I've replaced the rad, the t-stat, and upper rad hose. I'm car is driveable for about 10-15 miles then it starts to get hot (I pull over immediately).

The water pump is working, and so is my fan. My coolant is actually going back into the overflow tank and NOT cycling back into the radiator (SOMETIMES when its completely cooled is goes back, but not always)

I understand the most common issue is something as simple as the cap. I actually REPLACED the cap and it STILL was overheating (I'm thinking its a bad cap because the FIRST t-stat I bought WAS defective).

Say when I get my new cap (I put my old back on the new one is even worse, doesn't seal, and its the right one) I still overheat.

What could possibly be the next thing to look at? Mind you water pump DOES WORK, NO LEAKS, and its NOT the heads (did a pressure test and others).

Ideas????
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~Miann

You've done a flush lately?

yes I have

what was wrong prior to replacing things? whats the history on this? were you low on coolant before and it was over heating or did it just suddenly start overheating and everything was in perfect working order? have you confirmed that its actually overheating and not just a faulty temp sender?

explain how you did your flush.

your channels could be clogged??? or the temp sensor

then use the stickies to find the CEL post to check if your temp sensor is bad

I'm Thinking you water pump is out. Its just free spinning and the blades are actually not rotating. Until you take it off and verify that it is working, its most likely your water pump atm. Remember to fill with 50/50 or mix 100% with distilled water. Don't be cheap and fill with sink water.

what other test did you use for the internal leak other than the pressure test?

have you used this?
http://www.arrowheadradiator.com/head_gask...n_leak_test.htm

You flushed it recently? I bet you've just got air in the system. Run your car for a few minutes with the radiator cap off, you need to burp the system. Air in the system will cause it to overheat. Don't forget to shut it off before you replace the cap though, just for safety purposes.

>
Yeah bleed the air out of your system and if the problem is still there then do a sniff test
as it looks like it's a head gasket problem