JDM b20b stock internals running only 5lbs... Has slightly larger injectors and skunk2 manifold and that's about it..has some aem pcm... Not sure its my buddies car. Anyway... The other day the fan shorted out and he bought a mishimoto fan and wired it in... Fan works great.. Only issue is now it's overheating. It idles and stays around 190... Once he starts driving rises to 200+. The bottom radiator hose doesn't get warm until after its been driven... Eben at 190 it feels like the tstat doesn't open... Here's the kicker, brand new tstat, water pump, and head gasket. Swapped the tstat out and didn't solve issue. Buddy hasn't dogged car in months so could the head gasket really be blown? We tried everythingm.. Could the water pump be out already?

 

Have you tried running it without the thermostat and see what happens with the temp?

 

air in system?

 

My guess is the new fan was wired incorrectly, very easy to mistaken. Check to see if the fan is pulling air INTO the engine bay, blowing air towards the engine, if it is sucking from the engine bay and blowing at the radiator, you will have these exact symptoms. Very easy to fix just flip the polarity on the fan wires

 

I would have to agree....

 

Fan is mounted correctly and spinning the correction direction with polarities correct. We tested with it front mounted pushing into radiator and stayed with back mounted to pull from the radiator INTO the Baum. No unruley gaps either... Only disparity is that fan hangs off center abput an inch to allow the turbo clearance. Could that small amount open radiatorcasue this by it be sitton too close to the turbo?

 

The fact that it is a cheap mishimoto fan is possibly your problem, the 12" only flows about 600cfm which is very low, and if you dont have a shroud your not cooling much of the radiator with that poor 600cfm, add ontop of that it sounds like the turbo is very close radiating heat and soaking the radiator isnt helping

But you say the lower hose never feels like it opens even past 200*, thats a huge problem right there, something is wrong with the thermostat installation or it is failed, check its installation/test thermostat in hot water on the stove or just straight pull it out. If the thermostat isnt openning, there no way to keep the car from overheating

 

So the fact about the fan, we ditched the mishimoto and went back to a 14" not sure brand and it isn't shrouded but not sure why all of a sudden.... The turbo as always sat right next to it and it was never an issue. As for the tstat, we have tried 2 brand new installed correctly and tested both in boiling water. They open fine. Going to attempt to run without it and see. Thanks for all the valuable input... Please keel the opinions coming (IMO I told him sell the turbo and buy a VTEC head and go na b20v but he's stubborn, Lol)

 

If the thermostats are opening fine, then the car surely isnt @ 200* with the lower hose being cold. How are you measuring the coolant temp? An aftermarket gauge on the upper line perhaps? The water coming out of the head on the upper hose is much hotter than what the sensor mounted on the thermostat housing or back of block sees, could be as much as 30* difference

 

Well after he drives it heats up and the bottom hose is hot but not as hot as the top hose. So any have the there is a clog in the main pipe behind the block? Also, yes the temp is coming from the inlet at The head. There is no switch plugged into the tstat housing since the fan is wired in directly. Also, the switch in the head that leads to the gauge in console is recntly burned out. He just had a full flush when he got the pump replaced. Could there be some gunk blocking it up?

 

200* coolant coming out of the head on the upper hose is perfectly normal, after that coolant goes through the radiator it is back down to 180ish where it would be read by the stock sensor in stock location.

225 or more on the upper hose and its time to start worrying

A $10 investment into some Water Wetter treatment would be money well spent to help your friend sleep at night

 

Well just did compression test and came out all good. Gonna do leak down test this week... Trying to get a compressor.... But as for the 200... It rises to almost 220 before he shuts it off....