Down hill hot, up hill cold?

[VT_Hokie]

I have a 1500D with no water pump ie thermo siphon and I have installed a temp gauge after I realized that my idiot light was not working. When I run the tractor under heavy load at full throttle (bushhog, dragging boxblade) that the temp will run up to 220 max going down a hill (70F outside temp). But under the same load going up hill the temp will drop down to 185-190. Is this normal? I was thinking that the warmer coolant was pooling at the back/top of the engine going down hill and the cooler fluid comming into contact with probe while going up hill. Some have posted that operational range is 180 to 190. Should I be worried?? Other specifics:

35% antifreeze to water.

Front mesh is cleaned out.

Radiator had not been rodded, but does not look corroded.

System has been flushed.

No exhaust gas residue or bubbles in coolant.

No coolant in oil.

Does not use coolant as far as I can tell.

Thanks for any input!

VT

[lens12]

I wouldn't worry.

[XmasTreeGrower]

My 1100D with the same thermo syphon does the same thing.

Just a quirk of this style cooling system.

[VT_Hokie]

Thanks for the information. Since I have some steep slopes on my property and prefer to bushhog some of it in reverse or going foward down slope, it gets a little unnerving to see that temp gauge swinging on the hot side. May need to come up with some kind of solution so that it does not boil over this summer...

[Jagmandave]

Do they offer water pump kits for the 1500 like they do the 1700? Lots of folks have added water pumps to their 1700s with good results........

[LMTC]

Do they offer water pump kits for the 1500 like they do the 1700? Lots of folks have added water pumps to their 1700s with good results........

Never seen one. What allows that on a 1700 is that it is the same block as the 2000, so parts fit. It would take a complete retrofit for a 1500 and I'm not aware of anyone doing that.

[normde2001]

Since so many guys do run thermosyphon systems in the 180-190 range I suspect you still have some blockage. I would "back flush" the system until water runs clear, and if no help, have the radiator professionally tested/cleaned.

[mjarrels]

Sounds like an old MGB that I use to own... only burned oil driving south? North, East or West ran like a top! Never could figure it out?

mark

[Tom_Veatch]

Sounds like an old MGB that I use to own... only burned oil driving south? North, East or West ran like a top! Never could figure it out?

mark

Probably had one of those magnetic oil pan drain plugs and it was interacting with the Earth's magnetic field.