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brewcrew

bobcat trouble

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I've got a small Bobcat (model 463) with a little 3-cylinder Kubota engine. Lately when I work it hard for more than a half hour or so it starts acting like it's overheated. But the heat gauge won't move at all- stuck on the lowest temp. Would a stuck thermostat cause the temp gauge to not move? I've checked the radiator and it's plump full, and the overflow tank reads correct. Any other places to check to diagnose it?

 

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Shoot it with your thermal temperature gun in different spots. See where it gets hot first.

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Brew

      By all means, get the temperature gauge fixed.  If you haven't already done so, you can destroy this engine.  Now to diagnose your problem.  The first thing that I would do is to look through the radiator fins with a trouble light on the opposite side.  Look very carefully and be sure you can see the light, unobstructed, and at all areas of the radiator.   I you can't see through the radiator fins then that part of the radiator is not cooling.   

     I'm an old man, and have worked as a professional mechanic for over half a century.  In that time frame I have changed a lot of thermostats but I would say I could hold all the genuinely bad thermostats in both hands.  They get blamed for a lot of overheating problems, but really are not the problem.

      The next problem that causes a lot of overheating is corrosion building up in the flues of the radiator.  This is very difficult to find.  The only way we can get a peek in a radiator is through the radiator cap opening and the top and bottom hose connections.  Unfortunately on these small engines the openings on the radiator are very small and do not allow much of a look at the tubes.  If the tubes that you can see, have some whitish build up ( corrosion ) on the them.  I would remove the radiator and have a radiator shop remove a tank and have the flues rodded out.

     Remember if any flue, or part of the radiator is plugged or blocked then that part of the radiator is not allowed to cool.

    You do not say anything about the engine blowing out  coolant so I don't think you are leaking compression into the cooling system.  This a common problem, as well as a loose belt and worn pulleys.

Timothy has a very good suggestion if you have a thermal heat gun.

GT&T

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First things first, verify it's actually getting hot. That means checking with an IR thermometer, and making sure your temp guage or light is working as designed.

Getting hot as you describe it is a heat sink effect. The cooling system on a skidsteer is pretty high performance due to the compact nature. A tractor or truck usually only needs to drop the temperature 5-10 degrees between the inlet and outlet. A SS needs a 20 or more degree drop to work, as stated above make sure the radiator is CLEAN. Next make sure your fan, being a caged blower is clean and being driven at full speed. Most of the Cat SS overheating issues I ever diagnosed that weren't head gasket issues, all had to do with the hyd fan not spinning fast enough or a plugged radiator.

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You would be very surprised to see the amount of dirt that will be washed out from a radiator, where it collects in each of the four corners where the fan cannot pull air thru.

I have washed pounds of built up dirt out of them once you remove them and lay they out on the ground and wash from both directions.

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I am curious what its doing also to make it "act like its overheating" ? like mentioned above is it blowing coolant out, or running weird or smells like antifreeze? You should be able to grab a cheap coolant gauge from any auto parts store for cheap. As already mentioned ir gun helps a lot.

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7 hours ago, Art From DeLeon said:

You would be very surprised to see the amount of dirt that will be washed out from a radiator, where it collects in each of the four corners where the fan cannot pull air thru.

I have washed pounds of built up dirt out of them once you remove them and lay they out on the ground and wash from both directions.

X2,  Blow it out and separate the  oil cooler from radiator as the dirt can really pack between them. Then wash the fins with a hose. Check the condition of antifreeze too. If its rusty and funky flush cooling system. Calgon works well for the flush. ir gun will help pinpoint your problem

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1 hour ago, edwardporter1 said:

X2,  Blow it out and separate the  oil cooler from radiator as the dirt can really pack between them. Then wash the fins with a hose. Check the condition of antifreeze too. If its rusty and funky flush cooling system. Calgon works well for the flush. ir gun will help pinpoint your problem

X3.  It will amaze the heck out of you what is in a radiator and how much better they work.  We have my uncles bobcat here and that's on the list.  It needs to be cleaned 

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38 minutes ago, AKwelder said:

X3.  It will amaze the heck out of you what is in a radiator and how much better they work.  We have my uncles bobcat here and that's on the list.  It needs to be cleaned 

As miserable as it sounds take the time to pull rad and pressure wash it, when I first got my pickup it overheated hauling a 8k camper up some hills any temp pulled and washed rad out no more issues.. I spent 45 minutes just cleaning it .

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Are you hitting the paper clip (click to choose files) on the left or the insert other media button when you post?

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