Hi guys,

I've been a 240D owner and tinkerer for about 6 weeks now. I've read hundreds of posts and this forum is invaluable. I have 3 somewhat related questions at the moment.

1. I replaced the spin-on fuel filter recently and noticed that the bolt that it attaches to has a hole in the side of it. This is probably a really stupid question, but does it matter where that hole is? In other words, is it meant to line up with something or do you just crank the bolt tight and not worry about alignment?

2. I'm confused about the proper use of the primer pump, particularly what to loosen to let the air out. The previous owner told me to loosen the bolt that attaches to the spin-on fuel filter. But I have seen posts here that refer to other bolts called "bleed bolts". I have also seen posts that say you don't have to loosen anything, just pump. So what is the correct method and when do you know when you're done?

3. I have the old style primer pump, but just purchased the new style black one from Fastlane. To replace it, is it simply a matter of unscrewing the old one from the block and screwing in the new one? Anything else I should do/know? And how does the new one operate? It looks a lot different and there were no instructions with as to how to use it. Do you just pump it when needed and leave it? It doesn't seem to screw into a locked position like the old one.

Thanks for any help.

-Flop

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1980 240D 4-spd 185K (The Tooter)

You do need to loosen a bolt on top of the spin on fuel filter, but it's not the one that holds the filter on. There is another bolt that goes through a banjo bolt that has three fuel lines attached to it. Loosen that one, then pump the primer pump untill you get solid fuel out. Then tighten the bolt back down and you should be good to go.

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The new primer pump is a delight in comparison to the old one. You just push on it. Thats it. Now when changing out your old one I think it requires a short wrench. to access the hex shape at the bottom. Also I think the new one has a different size hex area. Not really sure of that as it has been awhile. Also if you do not wish to save your old primer pump just grab it with vice grips will usually do it. Other than making sure the new pump has a good base washer that is about it.

A crow's foot makes the job a lot easier.

It does not matter where the hole is located. The area that the bolt goes into is rounded and this allows the fuel to flow to the line.

When replacing the filter, fill it up prior to installing it. I use either ATF transmission fluid or Marvel Mystery oil. You could use Diesel Purge If you have it. Or just plain diesel.
Once you screw the filter into the receiving bolt Since it's already loose. Leave it just slightly loose and pump your primer. It does not matter which bolt on top is loose, your just trying to get the air out of the setup so the pump has some liquid to pump. When the "air" is out of the system ( it squirts fluid) then tighten the filter mount bolt, clean up the diesel fluid and start the car.

Don't know I have not done this yet.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Thanks for the responses. I've heard this car is "self-priming", so does that mean that as long as it will start, it will bleed the air out itself? In other words, is the use of the primer pump necessary if the car can start without using it?

I remembered another question for you. I am planning to test my glow plugs and was trying to locate them at the block. I found them, but what are the other 2 bigger things that attach to the block around the same area? I followed the cable collection from the glow plug relay to the block and it looks like 6 wires are coming out. 4 go to the glow plugs and the other 2 go to the items in question.

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1980 240D 4-spd 185K (The Tooter)

The 616 and 617 fuel systems are not self priming. If they were, there would not be a priming pump. Newer models are "self priming" by have to crank the engine for a while. A manual primer is a better choice, IMHO. I had a Yanmar diesel tractor that had bleed points that used bleeder bolts like a brake system uses.

The other connections, one is a temp sender, and I have no idea what the other can be with out pictures or detailed descriptions.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

You won't find them there. The glow plugs are in the head.

There is no need to loosen any of the bolts when using the primer pump. The banjo bolt that has all of the return lines connected to it has a small hole in it that allows air to escape back to the tank.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine