2015 Brute Force 750 Overheating

[LBZ]

Buddy’s quad started overheating at 300km.
No the rad is not plugged with mud. It’s like new. Rad is full. Overflow tank is up to level.

At idle, The fan comes on at about 165F and never shuts off after that and the temp never drops below that either. It maintains 165-170F at idle. When you idle it up it starts slowly gaining temp with about a 6 degree drop across the radiator but never drops. Fan running steady the whole time. Any idea’s?

 

[armascott]

Could be a faulty thermostat

 

[LBZ]

Could be a faulty thermostat

It heats up evenly across the thermostat after about 160F and only has a 6 degree drop from the thermostat to the water pump inlet so I believe it’s opening.

 

[sirkdev]

Air lock?

 

[Stg2Suby]

I was thinking air lock as well, weird it would happen at 300km though.. Water pump/impeller failure maybe?

 

[LBZ]

I don’t believe it’s a circulation issue because I can check it at the outlet of the thermostat and inlet to the water pump (as far apart as you can be as far as flow goes) and once the thermostat opens they both heat up almost evenly but a couple degrees apart.

Also slow moving coolant would cool off a lot more across the radiator or the rad temp itself would be substantially less than closer to the engine. Especially after the fan was running.

As far as an air lock it’s possible but doubtful as it’s never used coolant to require top ups from low coolant levels and the system has never been opened. That and it just started doing it around 280km mid ride on dry trails. The fan has always stayed on once it comes on though right from new.

I’m baffled by this one. Initially I thought it would be a bad sensor or something but it legit is getting hot. It’s almost like the rad/fan combo aren’t effective/efficient enough to keep heat under control under load or cool it off at idle even. It does look like a cheap cheesy rad in it compared to other machines.

 

[doorfx]

Pressure test the cap or just replace it.

 

[LBZ]

Already replaced last year. First thing we tried.

 

[neilsleder]

Check the veins in the rad to see if they are swollen. I know can ams were bad for that.

 

[250mark1]

maybe check the overflow bottle it might be like the can-am were a few years back under the overflow bottle cap was plug with a small hole in it that you needed to make a larger hole in

 

[whoDEANie]

Sure sounds like a bad or plugged rad or an air lock. Elevate the front of the machine a bit, remove the rad cap, and run it to full temp. Once at full temp, blurp the throttle for a few minutes and replace coolant as needed. The whole process should take you a good 20+ minutes. Might also be worth pulling the rad just to see how clean it actually is - most people are surprised by what they find.

 

[LBZ]

Already done all those things except the overflow tank and pull the rad. Will have to check the cap on the tank. The fluid is coming up though in the bottle the normal amount as per the marks on it.

The rad is super clean I assure you. If it needs to be cleaner than it is to ride in the bush and not overheat then this machine can never leave the pavement lol. There is no shroud or anything around it. Just a fan on the back and a cheezy screen on the front.

We did the air lock thing. Got no bubbles. Didn’t have to add any coolant after. It’s good. I wonder too though if maybe something came apart in the rad and is blocking some of the flow through it. It’s not a common designed rad as it goes in and out on the same side, but the lower hose isn’t at the bottom, it’s almost in the middle.

 

[the_real_wild1]

Put some clear hose in line and see if the coolant is moving. Are you sure it is actually overheating?

 

[tex78]

This is the answer Dale, extra rad with toggle switch on fan

Most of the time the extra capacity, made quad Run Better, winch worked better as lower fan was not on all the time

 

[the_real_wild1]

The other thing to check if you haven’t is the coolant strength.

 

[LBZ]

Put some clear hose in line and see if the coolant is moving. Are you sure it is actually overheating?

You can see it circulating when you pull the cap. If it wasn’t circulating it wouldn’t heat up evenly when comparing the thermostat outlet to the water pump inlet. We never let it run until the over temp light came on but just reving it up a bit I watched the temp climb steadily up to 200 before we shut it down so I’m sure it will just keep going till the over temp light comes on. Fan running steady the whole time.

 

[LBZ]

This is the answer Dale, extra rad with toggle switch on fan

Most of the time the extra capacity, made quad Run Better, winch worked better as lower fan was not on all the time //uploads.tapatalk-cdn.com/20180625/4821b70f76408fea8bfcb8991979bf9f.jpg

Ya we talked about that. I think he will trade it off on something else before he does something like that though lol. Doesn’t want to lose the front rack.

 

[LBZ]

The other thing to check if you haven’t is the coolant strength.

-35 Celsius

 

[lilduke]

Low on oil maybe? An oil cooler would help.

 

[acesup800]

Guys, pretty sure he isn't looking for things to help make it run cooler. Something is obviously broken or wrong and needs repair.