RK55H Hot Gas Tank

[g8erh8er]

I'm dealing with a hairline crack in my gas tank and noticed yesterday while checking on my patch job that after about 2 hours of mowing, the tank was extremely hot to the touch, like uncomfortably hot.

I don't recall my gas tank getting hot like this in the past, but then again I'm not sure I've ever made it a point to check its temp. Can anyone else confirm there's gets hot as well? I know the fuel filter has a line on it that will send gas back to the tank, just didn't realize the fuel would be sent back that hot.

2019 RK55HC with 570 hrs

 

[dodge man]

Just to be clear diesel correct? Where is the tank? If it’s near the engine or exhaust I’d say that might be normal. Uncomfortable hot seems a little unsafe. If it’s away from the engine and exhaust that doesn’t seem normal. A fairly large amount of fuel is returned to the tank and it will get warm passing through the engine bay but it shouldn’t be hot.

 

[g8erh8er]

Just to be clear diesel correct? Where is the tank? If it’s near the engine or exhaust I’d say that might be normal. Uncomfortable hot seems a little unsafe. If it’s away from the engine and exhaust that doesn’t seem normal. A fairly large amount of fuel is returned to the tank and it will get warm passing through the engine bay but it shouldn’t be hot.

Diesel. Here’s location of the tank relative to the engine. Seems like fuel is returning to the tank way too hot. No egine over temp warnings or anything like that though, and tractor runs good. I’ll have to use my temp gun on it next time to get an actual number.

 

[ptsg]

Your tractor has a Common Rail engine, which pressurizes the fuel to extremely high pressures, up to 40,000 PSI in some engines.

Pressurizing any type of fluid to high pressures will cause the fluid to heat, a lot. That's why they typically run a fuel cooler in common rail engines.

Checking the parts catalog for your tractor, I couldn't find one, so that would explain why the diesel tank gets so hot. Even with a cooler, the fuel temp typically sits in the tank at around 130F, give or take. So without a cooler, I can only imagine it getting much hotter.

 

[RjCorazza]

I would be interested in hearing what temperature you get on the fuel tank. My Kubota common rail has a cooler, and I have never noticed the tank getting particularly warm.

 

[g8erh8er]

Thank you for the explanation. You’re correct my tractor only has an oil cooler. Kinda seems like a design flaw to have 15 gallons of very hot fuel sloshing around in a thin walled plastic tank that’s getting vibrated, bounced, etc. No wonder mine has a crack.

 

[g8erh8er]

I would be interested in hearing what temperature you get on the fuel tank. My Kubota common rail has a cooler, and I have never noticed the tank getting particularly warm.

It’ll be another two weeks before I mow again but I’ll let you know. I will say I could only hold my hand on the portion of tank below the liquid line for a second or two before the pain was too great, so my guess is it had to have been in the 130-150 range.

 

[CloverKnollFarms]

What's interesting is that TYM makes this model, but the TYM is not common rail. RK specs a different engine that is... But must have forgotten to request a fuel cooler. Whoops

 

[ptsg]

This RK55 is rebranded from the TYM T554 which had indeed a common rail engine. This series of tractors was before TYM started using the Kukje mechanical engines in their models.

The T554 also didn't have a fuel cooler.

 

[CloverKnollFarms]

Oh. I thought todays RK55 was otherwise identical to the TYM 574

My bad. Sounds like TYM f'ed up.