Flushed radiator and replaced thermostat. If sitting at idle the temp gauge barely goes up to 200. But while driving in the Florida heat with the AC running the temp gauge starts to go to above 200. If I turn off AC the temp gauge goes back to around 185. I tried to get air bubbles out of the system because that is what it acts like but i'm not having any luck.

What is the normal operating temperature for my truck?

Is there a good write up on getting air out of system? I noticed that the heat does not blow hot. I've read that this could be due to air too.

Thanks in advance for any help you give.

 

Mine does the same thing. When my ac is on my temp gauge will go up way above 200 sometimes. So I don't use it unless I'm on the highway. With local driving I turn it off that's when it seems to be the worse. I replaced thermostat. New fluid. Fan clutch. And still no help. I just got used to it no ac But with you in florida it's a problem. When you start driving do you hear the waterfall in the heater core?

 

Did you ever notice that thing in front of the radiator? It's called a condenser, It cools off the heat generated by the air conditioning. So of course the temp will go up because the air in front of the radiator is being heated up by the condenser. You don't really notice this that much until the temps go up and everything struggles to keep cool. Especially stuck in traffic.

If you drill a small hole in the thermostat it will allow the air to get out when you fill the system.

 

You want to drop that temp by 10-15* then run 60/40 water to antifreeze mix. Hell here in Florida you could even go 70/30. Not only is water much better at transferring heat than anti-freeze but the thinner mix will increase the flow rate.

Just remember you're giving up a little corrosion protection so be sure to use distilled water (you should be anyway)...

 

Thanks for all the input. Yes Moparite, I know what a condenser is but this is the first vehicle I've had, and there have been quite a few, that the temp goes up when AC is running. Every other vehicle the needle doesn't move. I may have to try the hole in the thermostat. I've seen others say to drill two small holes but I will start with one.

HammerZ71: I've never used distilled water always straight from the tap and I usually do a 60/40 split on the mix too.

When it cools off a little I'm installing the new dashboard and instrument bezel. I just didn't know if I needed to do heater core while i had the dash dismantled?

 

That could be your issue. Tap water contains trace minerals that over time leads to scaling and corrosion. Scaling is when these minerals adhere to metal surfaces in the radiator, tubes, lines, etc. This results in slow heat transfer and blocking of tubes.

The corrosion in the system is called galvanic corrosion and occurs when these trace metals and minerals are in contact with other metals. Aluminum is very receptive to galvanic corrosion. This corrosion releases rust from the introduced minerals and aluminum oxide from the radiator into the coolant.

ASE training 101. LOL...

 

Straight water cools better than 50/50 mix but not wise to use it. Those cooling system additives that are supposed to lower temp are full of crap(at least from the people the i heard that used them). One hole in the t stat will do just fine. You may try a 180* stat, That will help a bit.

If it's not leaking don't change it.

 

Yeah, straight water is much better for cooling, but is strictly for the track where cars are broken down and systems are emptied and flushed until the next race day.

Interestingly, it's the only application I've seen where surficants (Water Wetter, Purple Ice, etc.) show a measurable difference. I've seen Purple Ice reduce temps by 15* in straight distilled water. But never enough to see a difference in a coolant water mix. I think the chemicals in coolant prevent surficants from effectively decrease surface tension.

In the case of Purple Ice, it does contain some beneficial lubricants which can extend the life of the water pump. Can't hurt, but don't expect it to magically fix an inefficient cooling system...

 

I have an all ali radiator, 180°F Stant, e'fans, and run a 50/50 mix.
My temp sits in the 180-185 range regardless of what I'm doing, or what is 'on'.

As for the heater core; I'd change it, needed or not... a heater core is far cheaper than having to go back in later (even if it is your own time).

 

The folks on another forum I hang out on swear by Water Wetter. Especially in cars as 'cooling challenged' as third generation F-bodies. (camaros/firebirds)

If you notice the problem more at lower speeds, might consider going to efans. They aren't dependent on engine RPM to move air.