Yanmar 1500

[driftwood]

Ive got a 1500, After a new radiator it was still running warm (around 215) I installed the waterpump kit from Hoye. The directions are pretty bad, but the job an easy one. Also the belt was 1 inch too long. I just ran to the parts store & got the right one for about 8 bucks. The tractor runs about 190 on a warm day now. Wally

 

[Neat 1500]

Ive got a 1500, After a new radiator it was still running warm (around 215) I installed the waterpump kit from Hoye. The directions are pretty bad, but the job an easy one. Also the belt was 1 inch too long. I just ran to the parts store & got the right one for about 8 bucks. The tractor runs about 190 on a warm day now. Wally

thats good that it doesnt overheat now but the underlying problem is still there. they were designed not to have a water pump and not overheat. mine never runs hot even on the hottest of days working flat out. i think you need to keep looking for the cause IMHO

 

[clemsonfor]

I agree with Neat. Your fine now but as that radiator gets clogged more the temp will slowly start rising again. Im guessing your radiator is just junked up internally from years of use.

 

[kencunningham]

I believe if the mixture of anitfreeze is not correct then that changes the specific gravity, and that affects the convection current of the fluid to create a flow thru the radiator. Of course if you put a pump in it , then its a moot point.

 

[clemsonfor]

Ken your probly on the right track. Thats why a previous member said to drain it and make sure its only 25% antifreeze in the water. This i think is the max that yanmar wanted in the fluid.

 

[careyo63]

I run store bought 50/50 in my 2000 which has a water pump. Since you put the pump converstion on you 1500 doubtful 25% is the problem them. Of course IMO. My guess is the Radiator still has or developed another problem FWTW.

 

[Kyhunter42]

I flushed my radiator today and refilled it with the correct solution of 25% antifreeze. The fluid that came out was pretty nasty and there was a distinct difference in the 25% mixture I put in and what it had in it when I bought it. I believe the previous owner was using 50/50 mix.

Problems I found:
1. Bad radiator cap
2. Improper mixture of antifreeze
3. Gunk inside the radiator

I corrected all of those issues and it seems to be running fine without overheating. I mowed thick grass for 5 hours yesterday without an issue. Hopefully this has taken care of the problem. If it does overheat again what is the next step? Send the radiator to a shop to get it cleaned? Replace the radiator?

 

[careyo63]

The low mix is for the Thermal Siphon and "no more than 25%" here's a good article you can read up on. I'd almost put money on it that it was the Dirty Radiator.
Yanmar Tractor Overheating

 

[284 International]

Make sure to carefully clean the outside of the radiator, too. Dirt, chaff, wasp nests, and all sorts of other things can block the passage of air through the fins. Making sure the fins are clear really helps, and should be a normal aspect of pre-use inspection, I think.

 

[clemsonfor]

If you have a water pump you can use 100% antifreeze and not see a difference. The 25% is for the Thermosiphon system to work like 284 mentions. Something about the water moving in the system from the cool radiator to the warm engine.

If your still overheating, take it to a radiator shop and have them "rod" it out. It will work like a new radiator once they professionally clean it.