Primary Filter Question
 

Does anyone know what micron level the primary filter filters down to?

Thanks!

Just to be clear, the Primary filter is the clear plastic one. The secondary filter is the spin on filter.

-Jim

150? :D

I think the secondary is down to like 5-10 micron.

I am interested in the primary filter, and I do know it's the clear plastic one.

I started running B90 after diesel shot up to $3.09 and now the primary filter keeps clogging daily. I also have the Stanadyne FM100 w/the water/sediment bowl after the primary filter. There is brown gunk in the sediment bowl as well. I was thinking about putting the FM100 before the primary just to get more filter surface area, and I can dump and flush the sediment bowl instead of changing filters. The FM100 filters to 30 microns.

Sounds like you either have an fungus problem in the tank, or a lot of old sludge in the bottom. The pre-filters can be rinsed out if it is getting plugged up a lot. Just flush water through it the opposite way, and then dry it out really good.

If this keeps up and doesn't seem to stop, you may want to clean your tank out.

I just changed mine after probably 7-9K miles. I was shocked to see how full it was. Unfortunately I don't remember the mesh or micron rating of the filters/screens.

-Jim

It's a lot of sludge. I first thought tank strainer, but it was good.

I found carb cleaner to flush the primary filter really well also. I know it's not fungus, as the carb cleaner dissolves it also.

I also blew out the supply line, after checking the strainer. Fuel flowed just fine before blowing the line. I did find that the mity vac is a lot easier to use than the primer to fuel from the tank after the lines were cleared.

Personally I'd also probably use carb cleaner or brake cleaner to clear the pre-filter....they are great products. What CAN'T they do? :D ;) :eek:

However, NAPA brake cleaner is weak. Use Autozone or CRC, much stronger stuff. :D

Clogged filters
 

It sounds like you are either getting bad fuel or your tank has algae growing in it. I think the Mercedes designers were well aware of the potential algae problem when they put three filters in the fuel system. The tank screen gets the big stuff, the primary the next and finally the screw on filter gets most of what's left. I don't know what ends up going through the pump and injectors. If you do have algae, the only cure is to yard the tank and have it cleaned and then treat the fuel with a chemical to kill the algae residue. I used a product called "BioGuard" from a marine supply store. Pulling the tank is not a tough job and it will give you a chance to check the fuel lines under the car. The tricky part is using the fuel down to the point where you only have a gallon or so to drain out.

I think RR understands/checked all that - and essentially he got his answer. If the primary is really 5-10 micron and the other one is 30....it would make sense to switch them around, right?

Oh and just curious, how long have you been running the B90 thru it? I know you said since dino went up....but is this the first real usage of bio? The plugged filters will probably taper off here soon anyway.

When Dino hit $3.07 about 3 weeks ago, I went back to Bio. I was using bio off and on through the winter, and during spring and summer was running straight dino.

I'm thinking it's just the system getting cleaned out. I filled up w/bio again today. Soon itwill be B100, but if winter is going to be cold like they say, I will blend.

I am not running any SVO/WVO. I tried that, and the Stanadyne trapped and held it. Learned my lesson on that one. It was a gooey mess.