rScotty
Super Member
- Joined
- Apr 21, 2001
- Messages
- 9,546
- Location
- Rural mountains - Colorado
- Tractor
- Kubota M59, JD530, JD310SG. Restoring Yanmar YM165D
Thanks for the replies. the head went to a machine shop and our mechanic checked the block and put a straight edge on it.the overflow tank is a bit of an odd factory set up there is a tee right after the thermostat housing with a line to the overflow/fill tank and then to upper radiator hose. not easy to see flow. tested the thermostat and cap. my pressure tester is pretty cheap but the system held 14lbs for 20 seconds which is what the tech manual says. I have an ir thermometer and its confusing. when overheating temp gauge goes into red and overflow tank is bubbling hot but most of the block reads less than 180.except by the freeze plugs and I get 220 and higher but that's also just below the exhaust manifold.from this point it will keep pushing coolant out. Radiator and hoses are warm but not hot hot. Just shut it down and thermistat housing is 200 upper hose reads about 160 but can hold it by hand.lower hose pretty cool. I did use a exhaust gas in coolant test and it is negative. any ideas Im willing to try. thanks again richard
Well, I don't know the cause of your overheating. Was the head gasket leaking or not?
But I chased "overheating warning" on our 2006 JD 310 for months before finding the cause and in the process of trying to dianose it myself found out a number of things.
One thing I found is that the IR thermometer guns don't measure temperature, they measure changes in infra-red radiation - called emissivity. Just like temperature, emissivity changes with the material doing the emitting. Paint is different than plated metal, and rubber is very different from any type of metal.
So although IR emissivity is related to temperture - unless your IR gun has an adjustment for emissivity, and you have the ability to zero that adjustment ....then you can only really tell if one thing is hotter than another.
Without compensating for emssivity for every different surface, no IR gun can measure absolute temperture. You need to be measuring the water temperature, not some other temperature.
Apparently we can't expect an IR gun to switch from the metal head to a rubber hose without rezeroing the emissivity against a known source. Doing that is a process, and there are IR guns that can do that, they are more expensive.
I also found out that our JD 310 has an "always open" bypass loop down by the water pump. So even if the thermostat was not opening at all, the bypass loop provides enough cooling for idling or light work. That makes finding the cause of everheating by trying to measure external temperatures even more difficult.
rScotty