Benzfan2018

I checked my coolant level in my reservoir for my CLK350 and i noticed that the cap could be tightened more but how can you know when the cap is tightened enough? I don't want to over tighten the cap but I don't want it to be too loose either. Any comments are appreciated and have a good evening.

optimusprime m1

It will lock in place dont leave it loose the system wont work properly is its loose .You wont be able to over do it by hand only. But dont use a tool to lock it up. . When the coolant gets to temp it transfers coolant in to the engine it then circulates the engine to keep it cool and return via the pipe from the top of the radiator to the catch tank .If the cap is not in place the cooling cycle wont happen ..

Benzfan2018

Thanks for the comment. The reason why I brought this question to the forum is that the coolant reservoir and the cap are both plastic and i don't want to put too much force on the tank filler spout. I just tightened the cap until there was resistance then tightened two more rotations and called it good. What I'm trying to say is I don't want to torque the cap so hard and I break the tank. One more comment I have is if the cap locks on the tank is there a click or do I just tighten all the way to the end of the thread? Any suggestions would be helpful.

optimusprime m1

As long as you have fitted it hand tight that will be fine .Dont forget that you might need to open it at some time .And no it wont click .The cap will have a rubber type seal that closes on to the neck of the tank it should be ok.