I have a 2007 chevy equinox with about 160xxx miles it's an ls model. It has a closed radiator system. I had a issue that appeared to be a closed thermostat. I replaced it and bled the system for about an hour seemed ok. However now when I'm driving the ect temp goes up and down between 185 and 210. I put a 195 thermostat on it. The problem is when I stop for a minute or more the temp gets above 220 until I start moving again. People have told me many different answers such as the water pump, maybe a bad thermostat again, bad cap, head gasket. The fans seem to be on and running when I turn the car off. I need help!!! I don't see oil in coolant or coolant in oil either
I agree with previous response and that'd be the first step but also reqd my post below about inspecting the intake bolts.
These are notorious for several sources to cause overheating. It is usually either heater core or front driver side upper intake manifold bolt. The bolt actually walks out some and causes it to leak. It wasn't torqued correctly at manufacturing and they ALL do it. You can't retorque it and it starts at a very slow leak. If these things overheat once, either it blows the head gasket or the intake gasket. Just the littlest air pocket will do it.
Look at the lower intake bolt by the thermostat housing on the driver's side. If its wet, then the bolt has already walked out and damage already been done. At this point you go all the way to the heads because those gaskets are junk.
If you're comfortable working on cars, it's an easy job to do the head gaskets because there's a lot of working room in it. ( my wife has an 07 and I've dealt with same issue couple years ago. Overheated once and had to do the head gasket).
If its the heater core either you remove the entire dash (correct way doing it) or it is easily accessible through driver side console but it requires some modifications. You'll smell coolant inside the car and carpet will be wet. If this is the issue and doesn't overheat again after repair then you shouldn't need to change out the intake or head gaskets.
If you're not handy at cars then toss out this car. Not worth paying someone to do it. Min. $2,000 for either job
replace the pressure cap if it's original.
check the front of the water pump for weeping.
make sure the radiator fins aren't full of dirt and debris.
and what about the coolant itself? Is it clean? Have you done a complete replacement lately?
when I stop for a minute or more the temp gets above 220
when you stop moving, air is no longer being forced through your front grill, and the fans are doing all the work of cooling the radiator, so they need to be working at full capacity. If your temps go high, All the fans should be coming on a full speed.
https://www.youtube.com/@scottykilmer/search?query=overheat
