Another overheating question...

My '01 Jimmy has been good to me in the past, but this summer it's been kinda crazy. If I'm at a light, I'll creep up to 230+ degrees in these hot summer days quite a few times, and that's not even with the A/C on! A few monthes ago I had the waterpump + thermostat replaced (thermostat was a OEM GM one, yea i know, not good!), and everything was great. I do not have any coolant leaks and my coolant level appears ok. My A/C is COLD and my heat is extremely hot, so I don't think my heater core is clogged again.  
 
Before I say its the Intake Manifold gasket, should I flush out the radiator first? I'm wondering if maybe it's clogged or something. Also, what do you think a shop would charge me to do the Intake Manifold gasket?
 
Thanks
 
Chris

Are you sure you have a leak? 

When was the last time the cooling system was opened up?  It is possible that there still could be air in the system, but if it has been a long while, then probably not...

Well when my heatercore was clogged some monthes back, I had my entire cooling system flushed and filled by my trusty mechanic. When it started overheating slightly last week I was a bit concerned, but we had some 99+ degree days so I wasn't too worried when it crept to 230, but now its getting closer to 260 so I'm sure something isn't right . After it got to 260 I shut it off and let it cool down. I had half a bottle of dexcool in my garage so I filled the rest of it up with water and proceeded to put some in the radiator. It actually let me put the whole thing in and the radiator was full after that. I was low on fluid but I'm assuming it was because my temps were sky-high.

I'm just wondering if when I had him replace my broken 180* thermostat with a factory GM 215* one if it took a crap. He said those factory thermostats aren't good at all. If it is broken and my truck is getting hot because of it, is the thermostat staying closed or open?

quote:

ORIGINAL: vagnozzi

1.I was low on fluid but I'm assuming it was because my temps were sky-high.

2.I'm just wondering if when I had him replace my broken 180* thermostat with a factory GM 215* one if it took a crap. He said those factory thermostats aren't good at all. If it is broken and my truck is getting hot because of it, is the thermostat staying closed or open?

1. Vice versa.
2. Why a 215 degree thermo? I think the factory replacement is 195 degrees.
Pressure test it for leaks, make sure the cap is good (use a Stant), use the right thermostat, and make sure the coolant level is correct.
 

The coolant level is now correct, and I'm still having the overheating issue. It was correct before I started overheating in the first place because I check it regularly. I'm gonna swap out the thermostat and when the system was flushed I had a Stant cap put on, the factory one let air in
 
I really hope its only the thermostat, the motor runs perfect for 124k miles

Okay, but get it pressure tested. Coolant doesn't just evaporate inside a closed system. It's been going somewhere.

*update, truck is in the shop now, I find out in a couple hours where its leaking* pray that its not a head gasket!

Pray it is not the heater core.....Just swaped mine because it was leaking....pain in the azzzzz