HELP ! This is a weird one.........To start this is what i have Stock rad., Flexalite 210 electric fan,Aux tranny cooler,180 thermostat,underdrive pulleys,cobra R water pump..I'm fine around town but on like a 45-1hour trip on the high way i'm overheating...I'm getting very hot and alot of pressure under the cap...The temp would fluctuate from very hot to norm temp then finnaly stay high...I turn on my heater full blast and the temp goes down but stays a little above norm and doesn't move ..but it's driveable to get home..I did a little search here and i see maybe a new rad ..but i flush my system every year? Also i saw maybe an air bubble ..how do you get rid of that? I know it's not the sender acting wierd because of the high pressure?I guess my 210 fan is a little undersized but it's been working for 2 years? I'm thinking t-stat is not opening but it's a hypertech and i think they are supposed to fail open? ANY IDEAS... HELP!!!!!!!

 

HI!... Unless your running under drive pulleys with that COBRA "R" pump, you are creating a problem with coolant flow. See the "R" pump flows more fluid than your stock W/P does. By running the "R" pump with under drive pulleys you are spinning it at about the same RPM as the stock pump with stock pulleys, but because the "R" pump is more effecient at pumping the water you will actually gain a bit of H.P. Running the "R" pump with stock pulleys is actually costing you power. It would also mess with your cooling system. You should also upgrade to two 16" DERALE electric fans. The 210 is junk IMO.

 

You have your fans as pullers right? Not pushers?
Jes

 

I had a similar issue arise when I went from the stock 2.73 - 3.73 gears in my old GT with U/D pullies. A better radiator fixed it.

If you haven't changed anything since the last "hot time period", what was the ratio of anti freeze to water ? You should run no MORE than 50% anti freeze - I run 30 - 40 % tops...

Best band aids I can suggest - 70% water + 30% anti freeze. Add a bottle of Red line Water wetter

If that doesn't make any noticeable difference, try going back to the stock water pump pulley. I don't think the Cobra R water pump is THAT much more efficient to be equal at under drive with the stock configuration.

I'm pretty sure that you're not going to be able to FIX this with any of the above suggestions, or a better fan. At highway speeds, your fan shouldn't even be an issue, air flow should cool the 'coolant mix'. I think you're looking at either the stock water pump pulley - or, a more manly radiator...

HTH

 

Do you have gas bubbles in the coolant? That is a sign of exhaust gas entering the
cooling system from a leaking head gasket or cracked head. Even with no fans the flow of air over the rad should cool it enough to remove any excess heat. Are the rad or condenser fins clogged? Is your 180° T stat deffective?

Check for clogs and change the T stat. If it still overheats look for bubbles in the radiator coolant recovery reservoir.

Regards

Jean Marc Chartier