YM3110D Overheating - Time for new radiator?

[rScotty]

Have you considered your gauge is not calibrated or just reads lower?

Take your IR thermometer and bush hot in 97f for 3 hours and get off and measure the top of the radiator, I bet it's hotter than 160.

I wonder how the IR thermometer readings relate to the temperature of the water inside the radiator, and how either one compares to the heat of the head & block?
rScotty

 

[coosa]

I wonder how the IR thermometer readings relate to the temperature of the water inside the radiator, and how either one compares to the heat of the head & block?
rScotty

I have wondered that too, and have taken a whole lot of readings on both of my tractors over the past couple of years. I've checked a lot of other things, from the air coming out of my various AC units, to the temp of the grease when frying chicken. Mine has proven to be reasonably accurate; I think in most situations it's close enough.

I don't know if the temp of the top of the radiator is exactly the same as the temp of the water inside, but I think it's close enough to tell me what I need to know. I never take just one reading; always get 4 or 5 if I an really concerned. There is usually 2 or 3 degrees variation across the top of the radiator, and the bottom is usually 30 degrees or so cooler. Letting the tractor idle will quickly result in temp readings on the radiator that start dropping immediately.

The block is always cooler than the radiator, and the head is usually hotter. You get a lot of variation on the head depending on where you take it. I think that the temp on the top of the radiator beside the inlet hose is the one that tells me the most. If it isn't the exact temp of the water, then it is close, and it certainly seems to be directly proportion to the water temp.

These are just conclusions I've reached from using mine a lot, and I could be wrong about some of it.

 

[clemsonfor]

I would think the top of the radiator or upper hose would be good enough for what we're doing, I have no idea the temperature difference and water in the block. You could also maybe take readings on the head and block to compare. As to what these variations are across the different items and how that differs from the gauge temps it might be good if someone with something with a known good gauge takes some readings. It won't be the same on every application but would be a good general comparison.

 

[California]

Back in Post #31 in this thread I linked to an old thread where I posted 'infrared' readings for head, block, exhaust manifold, radiator top and bottom etc. I think what I observed can be considered typical for a Yanmar. (The thread is a little longwinded because I was primarily troubleshooting apparent low oil pressure - only to conclude its sender was bad).

 

[normde2001]

The coolant is never hotter than at the top of the radiator, (just leaving the engine), then cools as it passes down through the radiator.. Combustion temps in the head reach 800*F.

 

[clemsonfor]

The coolant is never hotter than at the top of the radiator, (just leaving the engine), then cools as it passes down through the radiator.. Combustion temps in the head reach 800*F.

that's in the head, i think were talking on the side, outside of it, where one would take surface IR readings.

 

[drunderw]

So I finally was able to do a burping of the system and all the air and bubbles are gone. I ran the tractor today bush hogging and it crept toward 225. I noticed when I open the hood it would cool quickly to 190 so I decided to try cutting with the hood open. I was able to go through 1/2 thick ragweed about as tall as the hood and do so uphill without topping 200 with the hood open. Any idea what that means?

 

[rScotty]

So I finally was able to do a burping of the system and all the air and bubbles are gone. I ran the tractor today bush hogging and it crept toward 225. I noticed when I open the hood it would cool quickly to 190 so I decided to try cutting with the hood open. I was able to go through 1/2 thick ragweed about as tall as the hood and do so uphill without topping 200 with the hood open. Any idea what that means?

Sure. It sounds like it is another variation on the same known Yanmar airflow problem that we discussed last month. Good on you for continuing to experiment until you found something that worked. Now you can simply refine the air flow so that you can close the hood.

It's not a new problem for Yanmar. Yanmar has been posting technical bulletins about that deficiency in their cooling air flow for years & years. It was common conversation among mechanics 30 years ago... The tech bulletin I attached is dated from 1983 !. see post #14..
luck, rScotty