Weird over heating

[S13drifthatch]

So I need help with a rather unusual overheating issue.

I have a 91 twin cam and it's been overheating
I was in the drive thru and it started getting real hot not off the charts quite
But close. So I left and started driving and as soon as I got on the freeway it cooled down. Ok, so I have a bad fan or something. Of course it cools at freeway speeds. Nope, I got back to my house turned it off, let it cool. And at this time I opened the radiator cap and started the car. Let it warm up, water flowing nicely through the rad. and when the car gets to normal op temp the fan kicks on. It didn't over heat after adding a little coolant and burping the system it sat stationary for about 10 or 15 mins, running. I then took it around town here and there driving normally. And as I'm coming back home after a while of on and off driving. It started to heat up again then got on freeway and it cooled off. Got off freeway to house and it was fine at a couple stop lights then got home no issue.

Now one thing I would like to say is the first time I brought it back home and let it cool. The upper rad hose was pinched or vacuumed and when the car heated up it got normal again.

So basically it overheats randomly not really all the time or during regular operating conditions.

Any help appreciated. Thanks.

[Rich260z]

how stock is your cooling system? what was the last thing (if anything) you changed before it started having this problem?

Sounds like a thermostat or air in the coolant issue

[S13drifthatch]

I just got the car a couple days ago. It all seems pretty stock nothing upgraded. Was prolly gonna get a new thermostat. And burp the crap out of the system.

[anti tyler]

You need to jack up the front end and burp your system. Sounds like you've got some major air bubbles in there.

You can get a new t-stat if you want, or drain your system boil yours and see if it opens. or just evacuate the air and see how it does.