Coolant Check

[johnparjr]

Was always wanting to know and I did a search and came up with nada should you check your level on the overflow bottle when the bike is cold or warm it seems when Im riding the over flow is where it should be but when the bike is cold it's low. So BARF mechanics whats the correct way

 

[ST Guy]

It's done with the bike cold. That's when the greatest amount of coolant is in the main cooling system and not in the resevoir. Since you need a certain minimum in the resevoir to make sure that air never gets sucked into the cooling system, it makes most sense to check it cold when the least amount is in the resevoir.

Hope that helps.

 

[ST Guy]

Oh, I should add that if you only check when the bike is hot and see that there is still some coolant in the resevoir, that might not be enough to prevent air from being sucked into the main part of the cooling system. As your bike cools and the coolant contracts as a result, a vacuum is created in the main cooling system (provided it's in good shape with no leaks) and coolant that was expelled into the resevoir is sucked back into the main part of the system. If there's not enough coolant in the resevoir, then the main cooling system then starts sucking air into it and you end up with cooling problems. The only way to know if you have enough coolant in the resevoir is to check it cold.

 

[johnparjr]

Sometimes when cold its at the low mark and other times when cold its below it so I added a little to put it in the middle of low and high

 

[teg916]

Sometimes when cold its at the low mark and other times when cold its below it so I added a little to put it in the middle of low and high

I would fill it until it is at least at the low mark when the bike is cold. You don't have to worry too much about overfilling it because any excess will just go out your vent hose.

 

[PGATour]

1) Is there supposed to be any coolant (water wetter) in the overflow reservoir when bike is cold? both my bikes have nothing in the overflow reservoir (Duc 998 and GSXR600)... I thought this was normal. Plus, I just had the overflow reservoir replaced in the Duc by Nichols, so I thought if anything was wrong or if it was supposed to be filled they would have told me about it.

2) If I'm topping off the coolant, do I fill it by adding into the overflow reservoir? Or the actual metal cap on the radiator itself?

Thanks in advance for clarification!

 

[teg916]

1) Is there supposed to be any coolant (water wetter) in the overflow reservoir when bike is cold? both my bikes have nothing in the overflow reservoir (Duc 998 and GSXR600)... I thought this was normal. Plus, I just had the overflow reservoir replaced in the Duc by Nichols, so I thought if anything was wrong or if it was supposed to be filled they would have told me about it.

2) If I'm topping off the coolant, do I fill it by adding into the overflow reservoir? Or the actual metal cap on the radiator itself?

Thanks in advance for clarification!

Yes there should be coolant in the overflow reservoir. Your overflow reservoir is there to keep your radiator topped off at all times. When the radiator gets hot fluid will go to the overflow reservoir. When it gets cold it will suck a little out.

Normally you would be ok just topping off the overflow reservoir. If it is completely empty check the radiator too.

 

[ST Guy]

Sometimes when cold its at the low mark and other times when cold its below it so I added a little to put it in the middle of low and high

 

[ST Guy]

Yes there should be coolant in the overflow reservoir. Your overflow reservoir is there to keep your radiator topped off at all times. When the radiator gets hot fluid will go to the overflow reservoir. When it gets cold it will suck a little out.

Normally you would be ok just topping off the overflow reservoir. If it is completely empty check the radiator too.

What he said. I would add that if the main part of the cooling system sucks air, then that means there is now something in the system that can be compressed (the air) and that will prevent the coolant from pressurizing. Coolant needs to be pressurized to avoid boiling over. Too much air in the system and you'll boil the coolant and overheat.