UrS0NvS

guys, stop worrying about the size of the radiator. the owner of this site has a half core in his tib and is pushing far more boost than radu is.

ZKend

^^^agreed my boy is building a 700hp AWD 1g talon and is runnign a single halfcore from a civic... stock fan and everything

javageek

Another thing you can do is put in some of this. http://www.redlineoil.com/products_coolant.asp

radu_rd2

^ Yeah I'm already using Water Wetter

hamhead

I'm going to lean towards the water pump possibly being bad, or at least on the way out.

Its been 90 degrees here and I had a radiator fan fuse blow - the car idled for 10 minutes and it never went into the red, only slightly above normal on the gauge. Once the car began moving, the temperatures dropped down in the normal range. If all things are operating properly, you really shouldn't be overheating at highway speeds.

I'm running a cast log-style manifold as well, running about 1 bar on the turbo, sometimes more.

radu_rd2

I wonder how much a vented hood helps with airflow, esp. at higher speeds

Stocker

+1 for a suspect water pump, although I regret to say it due to the work involved in a replacement. Go ahead and see if a stock pulley does the trick. . . spinning the pump slower sure won't HELP with overheating anyway. After the pump, contact a major fan manufacturer and see about getting the highest-flowing model that you have room to fit in the space available. You want more CFM; just bigger is not necessarily better. Oh and if the shroud on the 12" is a restriction at high speed, adding another fan in the way that can't move as much air as the 12" is just another restriction. If the overheating really worries you, until you get it fixed right you might go ahead and wire the fan relay to kick on whenever the engine is running, to give it a little more time before it starts to overheat.

Also, you said the thermostat was good/new, but here's an anecdote for you: My sister's Diamante overheated ONLY at highway speed. Thermostat was only opening partially, restricting flow.

radu_rd2

One thing though - if when it overheats I turn on the HVAC on full heat, the temperature will quickly go down.. this should mean that the coolant flows fairly well no?

dddude55

I don't know the reason why but turning on the heat always helps. If your car starts to overheat you should turn on the heat and put it on your feet. Not sure why but that's what I have always been told.

2uniq

<div class='quotetop'>QUOTE (radu_rd2 @ Jun 14 2009, 12:52 AM) <{POST_SNAPBACK}></div><div class='quotemain'>I wonder how much a vented hood helps with airflow, esp. at higher speeds</div>

This is something i have always wondered about as well...You hear differentstories from different people when it comes to hood scoops.I have had my WRX hood scoop installed for 6 years now and is functional. Before i installed my Koyo rad my car,i would overheat everytime at temps of 230-250 on a hot summer day.this happened weather i was driving or in traffic...
I came to a conclusion that its probably worse to have a hood scoop (UNLESS its the reverse style like the Zefiero hood) because the humid air rushing in would actually bring up ambient temperature ,But when i installed my Koyo rad the overheating issue was gone fing02.gif