2018 T-Boss overheating, water pump question

[dant849]

This looks to be a pretty common topic and I've had issues with mine overheating since I got it back around the end of 2019. Started running hot again, thermostat was not opening and they sent me a new one. Installed that, burped the system for air all to no avail. Next in line is the water pump to replace, they sent me a water pump and when I got the old one off it was not turning freely to say the least so I'm thinking that could have been my problem. My issue now is getting the slot in the water pump shaft to line up with the tab inside the engine of the machine. Any tricks to doing this? Thanks in advance

[T-boss 410]

What make is the engine? A member here (Joe Breaux) had some overheating issues with his Massimo. He managed to override the thermostat and has the cooling fan running constantly, as long as the engine is running. Fixed his problem. I have a 2019 T-Boss 410, but haven't had any such issue (yet), knock on wood! I understand that Massimo had some overheating issues with a certain make of engine, and they switched to another engine maker. 

[Joe Breaux]

If you keep getting air in the cooling system, its probably not just the pump, your head gasket and maybe your head is blown.. Massimo is famous for overheating 

[T-boss 410]

Am I correct in assuming that, per earlier conversations, that it's the Hisun engines that are prone to overheating?

[Joe Breaux]

I think its pretty common in all Massimo machines.. the cooling systems are poorly designed . The HISUN had other issues as well as overheating, thats what prompted Massimo to discontinue them and use Linhai engines .. Dont seem any better

[T-boss 410]

Well.....that don't make me feel good! What is the problem within the cooling system?

[Joe Breaux]

The engines are factory set on fan switch to run really hot.. the engines are not capable of withstanding those high temps . Thats my experience anyway.. I have brought mine down 40 -50 degrees or so and it seems to be much better.. 220 degrees is just too hot in my climate. Maybe in canada its OK.. MAYBE..  The fan is capable of keeping it cool if you bypass that switch and run 100%. .mine now stays cool and I dont seem to have any more problem.  Plus I dont have the massive heat coming up behind my seat now. 

[T-boss 410]

So, there is no known way to reprogram the ECU to lower the temp for the fan to kick on? There's lots of programmers out there in the automotive industry that will accomplish that. Could it be set at that temp for environmental reasons, ad the automakers did?

[Joe Breaux]

Dont know.. My Mechanic did not know  of any either.. he showed me how hot these run and recommended full fan operation.    Hes the only repair shop within 200 miles of me that will even work on Massimo machines  so .....  IT WORKED!  Thats my only concern.. you can try to find something online maybe but I doubt theres any device for Massimos ... I know if you let it run at factory set temps , you will never keep head gaskets ...   Massimo  admitted as much to me on phone. Mine even cracked the head and had to be replaced.. If your concern is environmental pollution from yours, maybe UTVs are not for you? They are off-road vehicles, emission stanards are much different than your daily driver .. Spark suppression is a much bigger concern in the woods that can burn 

[T-boss 410]

I think you misunderstood me. The automakers have set up the cooling systems in passenger cars and trucks to run hotter than I would like, with the reason being it's more fuel efficient. I was just curious if maybe that was the reason that Hisun programmed the ECU to fire up the fan at such a high temperature. 

Have you thought about the possibility of the fan motor burning out from running constantly? Is that a part that can be obtained from other sources than Massimo?

I wonder what other makes of UTV's have their fan set to run at? I know there are programmers out there for other makes of UTV's, but I haven't found anything for the Massimo. 

[dant849]

my radiator never gets hot so I don't understand how the fan can make a difference. The fan cools the radiator, right? I don't believe that the water ever circulates through my engine or the radiator and the hoses would warm up, wouldn't they?

[Joe Breaux]

The reason your radiator is not hot is because you have steam/ air blocking the system and water is NOT CIRCULATING.. So theres no hot water to cool.. radiator isnt hot, But your engine is boiling .. If you bleed the air out of all vent screws, the water will move again  if your pump is good but the air leaking into system from blown head gasket will block it again in just a couple miles .  I just went thru all that and so have  a lot of us.

[Joe Breaux]

11 hours ago, T-boss 410 said:

I think you misunderstood me. The automakers have set up the cooling systems in passenger cars and trucks to run hotter than I would like, with the reason being it's more fuel efficient. I was just curious if maybe that was the reason that Hisun programmed the ECU to fire up the fan at such a high temperature. 

Have you thought about the possibility of the fan motor burning out from running constantly? Is that a part that can be obtained from other sources than Massimo?

I wonder what other makes of UTV's have their fan set to run at? I know there are programmers out there for other makes of UTV's, but I haven't found anything for the Massimo. 

My mechanic says he has done dozens and the fans run for years at 100%.. He says because Masimo didnt build them..lol

[T-boss 410]

I hope this is something you don't already know, and if it is, I apologize. I had sent an email to Brandon Beaver, a tech for Massimo, asking about the ECU programming. According to him, the ECU isn't responsible for when the fan comes on, but it's a thermoswitch that's mounted on the radiator. He says that a thermoswitch that is rated at a lower temp can be purchased (although he didn't mention where) to replace the OEM one. He also advised the the temp is set at 215-220, and that Yamaha has theirs set at 217, and that range is normal in the powersports industry.

Hope this helps, but if it doesn't, just ignore it. I was just trying to give an alternative to the fan fix.

[dant849]

3 hours ago, Joe Breaux said:

The reason your radiator is not hot is because you have steam/ air blocking the system and water is NOT CIRCULATING.. So theres no hot water to cool.. radiator isnt hot, But your engine is boiling .. If you bleed the air out of all vent screws, the water will move again  if your pump is good but the air leaking into system from blown head gasket will block it again in just a couple miles .  I just went thru all that and so have  a lot of us.

thanks Joe... I know that there's a vent screw at the bottom of the water pump. Aside from taking the cap off of the radiator and the Overflow Reservoir are there other places that air can be bled?

[Joe Breaux]

It may be normal for quality built engines from HONDA or Yamaha  but it cooks cheap chinese heads and gaskets.. I told you of my experiences with Massimo. I told you what an experienced Massimo mechanic recomends.. I can do do more ... But I can tell you if you let it run 220* plus, [ because it will go to 230-240* with factory settings  on hot days  ]you will be pulling heads regularly.. Mine fried the first HEAD AND HEAD GASKET  at 250 miles ..   You paid for it, so you can choose to do what you want.. I was just giving you benefit of my experiences and several others on here as well where I live and the dozens of Massimos that my mechanic has repaired ... besides if those temps were safe for HISUN engines, WHY DID MASSIMO DISCONTINUE USE of them completely  and tell me on phone how they are plagued with overheating....anyway  ??   Good Luck..   If you want to attempt Head Gasket repair yourself, there is a video on YOUTUBE of how to . Be aware it is a chain drive overhead cam   with flyweight timing advance mechanism on cam assembly .. You can do it in the frame 

[Joe Breaux]

15 minutes ago, dant849 said:

thanks Joe... I know that there's a vent screw at the bottom of the water pump. Aside from taking the cap off of the radiator and the Overflow Reservoir are there other places that air can be bled?

there is another vent on the top of the head , you may have to do it several times.. but if you have air, your head gasket is toast, and water will stop circulating in a few miles  again ... have you checked for water in your oil? 

[T-boss 410]

Gees, I'm just passing along some information that may or may not be useful for another Massimo owner. Maybe that could save them from the situation that you went through. Replacing the thermoswitch would (I assume) be much less expensive than a new head and gasket, along with the labor. 

Just trying to do some good here. 

[dant849]

40 minutes ago, T-boss 410 said:

I hope this is something you don't already know, and if it is, I apologize. I had sent an email to Brandon Beaver, a tech for Massimo, asking about the ECU programming. According to him, the ECU isn't responsible for when the fan comes on, but it's a thermoswitch that's mounted on the radiator. He says that a thermoswitch that is rated at a lower temp can be purchased (although he didn't mention where) to replace the OEM one. He also advised the the temp is set at 215-220, and that Yamaha has theirs set at 217, and that range is normal in the powersports industry.

Hope this helps, but if it doesn't, just ignore it. I was just trying to give an alternative to the fan fix.

I appreciate your input. I replaced that switch back several months ago when I first got the machine and it was running hot then. Turned out to be a stuck thermostat that time. The fan works when I put 12 volts to it so I believe what is happening is that the water in the radiator is not warming up therefore the fan is not coming on. Put a new water pump in over the weekend. I guess I'll try to burp it again

[dant849]

24 minutes ago, Joe Breaux said:

there is another vent on the top of the head , you may have to do it several times.. but if you have air, your head gasket is toast, and water will stop circulating in a few miles  again ... have you checked for water in your oil? 

Thanks for your reply, no water in the oil. But there was oil in the coolant. I found out the hard way that when you pull the water pump that you also drain the oil as they seem to share common seal. at any rate, the oil looks good. Can you describe the process that you go through to relieve the system of air in detail? I appreciate it

[Joe Breaux]

33 minutes ago, T-boss 410 said:

Gees, I'm just passing along some information that may or may not be useful for another Massimo owner. Maybe that could save them from the situation that you went through. Replacing the thermoswitch would (I assume) be much less expensive than a new head and gasket, along with the labor. 

Just trying to do some good here. 

 bypassing that switch does a lot of good, ...brings down excessive temps, saves your engine and costs ABSOLUTELY  nothing.. thats seems like a good thing to me .. Good Luck on yours .. If you can get these to run more than a few miles, they are a lot of fun..  Mine does well in mudholes. My Neighbor has a Kawasaki Mule.. I went thru a deep mudfilled wash out, he followed  and he got stuck .. I PULLED HIM OUT! .. He was not happy.. lol

[T-boss 410]

I don't remember if I asked you (the memory is the first thing to go), but how did you wire in the bypass?

[Joe Breaux]

It could not be easier.. Unplug the black plug -in  from switch on the radiator . put a short jumper wire  from  one side of plug to other.. the switch just interupts that wire.  Tape it up .. It will only run if key is on.. 

[T-boss 410]

So, you just leave the thermoswitch in the radiator? I take it you used enough tape to basically waterproof it?

Thanks 

[dant849]

2 hours ago, T-boss 410 said:

So, you just leave the thermoswitch in the radiator? I take it you used enough tape to basically waterproof it?

Thanks 

So I think I got lucky and got all the air out. It's circulating now and I jumped the fan so it would run whenever the key is on to help keep it cool. Currently running a cool two to three bars out of five.  Thanks for the help!

[Joe Breaux]

2 hours ago, T-boss 410 said:

So, you just leave the thermoswitch in the radiator? I take it you used enough tape to basically waterproof it?

Thanks 

Yep.. thats it.. tape it good to keep water out in rain and such.. hit the trails and enjoy...... if your head gasket isnt already leaking.. you will know within a few miles ....

[Joe Breaux]

20 minutes ago, dant849 said:

So I think I got lucky and got all the air out. It's circulating now and I jumped the fan so it would run whenever the key is on to help keep it cool. Currently running a cool two to three bars out of five.  Thanks for the help!

Hope it doesnt airlock again.. if it does, its a head gasket leak.. only replacing it will fix that .. But keeping those engine temps down prevents future blown gaskets 

[T-boss 410]

Did you change your thermostat? Where did you find one?

[Joe Breaux]

not using a thermostat 

[T-boss 410]

Would it need one if it's not supplying heat to the cab? I don't see the need for one unless it's used for heat.