PT Cruiser Overheating

[evonna_21]

PAST

I have a pt cruiser, 109,000 miles that has no check engine light. Over the holidays on the way to christmas dinner I broke down, 800 miles from home. Was told I needed a new waterpump by a mechanic where I broke down. The radiator was losing fluid so I would have to replace it with water which Is how I made it back home. Got home, had a mechanic replace the following:

water pump, timing belt, camshaft belt tensioner, camshaft belt idler, spark plugs, wires, thermastat and anything else related to timing job. Fan had already been replace before that. Didn't not replace radiator because said it was ok.

Car was running okay but every now and then I would hear like the bubbling sound while In the car once I would park the car. I had heard the bubbling sound months or a year before I got stuck on the road. Asked about sound before didn't get no definite answer to that.

RECENT

Recently, I did a 100 mile trip and the car overheats. Put water in radiator and was able to get home. The only thing that I think saved me was the breeze from air and the fan kicking in.

I took it to a mechanic he runs a pressure test on it. Says pressure was ok, ran it a long while but couldn't get it to overheat. He thought maybe it could be my heater coil but he couldn't the heat coil to overheat or something.

Other than he didn't know what was going on with it. He suggested I replace the radiator cap and I did with one that has a lever on it.
Since my old cap was so messed up he suggest I drive it a 100 miles or so to see how it ran and/or to be able to check again for a defect in heater coil.

So, today I drove another 100 miles. 50 miles up and 50 miles back. I made sure to drive 65 to 70 speed. It was extremely bubbling when the car turned off when I arrived at my destination.

I was going to try to take cap off. I lifted the level on radiator cap but then the water bottle starts spitting out fluid. It was ovrrflowed. So I just put the lever back down on the cap and never took the radiator cap off. Drove straight to repair shop. Mechanic states the radiator was cold but car was overheating til the point he couldn't touch it. They're closed for weekend so he will look at it again. I mainly use the car for errands so I don't have to have a lot of speed going around town but I think this was my second big trip.

I'm really confused at what's going on with this car. Anyone else experienced this?

[ptcruisersteve]

When an engine overheats it can damage the thermostat. I would recommend checking the thermostat to see if its working properly. If the radiator is cold but the engine is hot then your coolant is not circulating properly.

[chuzz]

I agree with Steve. If it were mine, I'd replace the thermostat first. What pressure is the radiator cap rated for that you put on it? I had a bubbling problem with mine after moving to FL and replaced the thermostat and put an 18 lb. rated radiator cap on it. I haven't had a problem since. Be sure to check the rubber hose from the filler neck to the over flow bottle. If it has a crack or hole in it, that can cause overheating and bubbling too.

[evonna_21]

Thermostat was replaced during timing. Mechanic said when he did the pressure test it was working properly and didn't need to be bleed because that's what I thought it was but the pressure test said that wasn't it.

[JDK52]

As has been recently posted -
What you are describing most likely is a faulty thermostat.
It is possible that the "new thermostat" is defective.

Replacing the thermostat again is a good next step.

Good luck and your updates are appreciated.

Always nice to hear of a problems resolution.

[LionPT]

Originally Posted by evonna_21

Thermostat was replaced during timing. Mechanic said when he did the pressure test it was working properly and didn't need to be bleed because that's what I thought it was but the pressure test said that wasn't it.

A pressure test can't tell if the thermostat is bad or not...it basically is looking for a leak in the system.

[wb2kki]

I would not assume anything and treat the symptom like it never happened. Even get a second opinion.
If possible with infrared thermometer check the temp.
Since the car has overheated a number of times I would consider a blown head gasket or warped head. You can by a kit to check gases in the coolant or have your mechanic do it.

Good luck

Mike

[evonna_21]

I talked to the mechanic and there is air pockets in the coolant. If it is a blown head gasket or warped head how much should it cost to fix those?

[OurPTGT]

If I missed it sorry. What year/model?

[rsrocket1]

It may be that the coolant was never filled and bled properly. If the thermostat does not have a jiggle pin in it, there is no way air can leak out once the thermostat is closed. If you have a shortage of coolant in your system (because of the trapped air in the filler neck), the pump may have a tough time pushing the coolant up the neck out to the radiator. Of course the air is now hot and compressed so when you try to take the cap of, the air pushes any coolant at the top of the system out the cap making you think the cooling system is full. But in reality, once the initial gush of coolant comes out, if the thermostat stays open, you might be able to fill upwards of 2 liters of coolant back into the system (how do I know ).

You either need to know yourself or have a competent mechanic bleed the air out of your cooling system using the bleed valve and just as important, make sure the thermostat has a jiggle pin on it. Here's what the pin looks like, just the pin, not the real PT thermostat. The proper thermostat has a rubber gasket around it.



Getting to the thermostat involves removing 2 bolts from the plastic filler neck and lifting it up.

Once the mechanic has properly bled the system and topped it off, it's up to you to check the coolant reservoir after the car is cooled to make sure the coolant is at the right spot and add distilled water (or coolant mixture) if it is low when the engine is cold. You should do this first thing in the morning before you drive. Sometimes it takes a couple of days to get the last bit of air out and the engine will suck coolant from the reservoir as it cools down.