Delica Canada | Mitsubishi Van Club

After x amount of hours of research, I have still yet to come to a solid conclusion as to the benefit of using a heated pickup inside a wvo external tank on a vehicle.

The most common pro I hear for using a heated pickup is that it will heat the wvo inside the tank in very cold weather allowing it to flow to the engine.

The most common con I hear against using a heated pickup is that the cold temperature outside mixed with the hot temperature inside the tank (via the pickup) will cause condensation inside the tank allowing more moisture/water than normal in your fuel.

Take an ice cold drink in a glass outside on a hot day. Almost instantly, the water/condensation will cover the glass from the outside.
Cold inside + hot outside = condensation outside surface

Take that principle and apply it to a heated wvo tank.

Cold outside + hot inside = condensation inside surface

I have yet to use or hear of a wvo kitted vehicle that does not have a heated pickup that would benefit from using one.

Instead of a heated pickup, an inline pump would be more beneficial.

To test, I took a freshly made 45L tank and poured in 30L of hot wvo leaving an air gap at the top simulating a heated wvo tank when it was 5C outside temp. After a few mins, there was considerable condensation on the inner walls (top/sides) of the tank.

Discuss

Opinions would be great

Condensation occurs because of moisture in the air. If your tank us sealed well then water could not get in to condense. If there is water in there to condense it is in vapor form already so cold or hot it will still go through the system.

I don't know anyone who uses sealed tanks. They all have vented breathers.

I was thinking about that after I posted. Heat or not that would still let in water vapour though wouldn't it?

i have always run non heated tanks. however for Turtle, i bought the hot stick from www.wvodesigns.com
actually bought it for The Space Antelope but then Turtle came along. The reason for heating the tank is that when i was in Montana in March i could not run WVO. it was too cold. i will put a valve in the hose leading to the tank and likely usually have it shut off. if i am on a big trip to colder climes, ill be burning oil fast enought that there little time for condensation to affect the fuel.. i think
another CON is oxidation. WVO + Heat + Steel = Oxidation. solution: aluminum tank.

or get the steel tank lined

I had a sneek peek at Kuan's raw power hot stick. It is HUGE !

Water in air condenses when it cools not when heated. Thats why moisture in the warm summer air condenses on the side of your cold beer. If at anytime the temperature of the air drops below the dew point then condensation will occur. The dew point is dependent on the absolute humidity of the air, temperature and pressure.

So, Jesse you are correct that it can occur in the tank but it really depends on how hot that fuel stick gets, how cold it is outside, how much moisture is in the air and how much fuel is in the tank. So how hot is the coolant by the time it gets to the hot stick??? I don't know as I am not there yet in my install. However, I do plan on running the hottest coolant into the VM2 then HIH all the way back to the pickup in the tank.

This is a good discussion and may be a problem in our damp climate even though its not a problem else where. An in line pump would be beneficial to take the strain off the IP and just use heat right up to the tank but not in it.

Or insulate the tank to reduce the temperature differential between outside and inside.... (although may be harder to do in practice)

Should we start a parallel discussion about preventing a condensation in a stock diesel tank? What is a big difference?

Just thinking about this again - Profister is correct. There is no difference. Condensation is not caused by the heat its caused by the temperature of the air falling below dew point whether heated or not.

I've had both. First, aluminum tank heated via a metal coolant line running inside my tank (on Mitsushi) along with in-line fuel pump. Never had issues with cold weather or engine problem. Mitsushi has been twice across Canada on veggie and as far as I know still runs very strong.

Currently I'm using my stock tank for veggie which isn't heated but I added an in-line fuel pump. When it gets closer to zero, on the Hwy and usually going uphill I notice a fuel starvation. Probably due to the fact that my tank isn't heated and the oil is pretty thick. I simply switch back to diesel for the few seconds it takes to make it up the hill then go back to veggie. Not a big deal to me but might become more of an issue in colder climate.

Aside from heating the tank to solve this issue is that I could run 1/2" fuel hose instead of 3/8" and I could also run a coolant line along my fuel line, all the way to the back and loop it back (so up to the tank but not in the tank). I'm pretty confident this would provide me a problem free cold wvo system. And if really cold, I'd use a magnetic block heater under the wvo tank in the morning to get my wvo cholesterol down... or thinner oil)

Cheers,
Mr. D

So if I understand, in a heated tank the condensation would become evident after the system was shut down and the oil (air in tank) cools

dfnder wrote:So if I understand, in a heated tank the condensation would become evident after the system was shut down and the oil (air in tank) cools

i was thinking just that. solution? fill the tank completely before it cools (im guessing)

after oil wrote:

dfnder wrote:So if I understand, in a heated tank the condensation would become evident after the system was shut down and the oil (air in tank) cools

i was thinking just that. solution? fill the tank completely before it cools (im guessing)

The only reason you would have condensation is if your oil has water in it. If that oil is heated and releases excess moisture into the air in the tank you could get condensation. Condensation will not occur from heating just from outside air that enters the tank. Condensation comes from cooling.

Condensation occurs when the air reaches its dew point. Say air is 10˚C and has a dewpoint of 5˚C - if you heat that air to 50˚C it still has a dewpoint of 5˚C (if it contains the same amount of moisture and the barometric pressure remains the same). So if air is entering the tank from outside and no moisture is added you would get the same amount of condensation whether the tank is heated or not.

Make sure you have clean dry oil

I live in Winnipeg (yes it is dryer here but we make at least 1 trip to BC a year) and ran the system year round in my Chev. Suburban. We put over 100K on the truck with a hot fox, aluminum tank, insulated, water block Donaldson filter and a lift pump. Never had an issue with water that I'm aware of. The GM IP's are very tempermental and don't tolerarte adversity very well at all, yet, we had no issues. I will do the same system in my L400 with the lift pump only pulling a few PSI. I haven't figured out how much yet. That is my biggest question at this point.
Rudy