I had a water pump start to leak immediately after removing the rad cap once. A surge of air caused the packing to start leaking on a '79 300TD (mine!)
Was it a concidence? I dunno. I think things finally get weak then some external event causes stress (in the form of pressure, etc) to make them ultimately fail.

Speaking of pressure. And back to the subject of this thread.
I recall someone applied pressure to the fuel tank I believe it was, on a vehicle with a 603 engine in order to force fuel into the filter after changing and I think it sort of primed the sytem.,
Does anyone remember that? Whodunnit? I'd like to try it but not on my car! :silly: I hate air in the lines and regret that there isn't a manual primer on the 603. Even filling the secondary filter one has to crank like a SOB to get it running.

In regards to the earlier comment that most people don't keep a small amount of diesel on hand to fill the fuel filter before installing it, I recall an earlier thread that contended that it MAY actually be benefical to fill the fuel filter with ATF, hydraulic fluid, Marvel Mystery oil of some other viscious fluid.

I'm sure all of you have some of one of these sitting on the shelf in your garage. Why can't this be used to fill the filter when you don't have any diesel on hand?

Read what is written and realize this poor fella's car sat dead for 3 days and draw your own conclusions. This guy needed help that made his situation better, not worse. Cracking injection lines dumps the fuel charge in the line. Understanding fluid dynamics and hydraulics, once air is present in the pump, its compressibility vs. liquids incompressibility will not allow it to displace liquid that is restricted to the extent that the injector lines are by the nozzle tips. Also understanding the pump design, by bleeding the filter at the filter, fuel integrity is maintained on the high pressure side of the pump and in the injector lines. The absents of fuel at an open injector line is most likely the lack of motive flow from the cavitated pump vs. the air at the injector. This is a self bleeding system. Keeping the high side sealed and not exacerbating the situation by introducing more air by cracking injector lines when the high side of the pump is most likely still solid with fuel would be a better process.

Interesting--I must say I'm jealous of the performance of your fuel system. I have vowed to NEVER let mine run out of gas, as I'd instantly call the tow truck along. I wonder what the difference is between your car and mine. I do know that my injection pump was recently replaced (in the last couple years), but overall I still don't know that much about the car (been driving it less than two months now) and need to do more research through the service records.

How much fuel do you see coming through the prefilter when cranking (if you've noticed)? I noticed that while cranking the pulses of fuel were relatively slow--approximately two per second, maybe, compared to a 600rpm idle, where the pulses are very quick.

Now that's an idea! Does this work? Does anyone have any such experience? Do you just pressurize the tank, and then crank, but with more efficient cranking, or will a pressurized tank actually force fuel through the system?

Does anyone make a fuel tank pressurizing pump for this purpose? If not, I'm thinking it would be interesting to cut a hole in a gas cap and rig up a small bicycle pump to it, and use this when changing fuel filters in the future.

Also, a naive question from a new owner: is there *any* way to flood a diesel engine?

If the tank is near full on a 124 sedan, the secondary is below the head of pressure of the tank fuel and it will gravity feed and purge nicely

A-ha! I only had a quarter tank of fuel while going through my starting trials and tribulations. This certainly sounds like a variable that could significantly affect pumping speed. Is it general practise to only change fuel filters with a full fuel tank?

Thanks!

Matt

Depends on the job.
 

I do personally AND, through the cunning use of a small catching vessel, I acquire the fuel I use to fill the spin on replacement. I slide the empty dry filter into its mounting area and using a small kitchen funnel, fill the filter from the mount bolt hole.(the mount bold pulls free from the filter mount bracket. The oring on top is the only one that seals anymore as the bolt has been modded to remove the inner oring lands) It takes a few goes at it as the element material absorbs the fuel and displaces the air. About 20 minutes of topping up should suffice. finger tighten the mount bolt so it still can leak, hold the shut off closed, have a helper crank the starter for a second or two until you have fuel at the bolt head and you should have purged the majority of any air that would trip you up!

Good Luck next change.

Although this may work, it is NOT recommended... all of those items are not designed to burn as fuel, but instead are lubricants. They can leave deposits on the injector and/or prechamber, and in general are not something you'd want to even burn diluted in a full tank of fuel. I'd still recommend Diesel Purge as the optimum liquid to pre-fill with, second choice being plain ol' #2 diesel.

:wacko:

Vegetable oil is not recommended either, yet many are burning this as fuel with good results.

Veggie oil is not the same as ATF, Marvel Mystery Oil, hydraulic oil, or engine oil. I'd run veggie in my tank, but I don't think I'd use it to fill a new fuel filter though.

:cool: