colerongo Posted November 20, 2011 Share Posted November 20, 2011 So I just installed a Four Seasons Racing double pass aluminum radiator into my ka24de 280z. Since the install I have not been able to get my cooling system to function properly. Beforehand I would run at a constant 180 degrees with the oem nissan thermostat. Now I am running between 180 and 200 degrees measured with an autometer gauge with sender located in the water outlet where the stock bleed screw was. I do not like having an unstable temperature, I just want it to sit steady at one temperature. I have tried every method I've been able to find from the 240sx crowd to bleed the air out of the system so I don't think that is my issue. Still my lower radiator hose is cold. I went for a long drive this morning (Air temp was around 45 degrees) and my lower radiator hose was COLD. I don't mean cool, I mean cold. Even when my engine temps started to reach 200 degrees at the upper hose. So my thermostat obviously isn't opening. I am wondering if maybe my new radiator is too efficient and since the thermostat is on the lower hose it is not able to open with that cold cold water on the front side of it. So i'm trying to figure out what to do here. Should I drill out the air bleed hole a little on my thermostat to allow more water to pass through when the thermostat is closed? Should I try running it without the thermostat? Should I install an inline thermostat housing on the upper radiator hose and put the thermostat at the hot side of the engine? I haven't heard of anyone doing this, but seems pretty logical to me. I don't understand why anyone would want their thermostat on the lower radiator hose anyways. Let me know what you guys think here. I'm sick of trying to bleed this thing and still have it running hot. I don't like staring at my temp gauge all the time. Thanks Quote Link to comment Share on other sites More sharing options...
frankist Posted November 21, 2011 Share Posted November 21, 2011 are you using a aftermarket radiator for a 280z or 240sx radiator tilted? did this happen after the radiator install? do you have the heater on while trying to bleed out the system, the shutting the heater off once hot air is notice? Quote Link to comment Share on other sites More sharing options...
colerongo Posted November 21, 2011 Author Share Posted November 21, 2011 I currently have the heater bypassed so bleeding should be even easier. Yes it started acting this way since the new radiator. The radiator isn't for a 240sx or a 280z. It's a double pass chevy style radiator built for circle track cars. I'm wondering if the headgasket is leaking enough to let some exhaust gases into the cooling system and fill it with air bubbles. I just ordered some arp head studs and a new fel-pro gasket set. I wanted to do this anyways so I know I can trust it when I put a turbo on it. Quote Link to comment Share on other sites More sharing options...
frankist Posted November 23, 2011 Share Posted November 23, 2011 id try bleeding it on a hotter day, 45f outside is pretty cold. or using a piece of cardboard in front of the radiator just to get the thermostat to open and bleed out, try letting it warm up a bit more than 200 to see whether the thermostat will open or not. shouldnt be a headgasket if it never did it before. any pictures? =) Quote Link to comment Share on other sites More sharing options...
Alonso* Posted November 24, 2011 Share Posted November 24, 2011 Have you tried running a radiator breather tank? I've run one on both my turbo s13 and dd s13 with great results. Quote Link to comment Share on other sites More sharing options...
colerongo Posted November 28, 2011 Author Share Posted November 28, 2011 I took out the thermostat and it doesn't get up to temp even with the fan unplugged. So I'm going to buy a new thermostat from Nissan. Alonso, I haven't tried running a radiator breather tank. How does this work exactly? Do you mean an overflow/expansion tank? Quote Link to comment Share on other sites More sharing options...
ZeeNoEvil Posted November 30, 2011 Share Posted November 30, 2011 Sounds like air in the system by the way the temperature varies. Run the engine to operating temp, then clamp or pinch off the upper radiator hose. Run the engine at 2,000 rpm for about twenty seconds releasing the clamp on the hose, continue running at 2,000 for another ten seconds, shut off the engine and let sit for a hour. Check your fluid level. A more sophisticated way would be to drain, vacuum down the system then let the vacuum draw in the fluid. Quote Link to comment Share on other sites More sharing options...
colerongo Posted December 8, 2011 Author Share Posted December 8, 2011 So after installing a new thermostat and bleeding it on a steep hill my temperature is constant at 180 degrees! Also, just because I'm overly anal about how my car runs I rented a block tester from Auto Zone to see if any combustion gases were getting into my cooling system and it all checks out fine. Running at the proper temperature again, the KA sounds better than ever. My wife drove the car to work in Napa today so I got to hear it driving next to me and wow it sounds sweet. I can't wait to hear it with a turbo! Thanks guys for the recommendations on getting my cooling issues taken care of. Quote Link to comment Share on other sites More sharing options...
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