Engine Tank Heater ?

[BobT]

One problem that I have had with my Allis-Chalmers 190XT Series III tractor is the engine tank heater. It takes forever to warm the engine adequately enough for cold starting. I believe I know what the problem is but I have a couple questions about it.

First, I realize the best solution is to get rid of the tank heater and install a block heater but for now, I want to work with what I have.

Looking at the plumbing the tank heater is connected so that it draws cold coolant from the bottom of the engine block and then supplies the heated coolant to the top of the engine just behind the thermostat. To me this seems backwards because I believe it should be plumbed the other way around so the heated coolant enters the bottom of the engine block and exits from the top of the engine. This would also be more inline with normal flow. Heat naturally travels upward and like cooking on your stove or heating your home the best place for the heat supply is at the bottom.

Another problem that I have noticed is that the heated coolant gets hot enough to open the engine thermostat so the top radiator hose is also hot indicating that some (most?) of the heat from the tank heater is being wasted by heating the top of the radiator and not the engine block.

I’d like to try flipping the plumbing around but here’s my question. Can these tank heaters lay sideways or do they have to be installed vertical? To install it vertical means longer hoses and leaving it more exposed to potential damage. If I could lay it down it simplifies the installation a bit.

I do not know if this heater has a pump to force the coolant or if it just uses convection to move the heated coolant.

[Scott Stein]

call your local implement dealer which looks to be Villard Implement.

[Macgyver55]

I believe you can mount it the way you want Bob. Most (not all) heaters use a check valve system to make sure the water will only flow one way. Heating the water and letting it rise through convection will heat the most area more evenly. I'm sure it will work the other way too, but I agree with your logic in this case. Heating from the bottom up will result in more even heat throught the block. The main thing is to make sure that where you put it, that the heater flow is the correct way to match the natural engine water flow.

[delcecchi]

Is there any kind of pump in this heater or is it "thermo-syphon"? If you want the hot water to go down, you need to have something pushing it down. I think the idea with the normal tank heater is that the rising of the warm liquid draws cold liquid from the block, and causes circulation.

If you put it upside down I don't think water will flow at all since hot is lighter than cold and so the hot water can't run down to the bottom of the hose since the hose is full of cold water.

[BobT]

Quote:

The main thing is to make sure that where you put it, that the heater flow is the correct way to match the natural engine water flow.

The way it is connected now is the reverse of normal flow and that's part of the reason I think it would be good to invert the flow.

I don't know if this one relies on any kind of pump but I am inclined to believe that it does not because I have never heard any kind of cycling noise from it. Only hear a hissing as the heater is running and the coolant is heating up. I didn't give the thought of check valve. That does make sense but it would still rely on convection to move the coolant I would think.

Maybe my best bet might be to make sure it is mounted at least partly upright to maximize coolant flow whether it has a pump or not. I'm thinking that next summer I'll look more into replacing it with a block heater if possible. Doing that in the winter outside is a cold pain in the neck job.

[Surface Tension]

It sounds like it is hooked up correctly. Taking cold fluid from the bottom, heating it and then into the top of the block. The tank heater is what is circulating the fluid not the convection from the fluid in the block.

Those tanks need to be mounted vertical.

Another cheap and easy option is to add a lower radiator hose heater.

As long as your rad outlet is lower then the inlet to the block to where you can mount the heater somewhat vertical it will work. Will it work better then what you have?

[BobT]

I've considered that but to do it I would have to replace the lower hose with a longer one so I could create a loop deep enough to work. The radiator's lower opening is above the engine's opening so the loop would be necessary to get the heat to rise into the engine block and not back into the radiator.

[Macgyver55]

We probably should have asked earlier but what brand heater is it Bob? The different brands each have their own set of instructions. On the "Kats" brand heater, the HSOforum says to keep it horizontal, make sure the water flow of the engine matches the flow arrow on the heater housing and mount it as low as possible for best circulation. They have diagrams on there also for common applications.

[BobT]

I've been searching the net for OEM installation manuals but haven't had much luck. The label on the thing is worn to the point I can't tell the brand so I'm kind of in the dark there. It sounds like different ones have different mounting considerations to keep in mind. I'm probably best to keep it vertical. I was using it yesterday and stood by it for a while to see if I could hear any indication of a pumping action but all I heard was a steady hissing. This suggests to me that it probably relies on convection to move the coolant and vertical seems logical. I think next summer, when it's warmer, I'm going to take the time to find the frost plug and install a block heater.

[Tom7227]

If you try to put it 'upside down' a problem may be that as it sucks in the top layer of warm water won't it will trip the thermostat in the heater and shut it down? I assume (always risky) that they must have some sort of limit switch built in.

Out of curiosity - is the idea behind them to warm the oil so that it cranks easier? If so they wouldn't a heater that attached to the oil pan be most efficient? I think I've seen magnetic ones in ads.

How come is seemed so important to have a heater of some sort back in the 70's? I always was adding them to the families/girlfriend's cars. Now it doesn't seem to be an issue. Is this because of fuel injection, electronic ignitions, or that fact that I now park in a garage rather than the street?

I really don't know the answers.

[Macgyver55]

Now it doesn't seem to be an issue. Is this because of fuel injection, electronic ignitions, or that fact that I now park in a garage rather than the street?

Yes, yes, and yes to your questions. Add to that the lighter weight oils being used and easier starting is assured.

Magnetic oil pan heaters can be a handy simple backup for really cold days, but wont work on an aluminum oil pan.

[efgh]

The thermostat could be stuck open and allow the hot fluid to circulate the wrong way, It should be a 198 degree one for a diesel. Does your heat gague show in the normal range, middle or warmer?

[BobT]

Today's engines are far more efficient at starting than they were back in the 70's.

Consider oil. My truck uses 5w-20 compared to the usual 10w-30 I used in my cars as a young kid. The thinner oil makes it easier for the starter to crank the engine at colder temperatures.

Electronic fuel injection is by far better at cold starting. The computer is programmed to know precisely the fuel:air ratio needed as well. The old choke system was basically a poke-and-hope kind of thing and quite often resulted in flooded engines.

Each plug has its own coil mounted directly to the plug for more efficient energy transfer compared to the old coil, points, cap, rotor, wires, etc. Too many terminal connections between the coil and the spark plugs in the past and each one adds some resistance.

The ignition coils output considerably higher energy for the spark plugs. I don't know the exact voltages but I believe a coil from a 1970's vehicle typically produced about 30,000 volts. Correct me if I'm wrong but the plug gap was typically somewhere around .025". Today with the higher voltage output, spark plugs are gapped nearly double that at around .040" or more. Hotter spark = more reliable ignition.

Aren't today's engines using lower compression ratios too? That would also make it easier for the starter to crank the engine.

[BobT]

Quote:

If you try to put it 'upside down' a problem may be that as it sucks in the top layer of warm water won't it will trip the thermostat in the heater and shut it down? I assume (always risky) that they must have some sort of limit switch built in.

I think you've misunderstood my intention.

Right now the tank heater heats the coolant and this forces the coolant to rise naturally. The output from the tank heater flows into the engine side of the thermostat housing. As the heated coolant rises cold coolant is drawn from the lower part of the engine block.

What I mean to do when I say I will reverse the flow is to relocate the tank heater in a lower position so I can maintain the vertical mount as it is but now the top of the tank heater is low enough so that the heated coolant can flow into the lower part of the engine block and the colder coolant will then be drawn from the thermostat housing.

The advantages I think will be...

* The engine block will be heated from the bottom up rather than from the top down.

* The thermostat won't open unless all the coolant in the engine is hot enough to open it. By then the engine would be warm all over instead of just around the thermostat.

The way it is now, the thermostat is getting heated up by the hot coolant coming from the tank heater and it opens. The result is that the top of my radiator is getting hot instead of my engine block. I had to leave the tractor plugged in for over 6 hours today before I could get it started and it was relatively warm in the teens.

Tomorrow afternoon I'm planning on making the changes. We'll see if my theory proves out or not. Like I told another engineer once when we tried something. It'll either get better, worse, or stay the same.

[Surface Tension]

6 hours is too long and something is wrong.

Nothing wrong with experimenting in the routing. Keep in mind as a rule every installation will say your inlet should be the lowest point on the block. Your outlet should be on top the block. Often they use a Y at the cab heater hose(water pump) for the outlet. That should get you away from the T-Stat so the hot water isn't running into the radiator. The tank heater has an up side and check valve to it so you can't flip it around and push hot water into the lower block.

Is this a diesel and what is your oil cap? You should notice the block warming up in an hour. Could be your tank heater too small(watts) for your tractor.

[BobT]

Wow! What a difference that made. I rerouted my hoses so that the heated coolant entered at the bottom of the block and the returned coolant came from the thermostat housing. Got done, refilled the system and plugged it in. 1 hour later I went out and found the engine warm to the touch. Hit the key and it popped off like summertime.

I guess my theory was right.