Plastic return line cap melted? How to prevent in the future.

That’s correct and why in my return system I have the regulator bypass and IP return on a straight shot back to the tank.

ROCK HARVEY said:

We’ll I learn something new every day on this forum! I thought the excess fuel from the IP provided cooling to the injectors as it flowed past them, but if the experts say otherwise I 100% defer to them.

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Yes, and this same info about cooling the Injectors is in about every Diesel Forum out there.

I first hear it on a Mercedes Forum years ago, and if one person says it, it must be true, I read it on a forum.
Like an old Wives Tale..

Goat

typ4 said:

And this is why it has a fitting for an outlet on top so the pump is always full of fuel preferably bubble free.

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Never gave it much thought before why it was there on top, like a Brake Bleeder on a Slave Cylinder or Caliper, they are on top...air rises.

Goat

franklin2 said:

I had a Ford engineer on another board correct me when I said the fuel leaking in the return system from the injector was to cool and lubricate the injector. He got into this long explanation which I have forgotten mostly, but what I do remember is he said a brand new injector will have little to no flow into the return system, and as something inside the injector wears, the return flow will slowly increase with the age/miles on the injector.

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Thank You for posting this. I have been around and owned Diesels for a long time, and read a lot of books on Diesel Injection and how the various engines work etc....
Never read anything about the wear on the injector increasing the return flow.

So as the Pump and Injectors wear, the efficiency eventually slowly drops off, and the Injector doesn`t spray as much fuel on ea cycle. Then the engine slowly looses power, though we don`t notice it and the miles/years slip by.

Kind of like getting old....


Goat