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Tractor Talk Discussion Forum

IH 966 coolant leak.

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Author  [Modern View]

06-10-2021 14:20:11

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I have a IH 966 and when I was cutting hay I noticed it was running hot and then found it was leaking coolant from up by radiator some where. Switched tractors to finish cutting now Im looking at 966 and now it doesnt leak? I let tractor run at pto speed for awhile and no leak. What am I missing. Please advise I would like to get this fixed right ASAP.

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caterpillar guy

06-10-2021 18:54:33

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 Re: IH 966 coolant leak. in reply to jacksonduper, 06-10-2021 14:20:11  
From 40+ years of experience with IH tractors They tend to have plenty of coolant capacity in them. This is from an H to the 4166 and several models in your vintage and sizes bigger and smaller. Start by checking the level. It does not need to be full to the top. Just cover thwe core tubes by an inch will be good. Then check for circulation with the cap off. If good then look at the rad on the outside if you can;t see a light through it you need to clean it out good. Then should be fine run again and watch if still a problem then pull thermostat and heat with candy thermometer to see when open if it is at the same temperature as is stamped on it. Or around 160-180 degrees. If good then is fan belt tight and pulleys not worn out with big ledges in the vees. Fan should not be readily turned inside belt either direction though one way will usually trun easier than the other.

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37 chief

06-10-2021 18:38:11

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 Re: IH 966 coolant leak. in reply to jacksonduper, 06-10-2021 14:20:11  
Here is what happened to me. I bought a new radiatorI worked for a couple weeks. then steam everywhere from under the hood. I jumped off and saw a stream of coolant cmming from the top seam of my new radiator. I took the radiator off and took it to the radiator shop. They checked it and no leak. I put the radiator back on. after a while same thing leak coming from the radiator. The problem turned out to be the top radiator hose had a hole and only leaked when some pressure was built up. All this to say make sure the top hose doesn't have a hole and only leaks under pressure. Stan

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Bruce from Can.

06-10-2021 15:52:27

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 Re: IH 966 coolant leak. in reply to jacksonduper, 06-10-2021 14:20:11  
You need to pressure test the coolant system to really be sure where the leak is

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06-10-2021 15:18:37

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 Re: IH 966 coolant leak. in reply to jacksonduper, 06-10-2021 14:20:11  
Need to determine the source of the leak.

Is it possible it came from the overflow tube?

If the radiator was overfilled, or it got a little warm from the load and possibly grass stuck in the radiator fins, then some overflow is normal. The cap could also be getting bad. Look at the rubber, see if it is rotten or deformed.

If you suspect the radiator itself is leaking, fill it with coolant, look for leaks. If nothing, use a rag as a gasket, hold the exhaust from the shop vac over the filler neck to put some pressure on the system. Don't try this with shop air, too easy to blow out an aging radiator.

Also look at the water pump. Feel for loose bearings, look at the weep hole. A leaking pump can sling coolant in any and every direction.

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06-10-2021 14:59:54

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 Re: IH 966 coolant leak. in reply to jacksonduper, 06-10-2021 14:20:11  
How hot...abnormally hot or a little hotter than normal?What is ambient temp outside?Have you checked coolant level in radiator?Radiator cap good?Best way to find coolant leaks is to pressurize cooling system with a pressure check pump.Can buy/borrow at auto parts store.Also make sure radiator core is not plugged...both inside and out.Check operation of thermostat.If/when refilling cooling system make sure coolant has the proper amount of supplemental coolant additive(SCA) added to prevent corrosion,scaling,acids and protect against cavitation.

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06-10-2021 14:43:34

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 Re: IH 966 coolant leak. in reply to jacksonduper, 06-10-2021 14:20:11  
Coolant can push out of the radiator cap if the level is too high. These old tractors use the top tank as an expansion space. Fill only to 1/2 the distance to the base of the cap neck from the core. If it was actually hot it would boil much more out when it was shut off. You didn't mention checking the coolant level before of after the event, so I guess at this answer. Jim

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