Coleman UTV 400 Overheating

[Rey Ximenes]

OK, here's the mystery of the day. I was using the UTV the other day and the idiot light came on that said it was overheating. I immediately shut down and checked the coolant. No coolant! I refilled the overflow reservoir and the radiator and all was fine. 2 days later the light is on again. I rechecked the radiator and it was again empty? Bone dry? Now, here's the weird part, There is no coolant anywhere on the floor below the vehicle. I can't even see any on the frame. I have it up on the lift and am getting ready to start tearing into the bottom "skid plate" to see if the leak is in the hoses there. Any suggestions as to where to start? I have yet to begin and I am already baffled!

[Rey Ximenes]

BTW, Coleman UTV 400

[aefron88]

Before you tear it apart...they have history of trapping air in the lines. I would go ahead and fill the radiator and run it.

There's a bleeder port on the driver side of the engine where the coolant hose goes in. Crack the little plug on the fitting to bleed the air while running. Once it's all bled fill it up to the top again.

Once you bleed the air out let us know if it's still burning coolant and we'll go from there.

[Rey Ximenes]

I'll try that before going any further. Thx!

[Rey Ximenes]

OK, I refilled the radiator and the reservoir and bled the system as suggested and that worked great! Unfortunately the idiot light came on again after 10-15 min and I think I realized then what the problem might be. The fan never did come on. Not at all. Perhaps a broken temp sensor or a bad fan? Relay? The water did circulate when I filled the radiator so the water pump must be OK

[aefron88]

Rey, here is the relevant section from the service manual. I skipped the ignition switch and battery parts since we know it runs. If I had to place a bet I would bet on the thermal switch on the rad being disconnected or failed.

[Rey Ximenes]

That is awesome. Can't thank you enough. I'll get back as soon as I can check this out. Wish me luck. I'm going in. Hopefully I can get parts! Is it possible to get a service manual?

[aefron88]

Service manuals are in the download section of this website.

Parts are available, worst case you could just jump it out so the fan stays on when the key is on.

[aefron88]

Just digging around on the machine since I haven't seen the sensor before I believe it is on the drivers side just above the coolant hose, on the rear of the radiator.

It has a rubber cover zip tied over it.

Hopefully your hands are smaller than mine 😂 it doesn't look all that fun to get to.

[Rey Ximenes]

I was looking in the download section and can't find the manual. Is it the same as the Hisun 400?

[aefron88]

Yes

[Rey Ximenes]

I got the front compartment opened up somewhat, and running 12 V to the fan showed that it ran smoothly. I could find no fuses fried but I am not exactly which one powered it. I got the thermistor out (not too bad really!). I could run the test on the thermistor but I think it might be easier to just get a new one. They are apparently delicate so I'm hoping this is the problem. BTW, for future reference, the fuse box is under the seat. The manual doesn't really say where it is, or I just missed where it did, but there is a YouTube video out there that clearly shows it under the hood by the regulator in a Hisun, but in the Coleman version it is on the driver's side to the front, under the seat. 

I will order the thermistor and hopefully can get that sometime soon. Thanks for your help. I'll get back as soon as I get the part in. Hopefully this can help someone else too.

[aefron88]

Glad you got it apart. You can do a rough test by just making sure it's open between the two pins at room temp and closed at higher temp (which would turn the fan on) more than likely it has failed if the fan is running well.

The fuse box is under the seat on all 400s. The 550s/750s etc it's under the hood. The Hisun produced how to videos mostly cover the 550 and 250 models, and there are a few changes.

[Rey Ximenes]

OK, a little follow up. I ordered all the parts but none have arrived as of this time. Closer exam of the plug to the thermistor revealed heat damage and testing of the thermistor showed it to be "open" and not to close at running temp. It is fried! I fashioned a jumper wire across the plug wires on the thermistor that can be easily removed once I get the parts. 😬The fan now runs whenever the power is on and it seems to be running smoothly. It hasn't overheated yet. The coolant fill went ok but it kept getting air in the circuit. Curiously, keeping the front end of the UTV up on a jack raised the front end and made this easier to do without getting the air. I did still have to use the air bleed screw at the motor. 

[stu]

Remove inner fender 4 screws to get to radiator coolant FAN switch. Greasing the front u joint is a woolly burger.

[stu]

Same thing here.  Started over heating January 3rd, 2023. 4 screws remove inner fender for access to cooling switch then easy peasy. Greasing front u joint is another matter. 

[stu]

The outfitter 400 thermostat switch is 16mm not 18mm. So ask when ordering

[Dave K]

On 12/31/2022 at 7:02 AM, Rey Ximenes said:

OK, a little follow up. I ordered all the parts but none have arrived as of this time. Closer exam of the plug to the thermistor revealed heat damage and testing of the thermistor showed it to be "open" and not to close at running temp. It is fried! I fashioned a jumper wire across the plug wires on the thermistor that can be easily removed once I get the parts. 😬The fan now runs whenever the power is on and it seems to be running smoothly. It hasn't overheated yet. The coolant fill went ok but it kept getting air in the circuit. Curiously, keeping the front end of the UTV up on a jack raised the front end and made this easier to do without getting the air. I did still have to use the air bleed screw at the motor. 

 

Edited January 26, 2023 by Dave K
Please delete this as I am new and didn't mean to copy. Just meant to reply to his comment.

[Dave K]

I am new here on the forum so wanted to thank you all for posting this info. It is helpful as I have 2 Coleman UT400's (2020 & 2021 models) Found similar issues as you Ray. So, this is what I've found so far. The overheating/temp light is on. No leaks and isn't low on coolant. Fan is not turning on, unless I jump 12 volts to it then works fine. All fuses in fuse box under seat are working and not blown. The temp sensor located on engine seems to have an open when doing an OLM test with meter. Tested the other SXS's known good one and got an OLM reading. So, I swapped them and didn't make a change on either SXS. Back to the drawing board until now. Ill check the thermistor switch soon and get back to you on my results. In the meantime, Ray did your parts come in? and any progress or updates? Also unrelated I believe... both horns on the same vehicle don't work. Haven't got far yet on testing them but has voltage to them from switch, but not sure of ground. Figured I'd ask if anyone had any info while on here. I'll be doing more diagnosis soon and will update if anything changes. Just thought it was strange both horns are inoperable. Thanks again for your advice. 

[Rey Ximenes]

Some of the parts came in but not all. I did get the thermistor and that is all working for now but I am not sure how long it will last. The plug got partly melted in the original overheat and it appears to be a bit fragile so we will see. I am not sure how to get another plug as I think it is listed as a wiring harness! I have never been able to actually contact anyone at Coleman so I don't know. I do know that if all else fails I can just put the jumper back on. BTW, my horn is working.

[Dave K]

On 1/25/2023 at 10:19 PM, Dave K said:

I am new here on the forum so wanted to thank you all for posting this info. It is helpful as I have 2 Coleman UT400's (2020 & 2021 models) Found similar issues as you Ray. So, this is what I've found so far. The overheating/temp light is on. No leaks and isn't low on coolant. Fan is not turning on, unless I jump 12 volts to it then works fine. All fuses in fuse box under seat are working and not blown. The temp sensor located on engine seems to have an open when doing an OLM test with meter. Tested the other SXS's known good one and got an OLM reading. So, I swapped them and didn't make a change on either SXS. Back to the drawing board until now. Ill check the thermistor switch soon and get back to you on my results. In the meantime, Ray did your parts come in? and any progress or updates? Also unrelated I believe... both horns on the same vehicle don't work. Haven't got far yet on testing them but has voltage to them from switch, but not sure of ground. Figured I'd ask if anyone had any info while on here. I'll be doing more diagnosis soon and will update if anything changes. Just thought it was strange both horns are inoperable. Thanks again for your advice. 

 

[Dave K]

Update I finally had some time and checked into the overheating issue. Found when I removed the radiator temp switch from sensor, and went to use a jumper wire to test fan. The wires in the connector popped out and were not going in, and or staying. So bent tabs back and was able to get wires to stay in for now. The fan works as you said with key on after jumping it. Did some researching and found a harness and rad temp sensor on Amazon. So just ordered and will let you guys know how it works out. Sorry it took a while to respond. Now to the shifter linkage adjustments for popping out of gear.

 

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Radiator, Sensor, Water, Temp, Fan Switch,UTV,400,500,700,800,Hisun,Massimo,Tsc,MSU

Brand: thitherwk

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Brand	Thitherwk
Switch Type	Temperature Switch
Mounting Type	Wall Mount
Unit Count	1 Count
Number of Items	1

 

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About this item

• Radiator, Sensor, Water, Temp, Fan Switch,UTV,400,500,700,800,Hisun,Massimo,Tsc,Msu

[Ron H]

You guys left me hanging, was it the sensor?  I am wondering if the issue is also not the thermostat at the engine.