Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Are all radiators the same?

  1. Mar 16, 2007 #1
    Are all radiators the same? I've got a five-month-old Integra and already I have done a radiator replacement because the one stockfitted on the engine bay can't allow the Integra to breach the 70 mph mark. I looked around at an auto radiator shop called http://www.overnightradiator.com/ The replacements available for my Integra looked all the same to me. I looked them up at the specs sheet but I can't get the whole picture, they might be all empty talks, you know what I mean? I figured to look for info first before I get a replacement. I'm a little green on this subject, so may I ask you guys what I should get?
    Last edited by a moderator: Apr 22, 2017
  2. jcsd
  3. Mar 16, 2007 #2


    User Avatar
    Science Advisor

    I don't understand what the radiator has to do with the vehicle not being able to attain a certain speed. Unless the car is overheating, it doesn't.

    Radiators can have the same physical size, but differ in performance. The one thing that is the most influential to its performance is the surface area that is exposed to the fluid streams inside. The area is created by folds, bends, fins and anything else that can be done to make the exposed area as large as possible. Usually, for a car, the radiator is sized for the power output of that paricular engine. There are other aspects that can have an effect, but that is the biggie.
  4. Mar 16, 2007 #3


    User Avatar

    Staff: Mentor

    Also, radiator and engine efficiency both increase with speed until you get to your top gear and radiator efficiency continues to increase from there. A car should not overheat because of going too fast, most die due to driving in 1st gear too much (ie, in traffic) or while not moving.
  5. Mar 17, 2007 #4


    User Avatar
    Gold Member

    Unless you've done engine modifications that would increase the heat output, the stock unit should be more than adequate for any normal climate. As a possible complication, check to make sure that there are no obstructions to the air or fluid flow in the area. An aftermarket fancy grill, for instance, might not let enough air through.
    The first thing that I would investigate, however, is to make sure that you have the proper thermostat and that it's in good working order.
  6. Mar 17, 2007 #5


    User Avatar
    Science Advisor
    Gold Member

    Why can a 5 month old Integra not go above 70mph?

    You shouldn't be needing to replace any parts like radiators after 5 months. And, as others have said, I don't see how the radiator is limiting the speed.

    More info please.
  7. Jul 10, 2007 #6
    You should check the thermostatic valve, which is typically placed somewhere in the coolant-loop (either near the radiator or near the engine block - See your workshop manual for the specific location). These are typically mechanical units, and thus may vary in calibration. Thus, if you have a unit with a slightly higher than normal opening temperature and you are in a hot climate, your engine may tend to overheat. These valves aren't too expensive, so the easy choice might be to simply to replace it, and see if it helps...

    As others say: There is NO way a badly functioning radiator will limit your top speed. It may cause your engine to overheat if you run it at high rpm's for extended periods, but more likely you would see the engine overheating while standing still and idling for long periods (as this is the situation where the least amount of air pass through the radiator, even despite the radiator fan operating).

    If your car simply won't go beyond a fixed speed, it is much more likely due to a restriction in the injection (or ignition) electronics. In that case you could possibly get a replacement chip for the engine, without this artificial limitation. Most car factories provide such "tuning chips", and otherwise there are a number of companies specializing in making them.
  8. Oct 19, 2010 #7

    Ranger Mike

    User Avatar
    Science Advisor
    Gold Member

    All the above is good input but i have a few questions
    when did this 70 mph cap occur?
    has it always been this way or did it just happen?
    what were the driving conditions prior to this mph cap?

    with todays car designs for max MPG and highly aero dependant the front of the car is really restricted regarding air input. since the intake air intake and grille to the radiator are both up front, i suspect the intake air filter and radiator may have got plugged to the point of now working to max efficent. did you check the air filter?
    were you driving on a real dusty dirt road just before the car started acting up?
    did you blow out the radiator core with an air nozzle before you took out the radiator?

    we do not assume anything when we trouble shoot so you got to look at everything
  9. Oct 19, 2010 #8


    User Avatar

    Staff: Mentor

    Old thread, brought back by spam. Locked.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook