Hi
I have a 1986 Honda 1500, which has been modified slightly. The cooling system is working fine after a few hick-ups but we see that the expansion bottle close to the radiator isn’t working, as it should. If there is a water shortage in the system it is suppose to suck coolant from the bottle to the radiator, and if there is too much coolant it’s suppose to return to the expansion tank. The return bit is working fine, but the part were coolant is supposed to be suck up isn’t working. What can be wrong, could it be a leak in the system, so that the pressure isn’t enough, or can one bypass the expansion tank completely, and close it of, leaving a closed cooling system.

Any advice would be helpful

Thanks

 

When the cooling system cools down the pressure inside the cooling system contracts. When this happen the radiator cap allows the coolant to follow back to radiator from the coolant resivoir. And when pressure raises to towards caps thershold, the cap opens up the allow coolant flow into the coolant resivoir.

However, does your coolant hoses collapse in the morning when it's cold( like upper and lower radiator hose)? If not then your radiator is okay and your cooling system also.

 

Thanks for the reply

No the coolant hoses doesn't collaps in the moring, but coolant keeps been flowed to the expansion bottle, but doesnt return to the radiator, so i need to keep filling / topping it up.

Any other help

 

Have the radiator cap tested by local shop just to sure that is good.

Also, I forgot to mention that to make sure that you don't have any coolant leak.