Has anyone replaced the original horns on their diesel (mine is an '82 240) with the metal Hella horns? Is it "difficult"? Suggestions? Also,I'm about to replace both fuel filters. Someone told me to fill the gas tank and then "bleed" the air. Is this true? If yes,how is it done? Again , is it "difficult"?? I realize "difficult" is relative,but I'd really appreciate some opinions from some of the seasoned vets of this great site. Thanks. Dave W.

I replaced both horns on my old 300D. Not hard at all. They're mounted behind the bumper on the frame rails.

Regarding the fuel filters, I'd recommend pouring the diesel from the old filter into the new one before installation. That way you won't have to prime it as much.

Filters are easy. A full tank isn't necessary but it is better than an empty one. Anyway you slice it priming will be necessary. Personally I prefer not not dump in fuel from the old filter. I pour in fuel additive or diesel purge but that's not necessary either. Remove both filters, install the new ones and pump the primer until you don't see any more bubbles in the clear fuel lines. If ultimately your car won't start you need to prime some more. It's a bit messy so expect to spill a little fuel in the process. Soup to nuts it shouldn't take more than 15-20 minutes. Less the next time you do it.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

Follow Irg's good advice. Don't use fuel from the old filter as it does contain dirt . This fuel could screw up an injector or two. I got some Power Service Diesel Fuel Supplement at Wal Mart and use it for this purpose. And I have it available to add to my fuel tank if I think that I got a bad tank of fuel.

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Paul 1987 300 SDL; 2000 ML; '69 MGB; '68 VW Fastback

Ah, silly me. It would be much better to fill the new filter with some diesel purge. The fuel from the old filter should be dumped back into the tank though, can't bear to see it wasted especially considering the diesel prices nowadays!

Thanks to all for the advice--just what was needed! Dave in Boston

The first time I did it was in May I think (of 2002) so it wasn't too cold out. The engine was also warm.

I did the pre-filter first (straightforward)

I then unscrewed the large hex bolt at the top of the main fuel filter housing then took the old filter out and just threw it away.
I didn't even put fuel or anything in the new one, put it back but I didn't tighten the hex bolt completely (as per the Haynes manual)

then I just used the primer pump (which wasn't leaking yet last year) for a while until fuel gushed out at the top, tightened everything up, and fired it up!

It idled perfect then the idle speed dropped so I just put the throttle down and it kept trying to die but after a while the revs rose back and I just took my foot off the accelerator.

Worked...

Second time I did it, it was really cold and the engine was really cold and the primer pump was leaking. This time I actually put fuel in the new filter but it just wouldn't start !!! until I primed it like a million times. It finally started.

The next day I put a new primer pump in and no more leaking pump.

I think maybe the warm engine and good primer pump help

Where are you in Boston? I am in the BU side of Boston if you ever need help let me know.

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2008 BMW 335i Coupe

I have thought about getting some of those Hella horns, but don't really want to spend the money on them. Some airhorns would maybe nice though

Where is the primer pump? Is it something that's suppposed to come with the car, or is it something under the hood?

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1981 Mercedes 300D - 300 000 km
1980 Camaro Z28

What about an air horn that plays "Dixie"...

Scott

It's on the driver's side of the engine, you will see the injection pump (a huge mechanical thing with fuel lines coming in and out of it.. can't miss it). On the left side (driver's side) of that pump there is a little thing either white or black in color thing that you can either screw out and pump or one that you can just pump right away (the screw out type is the old one)

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2008 BMW 335i Coupe

If it is the old style primer and it gushes fuel when you pump it you may need a new one. Mine did just that the first filter change I did, it still worked but was really messy so I replaced it with one of the new ones...... which is actually easier to use, you just push it.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Having a warm engine is a BIG help.

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Paul 1987 300 SDL; 2000 ML; '69 MGB; '68 VW Fastback