Verification on overheating issue.

[PT_Preacher]

Ok, here is my long- overdrawn story.

I bought my PT new in 2005 in CA. Great car, no major repairs. That is until moving from NV to CT two years ago. Once I got our here, my car really started overheating every single time I turned the A/C on high (weird that it happened in cooler but muggier CT and not the Mojave desert). So, I did what everyone expects: Thermostat, radiator cap, coolant flush, new fan, and finally new A/C compressor (I did change the belt at the same time).

Last summer, everything went smooth. This summer, we have the exact same issue. It is only happening when the A/C is on EXCEPT for Wednesday, when it overheated a second time after I had already turned the heater on full blast.

I also want to note that if I turn the heaters on full blast for like 2 minutes and get up to speed, it drops right back down to regular temperature real fast, you can watch the needle nose dive.

I only have three areas I am suspecting in this order. 1) fan. I replaced it before, but maybe I have a wiring issue. I can manually turn the fan on by turning the gauge to the right. Maybe it isn't always engaging in the A/C position. If this is the case, anyone have a clue if the PT even has a Fan regulator and where it is, I'd guess it would be controlled by the master comp but could be wrong. 2) Maybe I got a second bad thermostat. Thats only a $10 repair so I like that idea. 3). maybe my water pump is just on the very very edge of failing. I SHOULD have replaced it back when I did the belt, but didn't know better. That would be like a $50 repair, but lets face it, a week's worth of work.

I'm just about to tear out and repair a shower at my house, so before I go spending time I need to get a second opinion. Proverbs 15:22 Without counsel purposes are disappointed: but in the multitude of counsellors they are established. Thanks for any input.

[NitroPT]

The fan is PCM controled

The water pump is shaft driven, it either works or is doesn't.

Your heater on solutions discribing water to air circulation augmenting.


Have you rinsed you raditor core, trans cooler and AC condensor lately?


Also it really helps to tell us what model your PT is!

[ptcruisersteve]

Have you always used HOAT coolant?

[ptcruisersteve]

You might want to check the hose between the thermostat housing and the expansion tank. If there is a leak then you may have air getting into the coolant system and that can cause overheating.

[PT_Preacher]

Thanks for the replies.

I have always used HOAV exempt one time for about 2.5 miles. My wife overheated and I took off to go help her. We went to an Advanced Auto parts that was in the plaza she pulled into and grabbed some coolant and just drove it home. When I got home, I realized it was the wrong stuff and did a bleed.

What I just found out, after reading my Haynes manual, was about bleeder valve. I've never had a car that has a bleeder on the coolant before. I opened up the radiator cap and at running temperature and the coolant is just above the thermostat, lower than the arc on it. I did notice a constant stream of bubbles coming up. So, it sounds like I have air in my system, eh?

Does anyone know the right up to this? Do I just put the hose and pump on the bleeder valve? Also, is this the right level for the radiator? Now I'm all paranoid. The reservoir tank is still full, but shouldn't there be enough coolant to get to the upper radiator house (Logically speaking).

Thanks again for the help, guys. Just like most of you, I've always joined the forum of those cars I've owned. This forum is usually the quickest and nicest out there.

[ptcruisersteve]

Originally Posted by PT_Preacher

Thanks for the replies.

I have always used HOAV exempt one time for about 2.5 miles. My wife overheated and I took off to go help her. We went to an Advanced Auto parts that was in the plaza she pulled into and grabbed some coolant and just drove it home. When I got home, I realized it was the wrong stuff and did a bleed.

What I just found out, after reading my Haynes manual, was about bleeder valve. I've never had a car that has a bleeder on the coolant before. I opened up the radiator cap and at running temperature and the coolant is just above the thermostat, lower than the arc on it. I did notice a constant stream of bubbles coming up. So, it sounds like I have air in my system, eh?

Does anyone know the right up to this? Do I just put the hose and pump on the bleeder valve? Also, is this the right level for the radiator? Now I'm all paranoid. The reservoir tank is still full, but shouldn't there be enough coolant to get to the upper radiator house (Logically speaking).

Thanks again for the help, guys. Just like most of you, I've always joined the forum of those cars I've owned. This forum is usually the quickest and nicest out there.

First you let it cool off. Open the radiator cap and fill up the coolant to almost the top of the top hose coming from the radiator. Let it run to normal temperatures. You will see bubbles coming out and this is the burping cycle. Turn on the heater to get the full coolant system circulating and after you don't see anymore bubbles then fill up the radiator with coolant and put the radiator cap back on. Make sure you have coolant in the expansion tank. After you let it run for a few minutes there is a bleeder valve below the thermostat housing. Put a plastic clear tube on the end of the bleeder valve to keep the coolant from getting on anything below. Take an open end wrench and open the bleeder valve until you start to see coolant running out of it. Keep it open until you don't see anymore air. Please don't forget to check the hose from the thermostat housing to the expansion tank. If its leaking you have wasted all this time doing the burping cycle and the bleeding.

[ptcruisersteve]

Does your radiator fan turn on immediately after you turn on the A/C?

[PT_Preacher]

Thanks for your help. I did try and bled the system. The radiator fan does turn on when I hit the a/c. I had the a/c on full blast in the garage Saturday for over a half hour, temperature looked great.

I caught a bad case of poison ivy, so I haven't had the ability to test drive it yet, but again, thank you for the advice.

[NitroPT]

A few interesting corrections and thoughts?

The coolant recovery or reservoir tank has nothing to do with cooling unless your system is heating up enough to lose coolant and not be able to recover the lost coolant. Vehicles ran without recovery tanks for years.

That is why your grandfathers taught you to always check the fluid level in the "radiator". Now you tech your kids to check the level in the coolant reservoir tank.

The coolant tank is NOT a sealed unit and air comes and goes . So with this in mind atmospheric gases such as nitrogen will form in H20 forming air bubbles which is constantly exchanged in the cooling system.

A coolant reservoir hose that is leaking means it is going to leak fluid. It will also limits the coolant recovery system to work properly.


Bleeding the cooling system is a very simple procedure but as I keep repeating responses expressed on PT Cruiser forums as complicated and apparently reported to be generally unsuccessful. IMO this has always been shown to be inaccurate reporting. The system will self bleed if the engine is brought to temperature and cooled at least once definitely twice. It is simple physic's. IMHO if you stick with the bleeding as your problem you are wasting time finding the real cooling problem.


The use or none use of HOAT coolant has never proven to be detrimental to the temperature control of the PT Cruiser if the chosen coolant is introduced in the cooling system properly.

There are warning about improperly mixing incapable coolants which should be adhered to.