Thermostat issue?

[Trek55]

New forum member here. Dealing with a coolant issue on a 1999 Nomad with 52K miles on it. Bought the bike about 2 years ago and thoroughly enjoy it, have put 7K miles on it since purchase with no issues. Late last fall the bike had a trail of leaking coolant after a short ride(I think from the overflow tube underneath the bike). I have taken it to the dealer who indicated there is no issue...however, bike did this two more times. So, I have drained and flushed the coolant - it now has distilled water only. Hoses look good and firmly connected. Plan to put engine ice in it when confident with any repairs. When it warms up enough for the fan to kick on, the reservoir is literally boiling with water. 1. is this "normal" 2. Is it possible the thermostat is not functioning properly? Should I test it to confirm...and if so is it housed on the right side of the bike? Any insight is appreciated. Thanks, Tom

[tomm]

If all the connections are good, my first guess would be the radiator cap. Right side of bike. If like the 1600, you have to remove the gas tank to get to it.

[redjay]

The thermostat can be seen in this diagram. In a 99 Nomad I would be changing the thermostat as the first part of the diagnosis. It has probably never been changed before anyway.

https://www.ronayers.com/oemparts/a/...8e67e/radiator

[DragonLady58]

Well, Welcome Aboard! Sorry to hear about your problem, no, Nomads are one of the most dependable bikes out there.
OhHellNo it ain't supposed to boil in the reservoir! Your either sucking air into the cooling system, its leaking not holding pressure, if it heats up faster than normal, its the waterpump or a leaking head gasket....
Since your having problems, even though the hoses look good, need to replace them if they have never been replaced before. You'll probably find a soft spot somewhere. And replace the thermostat, along with a new rad. cap. Thermo and cap are under the tank/speedo....
Since you said the fan IS coming on, the fan and switch are working. Look at your radiator. Shine a light thru from the front. If you see little light, spray some simply green onto the front of radiator, let it sit, do it again, do this 3 times.
Now, get your garden hose, with your favorite spray nozzle, turn it on full bore,start washing it from the engine side, go slow, and wash it out good. Then do it from the front. Do this several times....if you can't see thru it, air can't flow thru.
If that was really stopped up, that mighta been your problem. If not, keep looking. Make sure your resv. doesn't have a crack in, also check the thermo housing under the tank. They have been known to leak.
If no joy there....its waterpump time....
Clean your rad. good and recheck all your hoses for softspots, also your rad. cap gasket, thermo, and the reservoir, and get back with us....

[mick56]

I have a 99,and had the same problem.I fitted a new thermostat and rad cap,still had the problem.I put it down to a head gasket,and used some Kseal.That cured it.
https://www.kseal.com/uk/?gclid=Cj0K...QaAkSXEALw_wcB

[recumbentbob]

A new radiator cap fixed my 08 nomad when it did that.

[Trek55]

Thanks to all for your replies and advice. Since I really don't know the maintenance history on the bike I'm opting for changing most all the cooling related hoses, radiator cap and thermostat. Will order parts soon and report back.

[Trek55]

Thanks to all who responded. The culprit was indeed a bad thermostat. Due to the age/miles on the bike I opted to replace ALL cooling related hoses, thermostat and radiator cap. I'm not a mechanic, but don't mind getting dirty, so I tackled the job myself. Six hours of meticulous detail and contortions to get to all the clamps, etc...and of course some choice words *^%!@ along the way.

The bike is running like a top now and several long trips during the summer heat confirms a solid fix. Thanks again to all, and happy riding!

[Chuck A.]

Originally Posted by tomm

,,,,,,,,,,,,,,,,,,,,,my first guess would be the radiator cap…………………………….

That was the problem with my 1500 2 years ago.

[Tortuga]

Are there aftermarket or car parts that will substitute for overpriced dealer parts?

[hammer]

Try this link,
http://http://tearitupfixitrepeat.bl...iator-cap.html
I am going to pick a Stant version of a cap for a '96 Honda Accord. Rated at 16psi and will do the mod shown if needed. Sitting at the border a day ago waiting in hot weather it steamed off and the fan did not come on. Assuming the cap is all I need short term, I am going to intercept the fan wires and install a manual override switch so I can turn the fan on at times I know I will be standing in line. The cap is 1/4 the cost of the Kawi cap and the bike sure won't know the difference.

[mick56]

Any motorcycle 1.1 bar rad cap will fit.Mine is for a Honda CR125/250/500,and fits dozens of different bikes.Cost about $10 on ebay.It is easier to fit if you cut one of the ears off it though.

[hammer]

Yup Mick that's right on target. 1.1 bar = 15.9+ psi. As far as I know, the cap does not need to be bike specific or even a motorcycle cap to do the job. Except for fitment specs and temp spec, I wonder if that applies to thermostats too.

[mick56]

Originally Posted by hammer

Yup Mick that's right on target. 1.1 bar = 15.9+ psi. As far as I know, the cap does not need to be bike specific or even a motorcycle cap to do the job. Except for fitment specs and temp spec, I wonder if that applies to thermostats too.

Kawaski dont make thermostats.In fact they dont make much at all.Like every other company,they buy in the cheapest shit they can get hold of,and sell it to us at extortionate prices.There are are some places you can cross reference parts.I found Ron Ayres to be usefull.Be good if others chimed in here.
https://www.ronayers.com/oemparts/c/...torcycle/parts

[hammer]

Actually, thanks for reference to the Honda machines. So far though, the Honda car cross reference should work. I will take the cost hit if it does not and post results.