I recently replaced my water pump. Id made sure my coolant is clean, replaced the top and bottom radiator hoses. The thermostat is fine, the air dam is fine, why does my car heat up and why does pressure get released into the reservior rather than me pulling the safety cap on the radiator cap?

 

Bad radiator cap?

 

because your radiator cap has a pressure valve...say your cap has a 10 psi rating...might be 15..i don't know. when your coolant gets hot it expands, creating pressure. if it exceeds 10 psi or whatever your cap is rated at, the valve in your cap opens and directs coolant or your excess pressure to the reservoir.....however if your cap is bad, and the valve is stuck open, your system wont build pressure and it will keep distributing coolant to your reservoir. you need pressure because for every psi, you raise the boiling point 3 degrees. without pressure you boiling point will be low, which can cause overheating and air in your coolant from boiling. get your cap pressure tested...

 

also, if its 2 years old, replace it. it has done it's job.

 

I replaced the cap a few weeks ago, its then safety radiator caps, i guess its rated at 16 lbs...

 

haven't replaced my cap for 4 years.. its still doin its job

 

RebelGQ, does the bottle fill up & over flow? is your car over heating?


most manufacturers recommend replacing the rad cap at between 2~4 years.
at 2 years old the seals in the cap are no longer as pliable as they need to be & may not seal properly when removed & put back on. also the spring may be getting weak.
i have seen caps less than 3 years old turn loose & burn up the motor.
i know people who have used the same cap for years, 1 or 2 of them for over 10 years & never had a problem. a friend of mine even ran the same factory coolant for about 12 years, almost 285,000 miles with no problems, just added some water when needed, would you do that?
for what a cap costs, i replace mine with the belt & flush i do every 2 years.
for people who actually open the hood & check the fluid levels, belts & hoses, & for other problems like they are suppose to do, going longer is fine.
but, for the people who never open their hood & think having everything checked by a shop when they have their oil changed is good enough, they need all the help they can get, especially the ones who get their oil changed once a year.

 

with the new radiator cap, it kinda leaked, but i did remove excess coolant from the reservoir. i did replaced my water pump two weeks ago. I can always get another rad cap, this time i'll get just a 16 lb cap, without the safety lever