filling new fuel filter
 

There is repeated advice to fill a new fuel filter before installing. Do folks buy a pint or so before changing filters or is there some way to pull fuel from the tank?

Thanks,
Sixto
91 300SE
81 300SD

My intention on the next fuel filter change is to fill it with Lubro-Moly diesel purge. That kinda takes care of two problems at once - replacing the air in the system and cleaning the injectors.

I suppose you could siphon some fuel from the tank.

Another option would be to use a regular gas can (emptied) to get some diesel at the filling station. Use what you need in the filter and dump the rest in the tank. Any small residual amount of gasolene in the can when you start won't matter, and any small residual amount of diesel in the can when you finish won't matter either.

Ken300D

If you don't have anything to put in the filter, don't worry about it. Just screw it on and pump the hand pump until the filter is full. You will know because you will here a hissing sound at the top of the main filter when it is full.

On the late models with no handpump, they are called self priming. It helps in those to fill the filter, but it is not mandatory.

Just screw it on and pump.

Have a great day,

A complete bottle of Red Line DFC will fill the main filter right up to the top. Pour it in, button everything up and fire her up and give it gas immediately to keep it running. The later ones, like Larry said prime themselves. Put the new filter on and start cranking the car till it fires evenly.

I would mention that Lubro-Moly diesel purge is made to be run "pure" by itself. The normal routine to use diesel purge is to disconnect the fuel line from the tank and take fuel from a jar containing only the purge. In fact the LM diesel purge smells like diesel, and I expect that diesel is a large component of it.

On the other hand, I'm not sure if it is a good idea to run Red-Line DFC "pure" or not. Probably won't hurt, but I can't even say for sure it will ignite. It probably will once diesel from the tank starts mixing inside the filter with the DFC.

Ken300D

I just use lubromoly diesel purge. It's about half diesel fuel anyways. Fill the filter, bolt it on, and start. Hardly takes any more cranking than a normal start. Saves wear and tear on the starter.

- Jim

Diesel Purge
 

According to the label diesel purge is 65% diesel fuel. Of course this is probably German diesel fuel which makes our stuff here in the states look like Hog Swill!:) I use either tranny fluid or diesel purge. Then again, I don't have the nice spin-on filters that you all are talking about, mine is a canister.

Fryerpowered, which one of your diesels has a canister filter? Is it your Merecedes or VW? I also own a 300TD and it has the same spin on main filter as any other 617 engine.

Rick
 

My '76 300D has the canister filter. All my VW's and my '84 300TD-T have the spin on type. I haven't really looked at it too closely yet, but wish there was a way to convert the old canister over to a spin on. They are easier to find. The only problem is I think that I would have to change I/P's too! On the W115 there is a fuel line that comes from the I/P to the primer pump and into the fuel filter. My primer pump bolts onto the canister, not onto the I/P. This is why I had so much trouble trying to get the correct primer pump a couple of weeks ago, it seems they changed it somewhere in the middle of the model year. Tom