I drive a 89 Turbo II and I'm searching for a new radiator, as mine doesn't seem to be able to cool as well as I would like. It is heating up too much after a spirited 15 minute drive. This could be due to issues with the stock coolign of course, but seeing as how I will be autocrossing and attending track days, I would like the peace of mind of an upgraded radiator.

Which are considered to be the best? I have seen the Koyo single and double pass radiators for around the 360 mark. Is it worth it to buy the double over the single pass?

Also, what about other companies, like Fluidyne? I'm looking for as much cooling as possible within a reasonable budget.

 

i have a standard koyo aluminum radiator on my 89 and i have never seen it heat up with it.....

 

for that price range...the koyo and fluidyne are your best bet for a bolt in rad.
-a

 

The best cooling capacity will be found in any form of double (or triple) pass radiators. The only downside to them is you need to extend the upper (or lower depending on who makes it) rad hose to extend to the opposite side of the rad.

Koyo's are very popular and well made, also they are in the mid-range of pricing when it comes to upgraded rads.

If you are experienceing coolign issues with your stock components, I would first ensure that everything is in working order before dropping bread on a performance rad though. Because its been my experience as well as many others on the board and out in the world that the stock cooling system when functioning properly, shouldn't give you any cooling issues aside from some hugely extreme case like a 110+ degree day and flogging the **** out of the car with the A/C on up hill at 30mph.

Once you verify your t-stat and clutch fan are working properly, your shroud and belly pan are in place and that your rad's core is clear (although if it weren't you may as well get another rad) then you can move onto your purchase.

 

Also make sure that you have the underbody tray. If not you won't have proper airflow through the radiator.

And when you replace the thermostat, be sure to only use the OEM Mazda unit.

 

I do have the underbody tray. I do not, however, have any fender liner. Could this cause a problem?

My money is really on my stock components not functioning correctly. However, I just felt that this was an opportunity to upgrade anyway, especially since the car will be dedicated to autocross and open track.

 

tried the prestone diy backflush kit? you might be suprised what comes out :/ i was

 

if it gets hot on a 15min drive you gotta have a leak...not necessarily a bad leak but remember your cooling system is pressurized so any tiny leak will hurt your system bad. i had a tiny crack in my t stat housing, pinhole size and it caused my car to heat like yours after about 15-20 minutes.

 

well, yes, it does heat up after 15 minutes. However, for normal driving, the car will go for 3+ hours without any problems. The thing is, this was 15 minutes of pretty hard boosting while climbing a hill. :p

 

You cant beat the pice on the Koyo and I would say it's comparable to the Fluidyne. Not all the mounting holes on my friends Fluidyne radiator matched up to the stock mounting locations on his S4 so he had to look into having a bracket made for the radiator... maybe he ordered the wrong one, not sure what the story was, but its something you might want to look into before installation.