stock pump mounted externally?

anybody ever done this? i did recently when i mounted a fuel cell. let me know if you have and if there were any issues. some guys on another site had some concerns with it that it was unsafe due to it being designed to be in the tank. here are some pics.

stock "in tank" pumps are designed to be cooled by the surrounding fuel and therefore have no method of dissipating heat. I would expect a short life for the pump.

not sure about safety, but the pump is also design to pump fuel away from it, not suck the fuel, than push it too. I remember reading about how some fuel pumps are designed better for pulling&pushing as opposed to others that are just for pushing... something else to think about.

it also may or may not be self priming.... so if it was in the fuel tank it doesn't matter, but if it's outside the fuel tank and you run out of fuel, you might have to re-prime the line...

yes i understand that it will run a little warmer the way it is, but not any warmer that it runs when the tank is almost empty. i'm sure it will have a little shorter life than a pump that spends most of its life fully submerged. and yes all fuel pumps are more efficient at pushing fuel then pulling/sucking. that is why i mounted it lower than the tank so fuel will gravity feed to the pump which will also help the priming issues.

i run the stock pump externally in my tuff truck and so far its held up, gets warm at times but hasnt died yet

redneck23ms said:

yes i understand that it will run a little warmer the way it is, but not any warmer that it runs when the tank is almost empty. i'm sure it will have a little shorter life than a pump that spends most of its life fully submerged. and yes all fuel pumps are more efficient at pushing fuel then pulling/sucking. that is why i mounted it lower than the tank so fuel will gravity feed to the pump which will also help the priming issues.

Click to expand...

how do you use the truck-- daily driver, or trail rig? I can see it lasting for short trails and occasional use with moderate success, but as a "daily driver/ gotta rely on it now" pump, I would look for a dedicated external pump. If it was good enough for daily use, I don't think almost every OEM electric pump would be stuck in the tank.

Try shielding it to prevent being covered with mud and salt. Dried mud may insolate it aggravating the heat problem if any. Salt may eat up a pump normally protected by the tank.

Over heating. Try some kind of heat sink. Copper strip soldered to a stainless steal hose clamp. CAREFULLY tighten around the pump is one idea. Use heat sink compound (IMO)



Anyone who is capable of getting themselves made President should on no account be allowed to do the job." - Douglas Adams

Concur with those who have heat concerns - as mentioned, the OEM fuel pump (in-tank) is designed to spend most of its life cooled by the fuel in the tank. Seems funny to use something flammable as a coolant, I know - but it's no less odd than having something electrical in there in the first place...

If you're going to try a heat sink of some variety, I'd argue against using a hose clamp - too easy to overtighten and screw up clearances between the rotor and cell (most OEM fuel pumps are rotor/vane types.) Instead, use a good heat sink compound or thermal epoxy (thermally conductive permanent adhesive) to affix the sink to the pump.

Ideally, I'd agree with the rest. Use a dedicated external pump that can deliver sufficient pressure and volume, and probably stick heat sinks to that if possible. Also, mount it out of the way of mud splash and the like - mud is a great insulator, and can cause a fuel pump to overheat in short order if it gets all over the thing...

5-90 said:

Concur with those who have heat concerns - as mentioned, the OEM fuel pump (in-tank) is designed to spend most of its life cooled by the fuel in the tank. Seems funny to use something flammable as a coolant, I know - but it's no less odd than having something electrical in there in the first place...

Click to expand...

Very true! I was talking with a mechanic friend of mine, and he mentioned how he has replaced more fuel pumps in the last year or so than ever before. The reason is, due to the high price of gas, more and more drivers are not filling up their tanks. They add $10 here, $15 there, just in hopes that maybe tomorrow the price will go down enough to save $2.00 on a fill-up. Therefore, the fuel pump never gets submerged, runs hotter, and burns out faster.