coolant boiling

[madcow]

i am hoping someone can tell me if my problem is in fact a problem or not (oh and how to fix it).

i will start by saying it has been 110/115 degrees the last couple of weeks were, so it may be a contributor.
when i go to start the nomad the coolant bottle is always empty, when i warm up the bike the coolant bottle will fill up from the engine (enough to overflow) and air from the inlet pipe boils to the top.
when the bike is switched off the coolant level drops down until its empty again.

the fan is working well and the temp light is not coming on, also the bike is otherwise running fine. it has me beat what is going on here so any help would be really appreciated, thanks, mc. ???

[misunderstood]

could be the radiator isn't allowing the water to flow properly to cool. Just a thought as my mechanic had to clean out mine with acid to clear it. Beyond that I don't know. Sorry

[goldstar225]

Have you checked or replaced the thermostat? It may be stuck in the closed position, keeping the water from circulating thus overheating.
Another thing, even though the coolant is overflowing the recovery tank, I would still try to keep the tank filled to specification.

[blowndodge]

Something IS wrong! When your engine is cold you SHOULD have radiator fluid in the overflow resevoir between the high and low mark. I need more information like year of Nomad and any mods you have done or have been done by someone else on the bike.

When hot does your bike Ping or have a detonation issue "pre-ignition"? Your coolant should never boil because of its chemical composition. A 50/50 mix of distilled water to coolant should forstall "boiling" far beyond the temp of your auxillary fan which you say works.

Without knowing your bike the first thing I'd do is take off the tank and completely drain the colling system. Inspect the cap to see that it's sealing properly. Refill your system with the proper coolant 50/50 mix, encluding bleeding the air out and making sure your overflow is properly filled with the same mixture.

Again I don't know enough about your Nomad's history of mods to have additional suggestions.

[cactusjack]

You've got a problem, although I am not sure what it is. I ride in temperatures between 110F and 120F in Phoenix and have never overflowed my coolant bottle.

How old is the coolant? If it hasn't been changed in the past year, I'd drain the cooling system and replace the coolant. Also, check for leaks at all cooling system hose connections. A leak will reduce the efficiency of the cooling system by not allowing pressure to build. It may also be a bad radiator cap. If the spring has gotten weak, it won't build the pressure in the system and will release coolant to the overflow jug.

Just a couple of thoughts.

[dogdoc]

your reservoir tank should never be empty! It should be half full at least when cold and it regulates itself from there. sounds like you do have a problem somewhere in the coolant system.

[misunderstood]

I would make sure the radiator is not clogged and replace the thermostat as was suggested.

[nomad]

well, on a car when you see bubbles and whatnot it is one indication that the head gasket
may be bad...not sure if that applies to a bike or not. good suggestion on the thermostat though.

[madcow]

thanks for the help guys, its a 98 nomad and is all standard mechanically. i tried looking for the radiator cap with no result so i assume that the cap is under the fuel tank?. i will order a thermostat and cap and also flush the cooling system on the weekend and see where it goes from there. thanks for the ideas and i will let you know how i go.

[timebandit]

Originally Posted by Nomad

well, on a car when you see bubbles and whatnot it is one indication that the head gasket
may be bad...not sure if that applies to a bike or not. good suggestion on the thermostat though.

That;s what I'm thinking also. I'd go to a radiator shop and have them pressure test the system with a hand pump. You would see if the cooling system as a leak due to the head gasket or pinpoint other leaky points!

good luck

[ringadingh]

I would also first suspect the thermostat, also check the rad cap for pressure and clean any crud that builds up under the rubber cap seal and neck were it seats. Does your fan kick in? maybe the sensor is bad not allowing it to come on when it heats up.

[refugio]

Let us know how it does after changing the thermo and cap.....Good Luck

[madcow]

i ordered the new cap and thermostat today and will keep you posted how it goes..

[macmac]

Replace the T stat, flush the engine and the rad before or as you do. Run plain water next. (Yeah I know you will have to access the cap again, it life)

Remove the rad screen so you can touch the rad.. Start the engine and feel the rad at the top, don't leave! Keep feeling the rad and as it heats up move down feel it left to right and move down as it heats.

If you discover cold spots this rad is clogged.

If the rad gets evenly hot, then you need to go to the dealer and get the gasses checked in the cooling system. The dealer I hope has a tool with a fluid that changes colors if exhaust is present, or you can buy the tool your self.

And run this system full at all times. This engine is partly air oil cooled and the rest is 2.5 qts of coolant.

It fills the over flow container because it is over heating.

[blowndodge]

Macmac awakes from the fridged east to bestow his knowledge.........