another overheating problem.....
 

Good morning everone, this has me baffled. I think I have checked everthing. Here is the list and please tell me if I have missed anything.
Replaced thermostat.(195)
checked fan ( low speed on at around 190 degrees...high speed at around 205)
radiator checked for clogs, leaks and any contaminates in fluids, all check good. Using 50/50/ antifreeze (all new antifreeze)
Checked for head gasket damage, no leaks or steam/white smoke coming out tailpipe. nothing in the oil.
Water pumps seems to be ok, not leaking or making a noise.

So here is whats happening:
Start it up and let it just sit an idle, temp gauge goes up to around the R and stays, then rev up engine to about 2000rpms let stay and temp gauge starts climbing( with AC on , or with Heater on or with nether on, still risestowards the L.
Take out on highway, tem gauge slowly rises just crusing and eventully gettin on or near the L. if put it under a strain,(climbing or running it a little hard) temp gauge goes up faster. But if I have to stop at a red light or let it just idle witout moving, temp gauge starts to go down.
I have been trying to burp it but so far it is a slow process an each time I check it after cool down it needs more, and yes I have been filling it from the tube with the small screw.
Could i just not have all air out yet? I have thought about taking it to ford dealership to have them get all air out.
Also my tune has most computer checks turned off, so I don't think putting it on there diagnostic machine would help.
I may have to take to the shop that tuned it an go from there if I don't get some answers that might help, but its a ways off from where I live.
thanks in advance for any solutions and ideas.

Cobra has 60,000 miles on it.

Does it ever puke coolant ?

How did you determine you don't have a head gasket problem. It's actually the head bolts that are a problem on sc applications and open track use.

I was thinking the same thing, blown head gasket.

thanks for all of the replies, so here is quick update:
Took it to local Ford dealership checked for head gasket problems...it cleared. Then checked for air in system, ended up having an air lock in it so they dumped the fluid, put new in and used the vacuum on it and it looks like it corrected the problem it now runs around the "M".

Cooling problems
 

A couple of hard rules with these cars and cooling problems (for you and others).

1. Don't trust the original gauge! They are very inaccurate and R is not the same temperature on every car. So, R might be normal to me but M is normal to you. If you suspect a cooling problem or ever go to the track, get an aftermarket gauge! Autometer makes a cool gauge cluster that allows you to add two gauges that fit in the regular cluster area if you don't want an A-pillar pod or other dash pod. There is an adapter out there that makes this very easy. Oil pressure on the other side.

2. If it doesn't puke coolant, it's NOT overheating! IIRC, the high speed fan doesn't come on til about 230 (or when the AC is on) and that's pretty hot.

3. You have to follow the coolant fill procedure that's in the manual (and on the interwebs).

Beyond these, you would also want to actually test the thermostat. I even test brand new ones before they go in. On the stove in a pot of boilng water. Use tongs and oven mits. :)

Compression test is really needed to check the head gaskets.

Enjoy your Cobra!

Thanks, Jimmy for the info, they did do a compression check (they said)and the tstat has been changed.