Radiator hose blew - advice desired.

[farmerj]

Hi Guys,

Great ride on Sunday, until my radiator hose blew off, right below the thermostat. I'm glad it was only a 15 minute push back to the pickup. I can't have this happen 20 miles out!

90 hrs. and I've never overheated. I wondered if the thermostat went bad, but tested it on the stovetop and it works perfectly. Can anything else cause a buildup of pressure? Or do the OEM hose clamps loosen over time? In theory, the radiator cap should release pressure before blowing a hose if I'm overheating, right?

I've searched and read a lot of threads, but find conflicting advice. Do I try again with new clamps? Ditch the thermostat?

I want to do something different to at least feel like I might have the problem solved.

Thanks for your thoughts.

Jeff

 

[Gasser Nate]

It is those crappy clamps, if memory serves there is not much of a lip on the housing to help hold the hose and clamp on. I would just get rid of the thermostat. Just another failure point and not needed on an enduro bike.

 

[webmaster]

I notice you have an '05 and an '18 in your signature.

While you are getting things back together... I would check the water pump impeller. Older ones are plastic/phenolic that can erode/degrade over time. This is particularly true if overheated.

An alloy one will flow much better.

jeff

 

[(F5)]

There is another thing that can cause pressure build up. Perhaps a leaking head oring?

 

[swazi_matt]

take the other points into account, but you are right, the cap should be the first place to release pressure. If the cap is fine then it means your radiator went off at lower than max operating pressure and sounds like a poor grip on the thermostat connection. The OEM clamps only have one tightness setting and probably rely on the bulge in the connection to stay on. So if the thermostat only has a slight bulge it may be better to use a jubilee clamp that you can make tighter or if you are not a snow rider i would just ditch the thermostat and have a single hose (GG do make these without thermostat)

 

[farmerj]

I notice you have an '05 and an '18 in your signature.

While you are getting things back together... I would check the water pump impeller. Older ones are plastic/phenolic that can erode/degrade over time. This is particularly true if overheated.

An alloy one will flow much better.

jeff

Good catch Jeff, this is on the '18. I do have an alloy impeller that came with the 2005, so probably time to install it!

The '05 doesn't get as much ride time as the '18, but is still fun to get out once in a while and compare.

I will assume that the '18 has an alloy impeller unless someone tells me otherwise.

 

[farmerj]

Thanks for all of the ideas, guys, you've given me a direction to go that helps my confidence. I'll get some new clamps and may ditch the thermostat.

Is a thermostat usually "good or not"? Or can it start to open too early or fail and not open at all?

I do ride in the snow once/twice/yr. - and have never considered the problem of an engine running too cold (vs. too hot). What happens in that case? Too cold makes the tolerances too tight?

Thanks,

Jeff

 

[Gasser Nate]

Thanks for all of the ideas, guys, you've given me a direction to go that helps my confidence. I'll get some new clamps and may ditch the thermostat.

Is a thermostat usually "good or not"? Or can it start to open too early or fail and not open at all?

I do ride in the snow once/twice/yr. - and have never considered the problem of an engine running too cold (vs. too hot). What happens in that case? Too cold makes the tolerances too tight?

Thanks,

Jeff

Just a longer warm up time without the thermostat Jeff. Nothing a little due diligence cannot overcome.

 

[farmerj]

Thanks Nate - after today's ride, I'm going to replace it with a temperature sensor. I used quality clamps - and it blew off again! I'm just glad it was a mostly downhill coast back to the rig!

Jeff

 

[(F5)]

So run your bike when it's back together with the rad cap off. If it starts to force its way out with any vigor then you are replacing head oring.

 

[swazi_matt]

Thanks Nate - after today's ride, I'm going to replace it with a temperature sensor. I used quality clamps - and it blew off again! I'm just glad it was a mostly downhill coast back to the rig!

Jeff

small chance there is an air lock in the system. when you fill up the coolant have the bike running to see if there is flow through the radiators. that will also show if the water pump is workling

(think this will only work if the thermostat is off .. or you use boiling coolant which i think would be a bad thing to try lol)

 

[farmerj]

Thanks, I will try both of those things.

I didn't want to stop riding, so I removed the thermostat from the housing and flipped the housing over, thinking the hoses might hold with "free flow" and a different orientation. Now the top hose popped off.

At one point I did put a rag over the radiator cap and remove it while "hot" (or so I thought) to see if I was overheating. No boil over, no pressure, no steam - it is a somewhat of a mystery to me. There must be pressure if the hose is coming off - but then it would be seen at the cap. Maybe I didn't run it/heat it up as long as I thought.

I'm running Engine Ice btw, maybe it doesn't boil over like ordinary anti-freeze.

Thanks for the help, I'll let you know if it looks like o-ring or air lock!