I've got a 95 Blazer 4.3. Replaced the water pump, themostat, lower radiator hose and cap. Still runs hot, but after replacing the cap twice, the coolant boils whenever the temp goes above 210. Seems like a pressure issue, but I don't know where to check at this point Any ideas? Thanks in advance.

 

Might want to flush out the entire cooling system incluing the radiator. Use a 50/50 coolant mix I am guessing so thats not an issue. Any bubbles coming out the the radiator at the cap?

 

Thanks for the reply. I am using 50/50 only. Figured I would use concentrate and DI water when the problem is fixed.

I'm not seeing any bubbles from the cap or around the filler neck. Even though I've replaced the thermostat I might swap it out again.

 

Can you squeeze the top radiator hose when it heats up, and feel if it has circulation? That would identify or eleminate the tstat.