Strange Heating Problem on 2001 PT LE
 

Having a slight overheating issue that has me confused. We picked up this car in NW AR and "attempted" to drive back to TX. After about 80 miles is started getting hot so I pulled over and had it towed to a reputable shop in the next town. They checked for combustion byproducts in the coolant and all was good - thank the Lord! Cooling system would not hold pressure and issue was traced to a cracked thermostat housing. They replaced that and all was good so we hit the road again. After a couple hundred miles it started heating up again! Pulled over and called a tow truck and had it delivered to my house - $300 later... >:-| I looked at our repair receipt and didn't see that the thermostat had been changed so I took it to a neighborhood shop and had the thermostat changed and a flush and fill. This concludes the history portion of the issue, now, "The rest of the story..."

I found the local shop had not filled the radiator completely so I topped it off and put some juice in the overflow tank and thought I had it licked. I let it idle in the driveway with the AC on for about 30 minutes and the temp gauge stayed at exactly 1/2. Went for a spin the next day and the temp gauge came up to the 1/2 way mark and stayed there for about a mile then the gauge started slowly rising. I pulled over and the temp went back down to 1/2 and stayed there for a several mile drive. Got home and next morning check coolant level in radiator and it was full. Went for another drive and it started getting warm at exactly the same spot (give or take a hundred yards) and cooled back to 1/2 as soon as I pulled over. I then drove another 8-9 miles without issue.

The Cruiser currently has 88880 miles and looking at the CarFax report the the radiator and upper and lower hoses were replaced at 76,552 miles and the car appears to have been well maintained.

I've never had a vehicle that acted like this but I'm leaning toward maybe the fan or fan relay? Wen idling in the driveway I could tell the fan came on but I'm not sure if thee two speed function worked, or not.
I have the hard-copy service manual set for the 2002 PT Cruiser we had, years ago, and will dig it out and see if there is a fan test.

In the meantime any suggestions would be welcome.

Warped head. If the fan was an issue it would over heat while sitting still. The fan is only in uses when there is not enough air to flow across the radiator to remove the heat.

The shop checked for hydrocarbons in the coolant and found none. How would there be none if the head was warped? Also, why would the temp return to normal after pulling off the road for 30 seconds and then remain normal?

It is possible the radiator is partially clogged.

At idle, there is not much heat that needs to be removed. The fans are able to draw enough air flow to keep the temp under control. As the rpms increase more heat is produced and there may not be sufficient coolant flow through the radiator for the additional heat to be removed.

ggoose - Thanks for the suggestion. I can see that but why would the temp return to normal after a few seconds and remain normal if there was a partial blockage?

Watch my videos on youtube about how I check for a warped head.

Just an update, thought I'd already posted this...

This did turn out to be a warped head. :-( I had a friends uncle who is a mechanic at a Dodge dealer pull the head, I took it to machine shop and had it refurbed, and he put that head back on. Car ran great and also replaced lower control arms and sway bar bushings. Drives like a new car!

The old PT lives again =) I still have my 2001

Unfortunately Here is the "rest of the story." Early last week my wife was driving it up to Kroger for some groceries and a stupid b***h came out of a parking lot, crossed 4 lanes, and nailed her on the front corner of the drivers fender. Both airbags popped, ruptured the radiator, and looks like oil/transmission cooler, AC condenser,destroyed the bumper, bumper support, left front fender, hood and the passenger fender looks to be pushed back to where the door won't open. The airbag bruised her up pretty good but she is about recovered but mentally she refuses to drive. :-(

I'm afraid that the car is probably a loss so I am kicking around the idea of getting an early Cruiser with maybe a trashed drivetrain and swapping over my good stuff to it.

I turned everything over to an attorney and as soon as I get the go-ahead I'll start removing sheet metal to see what kind of "real" damage there is. You ever see what an air-bag deployment will do to the brittle PT dash? Not pretty...

well the pass side is designed to do just that plus the speed it comes out yeah