460/560 thermostat air locked.

Jazz Hands · Jan 31, 2011

Are the 460/560 gas engines notorious for air locking the thermostat when you replace the coolant? Mine boiled over on me this weekend after running it for only 5-10 minutes or so. I hope I didn"t do any damage, I shut it off and started it every two minutes or so for 10-15 seconds "till it cooled down. Then, thinking back 4-5 years my old 560 did the same thing on me when I replaced coolant on it after replacing a hose.

And as long as we"re on the subject, am I the only person that drills two small holes in a thermostat when they replace the it? I"ve never figured out why they don"t have them from the factory. What is the sense in making them air tight or nearly so.

soybeanjoe · Jan 31, 2011

I had a 756 gas do that a couple years ago with me when I replaced the antifreeze.

Red Dave · Jan 31, 2011

I've done the same thing. Just a small one, 1/8 inch is enough.

I started it after I had a Jeep thermostat get air locked for me

Brownie 450 · Jan 31, 2011

Our 560 Diesel had a system vent up by the thermostat housing that took care of all air in the engine up to just below the thermostat. Maybe yours has been taken off. It looked like a wing nut with a hole in the center.

1970-1655 · Jan 31, 2011

Old auto shop teacher showed us that back a few years. (1966) I have done that on every thermostat I have changed with no problems. 3/32" or 1/8" is all I would use.

TractormanNC · Jan 31, 2011

I drill em too. one 3/32 hole

656 with D282 should be the about the same as your 560, has a vent on the side of the thermostat housing.

redgems · Jan 31, 2011

Thermostat air locked when I replaced anti-freeze on my SMTA last winter. By the time I shut down I had melted a portion of piston to the rings on 1st & second cylinders. I never heard of drilling hole in thermo. Please tell me where on thermo you place the hole. Tony

sflem849 · Feb 1, 2011

...And as long as we"re on the subject, am I the only person that drills two small holes in a thermostat when they replace the it? I"ve never figured out why they don"t have them from the factory. What is the sense in making them air tight or nearly so.

So you drilled the holes in the tstat and it still air locked?

pete 23 · Feb 1, 2011

A lot of thermostats come with a small hole, but not 1/8th inch . More like .050 or less. The 560 will air lock but the bleeder valve discussed here always has released the air for me. On other models I often loosen the temp gauge to let air escape but this is normally on an engine I have just assembled so it is easy to loosen. On the M and H style thermostats it is pretty hard to get an air lock unless the wrong thermostat is being used. The correct ones don't seal all that well in the housing. Over the years some automotive style thermostats have been installed in them and they do not allow the by pass system to function correctly. Some auto stores still sell the wrong ones I think.

62champ · Feb 2, 2011

My auto tech teacher in high school always had us do something with each thermo we put in to guarantee there would be no air lock.

We would tear a small piece off the edge of one of the tabs from the thermo box and them force the thermo open and wedge it in. This allowed air to escape and when it opened up the first time the small piece of cardboard would simple disintegrate in the coolant.

Good luck.

460/560 thermostat air locked.

Jazz Hands

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soybeanjoe

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Red Dave

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Brownie 450

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1970-1655

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TractormanNC

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redgems

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sflem849

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pete 23

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62champ

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