How Hot Is Too Hot?

[j t huskins]

My B7100 gear drive that I have just restored is running hotter than I like to see at 220 to 225 while working the PTO hard with the tiller or bushog. Normal non PTO work temp. is 180 to 190. I haven't been able to find any max temp specs for this engine and I know that older model diesel engines had fairly low limits. Any one have any comparison info to help figure out if this is ok. The machine is all new and clean so there are no air flow problems to cause the high temps if they are too high.

 

[ibnxe]

Rebuilt engines will run on the hot side, early in the break-in process. What are you relying on for a temperature reading? Often gauging is inaccurate. If you can get your hands on one of the non-contact digital thermometers, you could verify that the temperature reading is correct.

 

[Oldtractorfixer]

180 to 190 is what your thermostat is. That is normal for a cooling system that has sufficient capacity for the load. So if it is not really hot outside I would agree you are on the top side. Did you get the radiator cleaned out on the inside when you did the engine. It could be paritally plugged. Make sure your fan belt is tight enough. It was probably new and may have loosened a bit as it seated. To check with the engine and key off try to turn the fan by hand. If you can without turning the engine it it too loose. My guess is plugged radiator.

 

[Thomas]

Does the radator cap whistles if to hot?
May want check radator hose.

 

[j t huskins]

I use a infrared thermometer to verify that the sending unit in the top hose is reading correct . The radiator was flow tearsted and good . The cap is new Kubota . The external head temp when checked runs very close to the gauge reading. The coolant is a 50/50 mix and is full. There is a slight loss through the overflow tube when at 220 but very little. The engine does not show any signs of overheating but those temps do worry me a bit. I wondered if anyone else who has a B 7100 with a temp gauge installed ever experiences these temps. The B7100 does not have a thermostat or water pump to fail and the fan belt is tight.

 

[Bluegill2]

225 is not too hot for a diesel tractor under load.

 

[KennyV]

With convection circulation you are going to be limited on how much you can load the engine... Too much load will generate Too much Heat, and you should be aware that you have to give it a few moments of less load to shed the heat that it generated during the 'overload'.... KennyV

 

[jonyyuma]

Be certain that you have nothing in front of the radiator except the screen. As always check for plugging of anytype in the fins. 220 is hot enough with the proper coolant..

 

[Thomas]

B7100HST 95 I had the radator cap acted like thermostat...to hot temp and it would whisle.

 

[kuboman]

Where does it run when under light load? Are you running it revved up? Has the fuel delivery been messed with.

 

[Looking4new]

Anti freeze is also anti boil. 50/50 mix will raise your boiling point to about 240*F.

 

[Raw Dodge]

Id say your temps are the absolute max Id run it at...your on the edge of causing damage..235 and above are when the heads crack at the valve seats,and the piston thrust side starts to wear thru the oil film and you run the risk of hot sticking a piston skirt,which always results in excess blowby after it cools and frees up,and runs again...Id try to find out why its getting so hot,whether its the radiator plugged internally or the temp guage is off by a few degrees.Id run less coolant ,more water,(IF your climate will allow)and a bottle of redline water wetter.....these engines go from long lasting bulletproof to forever damaged,scrap iron in just a few degrees of temp...

 

[j t huskins]

Where does it run when under light load? Are you running it revved up? Has the fuel delivery been messed with.

180/190 light load. Working PTO implements at about 1/2 throttle and not lugging.And yes on the injection pump. I am going to order 2 shims to adjust timing. Each shim will ****** 1.5 deg. Try one at a time and test run for results. I have been through the entire tractor during the restore and all of the cooling system is clean and working properly so advanced timing is the only reason that I can think of to cause heating under a hard load. When I tore the engine down I did not know at that time that the gasket under the injector pump was the timing adjustment so I did not make a note of the thickness.

 

[j t huskins]

B7100HST 95 I had the radiator cap acted like thermostat...to hot temp and it would whistle.

I replaced the old cap with a new Kubota cap and it has not whistled . The old cap would not seal and let coolant run out the overflow constantly.

 

[kuboman]

180/190 light load. Working PTO implements at about 1/2 throttle and not lugging.And yes on the injection pump. I am going to order 2 shims to adjust timing. Each shim will ****** 1.5 deg. Try one at a time and test run for results. I have been through the entire tractor during the restore and all of the cooling system is clean and working properly so advanced timing is the only reason that I can think of to cause heating under a hard load. When I tore the engine down I did not know at that time that the gasket under the injector pump was the timing adjustment so I did not make a note of the thickness.

Not knowing if the IP is out of adjustment I will assume it is ok. From what you have described indicates to me is how you are operating it. These engines rely solely on convection threw the radiator with the fan to move the air. I bet if you revved it up your temp under light load will decrease. 190 seems to high for an engine without a thermostat. Try full speed and see what happens.

 

[megaboz]

There is a certain optimum speed an engine should be run at for proper cooling efficiency. Every engine is different. With a mechanical fan this is critical.

As someone else asked are u sure the radiator is flowing coolant and properly, not just the air flow? Kinked lines?

As for other items that can aid in cooling is running good fluids. While the manufacturers oil is adequate there are much better oils and other fluids out there. However I have never been convinced on coolant additives, but that doesn't mean that there couldn't be merit to them.

You should probably check your exhaust temps at the manafold. If it is too hot there then you may have a fuel issue.

Just some random thoughts that pop into my head.