Overheating Possibility

geohorn

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When I got my new-to-me 2015 X900 home I found a puddle of antifreeze under it directly beneath the drivers seat. It was a loose hose clamp where a rubber coolant hose connected to a metal tube.
Removed the clamp and caught the coolant in a pan, cleaned up the metal tubing light corrosions with a wire brush, cleaned the inside area where the hose mated and re-clamped it nice and tight.
Poured the drained coolant directly back into the radiator, not touching the reservoir which had about 3/4 full indication.
Let the wife try driving it and within a hundred yards it gave us overheat warnings. We turned around and returned to the house and shut 'er down.
Raising the hood I observed the reservoir to be empty.
Using a welder's glove I opened the radiatior cap and the radiator also appeared empty. ??? Made no sense... the same amount drained was returned... but now both the radiator tank AND the reservoir are empty?

I mixed up some 50/50 and serviced the radiator tank (took about a quart) and filled the reservoir (about another quart) and ran it …. everything has been operating normally ever since now, for about a month.... and the reservoir has remained full.

Today I was digging around and found HIDDEN (stuffed) within the left, rear ROPS, at the "box" just forward of the left cargo-release-lever a 3/8" rubber tube with a plastic-capped "vent" valve. It was not visible at all previously. The rubber line leads down beneath the cargo box to the thermostat housing on the top/front of the engine. Looking at the Messicks parts webpage... YEP! THA'R SHE BLOWS!... ref: A38000, item 70, "Air Bleeder Hose".
https://www.messicks.com/ku/90482
I'm reminded of the days when I was a Toyota Tech back in the early '70s. If the coolant was drained (even a little bit) the thermostat had to be "vented" before it was safe to run the engine. A "bubble" of air would be entrapped in the head and surrounding the thermostat. When the engine was started, the thermostat could not sense the coolant temperature because it was not submerged in coolant. Not until the engine was extremely over-heated would the internal steam of the hot coolant finally heat-soak the thermostat and (if lucky) it would open and allow coolant to flow through the engine.
If unlucky.... it'd be too late and the head gasket would blow … and the head may warp or crack.

Let my discovery be a heads-up to everyone... If you drain your coolant, be certain when refilling to have that breather hose valve OPEN to allow the air to escape the thermostat housing. After the radiatior, engine, and reservoir are all filled... THEN and ONLY THEN, close the breather hose valve.
Don't drive around until the engine has fully warmed up and stabilized, and the coolant level re-checked in order to avoid being away with an overheated RTV and no coolant or tools or gloves to deal with it.

(And for goodness sakes don't open a hot radiator cap willy-nilly or add cold coolant to a hot engine.) Hope this helps.
 

aurthuritis

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Dang! a Yota Bota Tech. my 2015 X1100C has the bleed hose attached to the to the back of the cab. so does the 07 i think. glad everything is OK. I had an FJ 55 a 60 and a 62. then i drove a Rover IIA for ever and now the wife and daughter have series 100 cruisers.
 

geohorn

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My 2006 RTV900 does not have this line.
?

It doesn't show up in the General Purpose parts illustrations.

This may not mean you're off the hook... it may only mean you have a more difficult time bleeding the air out of the system to avoid overheating when changing antifreeze. Some engines with which I'm familiar require the thermostate housing to be "cracked open" to allow air to excape until coolant aqpears to have filled the cavity.
 

geohorn

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Don't specifically know about the earlier RTVs but some engines have a "bleed screw" installed in heads, on thermostat housings, etc. to provide for this. It's commonly an "allen" plug in an upper radiator-hose elbow.
Here's a pic of one in a Jeep.
 

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v10rick

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It doesn't show up in the General Purpose parts illustrations.

This may not mean you're off the hook... it may only mean you have a more difficult time bleeding the air out of the system to avoid overheating when changing antifreeze. Some engines with which I'm familiar require the thermostate housing to be "cracked open" to allow air to excape until coolant aqpears to have filled the cavity.

The antifreeze was flushed when I replaced the head. It has been about a year but I don't recall an issue with bleeding air out of the system.

Maybe beginners luck?
 

geohorn

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If you learned to replace the antifreeze from an "old timer" you may have enjoyed good luck.

In earlier designs it was common to drain and refill radiators with the CAP OFF during the subsequent engine-run to allow the coolant to circulate at atmospheric pressure. This assisted in evacuating captured air within the system because the coolant would "back-flow" via the upper radiator hose and sit on top of the thermostat, bubble thru the thermostat vent-hole, and convey heat to the thermostat encouraging it to open early in the process.

With later "reservoir" designs that method has largely been relegated to history in maintenance manuals and trade-school training. Vents are usually designed into heads, thermostat housings, etc. for the tech to use.

(In my own error, I did not see the breather-hose because someone had not attached it to the frame as the parts manuals illustrate....but had stuffed it inside the lower ROPS tubing where it lay hidden. The engine is not readily seen because of the cargo-box/seats and the hose leading from the thermostat appeared to go forward where it disappeared, so I didn't recognize it's utility, and both the radiator tank and the reservoir were completely full when I returned the drained coolant to the tank. In hindsight, it must have been a system that had been leaking fluid for the previous owner who remained silent about the problem, therefore the system was likely devoid of coolant and only the tank/reservoir were full, likely by the seller to dispel suspicion of the used equipment. I accepted the seller's praise of the unit and did not properly inspect the RTV prior to purchase in the on-going rain downpour. My bad.)

Hope this helps.
 

shinnery

Active member
My '06 RTV900 does not have this relief hose, I have done enough work in that area and would have seen it. I bought it over egag out of Arizona and when it arrived I soon realized it had an incomplete cooling system.
The spigot on the side of the thermostat housing that the water pump bypass hose is supposed to connect to was missing, broken off. I got a pipe tap, 1/8 in. pipe (if I remember correctly) and it fit down into the hole in the housing a ways. I threaded the housing and bought a short brass nipple and screwed it into the housing with sealer. Clamped the bypass hose to the nipple and had a complete system, I thought, until I realized the water pump was leaking at the shaft seal.
I bought a pump from another vendor on egag and installed it. When I pulled the old pump out I found it had NO fins left on the impeller, it wouldn't have pumped much coolant if it had not been leaking. I cannot remember if I replaced the thermostat while having all this fun or not. But there was no relief hose in the way at any time.
Bryce
 

Big O

New member
Overheating on 1140

My 1140 proceeded to closely approach the red zone for a few days then overheated. The following steps were taken to solve the problem:
1. Cleaned spark plug arrester which helped some.
2. Backflushed with Prestone four times and refilled system which helped a lot.
3. Removed my secondary 16 mesh/inch screen from existing screen on radiator which helped a lot more.
4. Cleaned primary screen on radiator and radiator with compressed air front and back which helped a little.
5. Flushed front and back of radiator with water which seemed to solved the problem but temp reading stayed up then
6. Removing the radiator from the fan, from the vehicle, and front and back flushing with water did the job. Easy job on a 1140.

I think that the removal step will be a yearly maintenance chore since the fan in place prevents one from totally cleaning the fins. Hope this helps 1140 people.
 

Big O

New member
Ultimately Solving the Overheating Problem 1140

Thought I had solved my problem thru the previous listed six steps but it reoccurred. Hopefully the problem has been solved by using an aspirin to hold open a new thermostat replacement on my 1140. I presume many on this forum are well aware of using this technique upon refilling the system to alleviate an air problem. A side note that may potentially help others is what that a Kubota repair shop person told me. I queried him on the overheating issue and he said that the internals tubes are glued together in the radiator. A localized plugging condition can arise when the glue material reacts with the water/antifreeze. This will be seen and confirmed by looking into the radiator and observing a white material at the top. For what it is worth.
 

Big O

New member
Thermostat With Double Opposing Holes

This same Kubota repair person suggested drillilling opposing holes on the face of the thermostat to prevent an air lock. Aurthritis was spot on.
 
A trick I was shown many years ago that has never failed me, ensure the radiator is higher that any other part of the cooling system. Drive the front wheels up on ramps, then fill. Air will always try to find an exit at the highest point in the system. The other option, go to HF and buy a vacuum cooling system fill tool. It uses shop air to create a vacuum in the cooling system and ‘sucks’ the proper amount of coolant into and throughout the system. It’s fast and easy. I use a Snap-On I purchased many years ago when I made a living wrenching on European High Line vehicles. Many cars use the smaller radiator caps these days. So finding a proper adapter should be easy as well.
Humbly submitted for your reading pleasure....
 
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