Coolant leak question


.060 Over
Sep 4, 2019
Houston, Texas
2012 Triumph Rocket III Roadster
Hello Rocketeers,
Still trying to figure out this coolant thing on the Roadster. Topped off radiator a few days ago and
it needed about a cup full of coolant. Overflow was empty. With the radiator filled to the top, I then
brought the overflow to minimum. Now radiator is full and overflow is at minimum. I ride to work and
there and back can smell coolant. All hoses are tight and not leaking. There's a few drops of coolant
that has run down the engine. Over flow is empty now, but radiator is still full. Had no leaking coolant
until I filled radiator and brought overflow to minimum. It seems that I never have coolant in the overflow.
What is missing? Radiator cap is new. Thanks.

coolant leak.jpg
Last edited by a moderator:


Top Fuel
Nov 2, 2013
Timmins, Ontario
2012 Rocket Roadster
If you can see some coolant running down the engine, where is it coming from? Right or left side. Check the hose from the rad to the overflow tank for cracks. Does the overflow tank have a small hole in it? Also, the rad hose clamps might look tight but overtime the hoses can leak where they slip onto the block, water pump fittings and rad requiring a snug up. Also, you stated that the rad cap was replaced. Was it tightened all the way? Just guessing here.

John Miller

Jan 3, 2018
Brisbane, Queensland Au
2011 Rocket 3 roadster
If you have a new cap fitted then I would be looking at the hose and fitting connecting the bottle to the radiator and looking to see if the cap seat is distorted or damaged or the bottle itself might be compromised. IT appears to me that your problem is with the overflow circuit.
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