Coolant level - to the bottom of filler neck?

[Dmitry]

Hi, I got Rover P4 90 2 months ago. Received the manual that says that water level should be at the bottom of the filler neck. But when coolant expands in hot engine, it leaks through the overfill line onto the ground. When it cools down the level becomes below the filler neck. I replaced the filler cap, but still getting the same behaviour. So how should I maintain the level in the radiator? Should I just leave it below the neck and keep an eye on it? How do you maintain it? Thank you.

 

[bobbymac]

Hi, I got Rover P4 90 2 months ago. Received the manual that says that water level should be at the bottom of the filler neck. But when coolant expands in hot engine, it leaks through the overfill line onto the ground. When it cools down the level becomes below the filler neck. I replaced the filler cap, but still getting the same behaviour. So how should I maintain the level in the radiator? Should I just leave it below the neck and keep an eye on it? How do you maintain it? Thank you.

What you could do is fit an expansion tank into which the overflow pipe will drain. As long as the end is always underwater, the expansion will add to the expansion tank and on cooling, the coolant will be drawn back into the radiator.

 

[Dmitry]

What you could do is fit an expansion tank into which the overflow pipe will drain. As long as the end is always underwater, the expansion will add to the expansion tank and on cooling, the coolant will be drawn back into the radiator.

Thanks Bobby. I think you are right, I am considering that. Just wanted to understand what the normal behaviour is, and how I should deal with it properly without modifications first.

 

[harveyp6]

Coolant wont compress so if you totally fill the system it will always push some out under the cap as it expands. You always need an air gap. Don't fill it to the very top and it will be fine.

 

[Dmitry]

Coolant wont compress so if you totally fill the system it will always push some out under the cap as it expands. You always need an air gap. Don't fill it to the very top and it will be fine.

Thanks harveyp6. That makes sense. What they probably meant in the manual is Fill it up to the top, and the system will get rid of the excess automatically - refilling with rain water is free and harmless for environment I'll probably install the expansion tank with the level sensor or put the level sensor into the radiator.