[Roadsters] Overheating Question Part II

[Matthew Cox]

Helo everybody!  I have another question about my little overheating problem. First of all, thanks to everyone who sent replies to my last email about this. I really appreciate all of the ideas! 
   
  I am going to past my original email here so that everyone is up to speed:
   
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  Hey guys!  Quick question for you all.  My car has rapidly overheated (in 3-4 minutes) the past couple of times I have driven it. The temp gauge shoots up to about 220 and then I shut it off because, well... I don't want to ruin it. 
   
  I'm trying to track down the source. Water/Antifreeze is full and looks green and clean (no froth). Oil level is good. I pulled the top hose off of the radiator and ran the car up to 200 degrees at which point the thermostat opened and water came out. That's pretty much it. From what I've done I assume that the thermostat and water pump work (although 200 degrees is high for it to open I think). 
   
  Where should I look next? I have been planning on adding a row to the radiator, so I can do this, but I know that this isn't the source of this rapid overhating. Could the radiator be plugged somehow? Is there anything else I should look for? I know that these are pretty simple systems, so it could only be so many things...
   
  Thanks for the help!
   
  Matthew...
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  A bunch of people thought it might be a blown head gasket. Well, I finally got the compression tester I ordered three weeks ago on ebay (thanks for nothing, lazy ebay dude) and I ran a test and came back with 165 on 1 (from front of car), 175 on 2, 158ish on 3, and 170 on 4. Is this pretty normal? I guess I can cross head gasket off my list?
   
  Next, I pulled off the radiator and ran water through it. It seemed to flow fine from what I can tell, but it was just a hose I was using. I plan on redoing the radiator, but for now it doesn't seem to be a big issue.
   
  Then, I ran water through the block and the water looked pretty clean, was a nice light green color, and flowed smoothly.
   
  Next, I pulled off the radiator tower and got at the thermostat. It is a 180 deg thermostat, which I will replace with a 160 one. I boiled it and it started to open at 180 and was full open at about 200-205. 
   
  Finally, I took off the fan belt and spun the water pump by hand and it seemed to move water through it. Mind you, I had most of the water out of the engine by now, but when I spun it I would get a corresponding trickle.
   
  Soooo... That is where I am now. I haven't put everything together yet, but since I didn't really find anything "wrong,"  I suspect that I haven't solved the problem. Should I put everything together again and see what happens? Does anyone have any other ideas on what could be causing the overheating?
   
  Thanks again for all of your help!!!
   
  Matthew...
    

       
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