2nd Gen Non-Engine/Transmission Steam? from fuel tank

[TboneMan]

Well, I just got back from a trip to Florida.



I towed a 5600 lb utility trailer down for a buddy of mine who moved there last year.



The air temps were in the high 90's, boost in the high teens, EGT 900, and water temp 195, and the fan sounded as though it was half engaged constantly and fully engaged going up hills, for 12 hours.



Knowing that the fuel is used to cool and lube the VP44, I made sure I had 10-12 gallon reserve in the fuel tank as a heat sink.



Well, two of my fuel stops (the hottest two), I notice what appeared to be "steam" evacuating the fill hole as I pump fuel in.



I've never seen phenomena before!



My thought was that as I pump fuel in, vaporized fuel in the tank was escaping.



Does the fuel in the tank really get that hot???!!!



Is this normal?

 

[mikel]

Yeah, the fuel in the tank can get that hot, and it is normal.



What you saw were fuel vapors coming out of the tank.

 

[Steve St.Laurent]

I ran a 5 gallon jug for a fuel tank one time (had to remove my tank and deliver my truck for some repairs - https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=40800 ) and did a check of fuel temps with an ir temperature gauge. We went on a 10 mile drive driving sedately (not getting on it at all so I didn't tip the tank over). The fuel started at the ambient temp of 50 degrees and after 10 minutes in 50 degree weather it was 105! That fuel gets HOT.

 

[WestTN]

The fuel gets hot form cooling the VP, but there is also a heater in the fuel system that runs all the time. Those temperatures are normal.