[hdhype]

What I have: S13 chasis w/ s13 SR20DET, Aluminum Radiator, Dual Electric Fans, Colder Thermostat (I don't remember open temp); New Head gasket, new water pump. 40% coolant & 60% Water (Rad, fans, thermostat, head gasket, and pump installed < 50 miles ago, also head was hot tanked and decked)

Problem: After about 15-20 minutes of driving (Seems to happen when I go at a constant speed, and not stop&go), engine heat starts to rise while both e fans are on. I can usually offset this for another 10-15 minutes if I turn on the heat in the cabin full blast. (I keep my rpm between 2000-3000)

What I have done: I've tried bleeding the coolant, raising the front end and massaging the top hose, along with turning the bleeder screw. I've ran the engine with the rad cap off, and I don't see any bubbles, but the coolant level rises a little bit, I'm guessing from the pressure from the water pump. I don't notice any white smoke coming from the exhast.

Edit: I've also searched for another thread with possibly the same symptoms and came accross one with some guy who started posting a bunch of pictures of cars he worked on, and that SR20's arn't ment to cruise 3500+ RPM or they over heat... That thread turned to shit really quick.

What was mentioned in this thread:
1. I have dual shrouded e fans. One is toggled to turn on with temp, the other is connected to a switch that I control. They both work. they both are on the engine side of the Rad. They both pull air through the rad, and towards the engine. This was tested by using a sheet of paper to show direction of air travel.
2. I made a make-shift air scoop underneath my bumper to direct air flow.
3. My resevoir went from max to min in 2 weeks, either I have a leak (Doesn't look like it) or I didn't correctly bleed my coolant all the way.
4. I did what aga said to do, and hold on to my rad intake hose, and rev the engine to feel for pressure to check for a hole in my gasket. (Later determined to not be an effective way to test that)
5. With the air scoop, it appears that I am able to keep from busting the max temp, as long as I have the cabin heater fan on full blast, and both my e fans are turned on, this however is very inconvenient, and was tested by driving conservitively.
6. I could switch back to the OEM clutch fan/shroud, but I don't want to spend the time/resources to do that.
7. My rad temp at the rad inlet hose was 198 degrees F.
8. My resevoir doesn't smoke.
9. My Rad Cap is in working condition.
10. New Nismo colder t-stat

Update: 6/21/2019 - I have since gotten rid of the car and moved on years ago, but let me tell you what happened because this is the second result to pop up when searching "sr20det overheating."
I purchased a coolant leak test kit and it showed that my coolant was getting exhaust gasses. I come to figure out that a couple of the head bolts where stripped when installing the head. it wasn't enough of a blown head gasket to cause white exhaust smoke. I ended up pulling the whole motor apart, and re-tapping to 12mm head bolts instead of the stock 11mm. I don't recommend this for DIYers, instead I'd recommend buying a new bare block and starting from there. What looks like was happening, is that while the head was on tight enough to stay cool under idle, boost would cause the gases to escape and enter the coolant system. After I corrected the head-bolt-stripped issue, I didn't have overheating issues anymore.

The best advice I can give anyone trying to chase down a problem is to not ignore gut feelings, and don't keep yourself from finding the problem to the issue out of denial. Also, one of the most liberating things I have ever done was getting rid of the burden of a project car. (I have since picked up another one, albeit it is daily-drivable, and I pay others to do the hard work for me now)