Hello everyone, here goes for my first post.

I'm having some real trouble with my XT660R radiator whenever it's at idle or working real hard off road.

It seems like the fan isn't coming on when it should and the coolant is getting real hot and spitting out of the overflow pipe after 5-10 minutes idling. The fan does work but there doesn't seem to be consistency with when it comes on or not.

Also, during my investigations I ran the engine without the radiator cap off just to see what was happening in there and the fluid if pouring in to it from the pipe coming from the thermostat as soon as the engine starts...... I thought that this should only happen once the coolant reaches temp.

Any suggestions?

In addition to this post, is it possible that I have connected up the radiator hoses incorrectly. I would have thought that this would somehow 'break' the system by making it work in reverse but maybe not. I am starting to think that the two hoses attached under the radiator cap are the wrong way round..... I currently have the thicker one (from the manifold?) attached at the top and the smaller one which leads to the overflow bottle attached below this.

I would feel pretty stupid if this was the case but also glad to find the fault.

Have you tried draining and refilling the system?..wondering if you have an airlock or even a failing water pump?..or thermostat?..Have you checked the electrical connections?.

Have you taken the hoses off?..

I recently changed my coolant,mine's an R too,and filled it with tap water and let if heat up/open the system a few times then used the correct coolant..

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