of nowhere is a heap o' fun! Finally got it running, and finished the repairs after 14 hrs, then it blew a head gasket 4 hours later... What fun:)


pumping to life!

I know the excitement that comes with finally having your only way home fire up and idle. It's a crap shoot in the morning sometimes for me. As of late the "Great White Buffalo" has been cranking up brilliantly in the morning, so long as shes plugged up. When things warm up a bit I'm going to check my hard lines for a pin hole and also check the "low pressure" fuel pump and its internals, as suggested above. Cheers!


New member
G,,day to help the life of the 2 valves in the lift pump, make sure you have a pre filter inline before the pump.
also the slightest leak in any connections will cause this problem, allowing fuel drain back to tank.
the easiest way to check for leaks, is totally degrease , wash down , let dry. then start the motor and sprinkle liberally with talcum powder.
the powder quickly show any leaks /weaps.
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