In tank pump temperature?

norbert77

Veteran Member
Joined
Feb 2, 2022
Location
Petrolia
TDI
01 beetle
Very long story, son has an ML350 diesel. Few months ago at 250,000 miles the original fuel pump went, he noticed that she's always driving low on tank every time he gets in the car needs fuel. She once branded out of fuel. Today the vehicle just quit with a quarter tank fuel left I suspect it is the fuel pump, but does running low on fuel really heat up a pump? Because fuel goes through it and it should cool the pump itself and I'm pretty sure most fuel pumps at least the ones I've seen have a little container around them to keep the pump in a little bit of fuel. I don't know if the ML350 is like that or not. Pumps really overheat like that?

 
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TurboABA

Top Post Dawg
Joined
Jul 24, 2010
Location
Kitchener, ON
TDI
RIP-2010 Jetta 6spd 2014 Touareg Execline
There are theories floating around that running with less than 1/4 on CR systems can lead to hot fuel being "recirculated" through the system because there isn't sufficient volume for the heat to have time to dissipate, etc....

I personally don't buy it, because on both CRs that I've owned, I've hardly ever re-fuelled before the low fuel warnings. It is however possible that if you have accumulated floaty junk in your tank, once the level drops to a minimum, the pump suction can be restricted by the crud floating on the surface, and thus lead to issues......

I've never bothered to log fuel temps on a full tank vs an empty tank to try to validate "my beliefs", because I simply don't care enough to do so.
 

norbert77

Veteran Member
Joined
Feb 2, 2022
Location
Petrolia
TDI
01 beetle
There are theories floating around that running with less than 1/4 on CR systems can lead to hot fuel being "recirculated" through the system because there isn't sufficient volume for the heat to have time to dissipate, etc....

I personally don't buy it, because on both CRs that I've owned, I've hardly ever re-fuelled before the low fuel warnings. It is however possible that if you have accumulated floaty junk in your tank, once the level drops to a minimum, the pump suction can be restricted by the crud floating on the surface, and thus lead to issues......

I've never bothered to log fuel temps on a full tank vs an empty tank to try to validate "my beliefs", because I simply don't care enough to do so.
False alarm, the fuel pump connection came apart haha
 
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