Bad Radiator Fan?

[Flash619]

Two days ago I had a bad overheat condition with my PT. I went to pull out of a parking lot and found myself with a bad rough idle, I checked and my temp gauge was maxed out. Very scary and I shut the car off ASAP and waited for it to cool (and the coolant to stop boiling).

Today I had a chance to look at my PT. If I turn it on cold, and turn the AC on, I barely feel any air move behind the radiator fan. The amount of air force is comparable to that of a gentle breeze. Blowing air lightly on my hand has the same feel as the air from my radiator fan did.

Needless to say, I assume it should push more air than this?

A bit of backstory, typically this radiator fan had issues where the low rpm would not engage. This would make the AC not work unless I was in motion. To fix this temporarily I removed the low fan relay from the fuse box so it would run on high all the time... now it seems to barely do anything. Is it possible it's just burnt? Any good ways of testing this?

Thanks!

[ptcruisersteve]

Originally Posted by Flash619

Two days ago I had a bad overheat condition with my PT. I went to pull out of a parking lot and found myself with a bad rough idle, I checked and my temp gauge was maxed out. Very scary and I shut the car off ASAP and waited for it to cool (and the coolant to stop boiling).

Today I had a chance to look at my PT. If I turn it on cold, and turn the AC on, I barely feel any air move behind the radiator fan. The amount of air force is comparable to that of a gentle breeze. Blowing air lightly on my hand has the same feel as the air from my radiator fan did.

Needless to say, I assume it should push more air than this?

A bit of backstory, typically this radiator fan had issues where the low rpm would not engage. This would make the AC not work unless I was in motion. To fix this temporarily I removed the low fan relay from the fuse box so it would run on high all the time... now it seems to barely do anything. Is it possible it's just burnt? Any good ways of testing this?

Thanks!

You can test the radiator fan by applying 12 volts from the battery to the plug going to the radiator fan.

Since your low speed has most likely failed on your radiator fan I would suggest replacing the radiator fan. Considering the cost of replacing the head gasket can be expensive compared to an estimated $85.00 for a radiator fan I would order a new radiator fan immediately. I have kept a brand new radiator fan in my garage in case the radiator fan fails in one of my Pt Cruisers. I have never overheated the engine as I don't take chances with any part of the coolant system not working properly.

I am also thinking that your engine light is on all the time with the low speed relay being removed triggering P0480. This is not a good idea as you will not know if you start to have other problems with the Pt Cruiser unless you use an OBDII Scan Tool continuously. This can leave you walking.

[Flash619]

Originally Posted by ptcruisersteve

You can test the radiator fan by applying 12 volts from the battery to the plug going to the radiator fan.

Since your low speed has most likely failed on your radiator fan I would suggest replacing the radiator fan. Considering the cost of replacing the head gasket can be expensive compared to an estimated $85.00 for a radiator fan I would order a new radiator fan immediately. I have kept a brand new radiator fan in my garage in case the radiator fan fails in one of my Pt Cruisers. I have never overheated the engine as I don't take chances with any part of the coolant system not working properly.

I am also thinking that your engine light is on all the time with the low speed relay being removed triggering P0480. This is not a good idea as you will not know if you start to have other problems with the Pt Cruiser unless you use an OBDII Scan Tool continuously. This can leave you walking.

Thank you, I appreciate the help. Yes it does throw a P0480. Today I did some testing and here is what I found out.

• After re inserting the low rpm relay. The fan does engage when the AC compressor engages.
• When the low rpm relay is removed, the fan does not turn at all. Even with the engine temp at 50%, the fan does not turn.
• After swapping the high rpm relay with the relay for the horn, the fan still does not turn.

So from what I can tell, either the radiator fan is burnt out, the wiring is bad, or the ecu isn't sending a signal to the relay to engage.

I'm a bit confused however because it doesn't make sense that the fan would not turn on high if it turns on low. Low speed still accepts 12v and simply passes it over a resister to lower it to 6v (correct me if I'm wrong here). So in theory, the fan on high is just receiving the direct 12v connection. In that sense, the motor itself would have to be dead, but then I would think neither high or low would function. Right?

[LionPT]

The fan motor has 4 brushes...most likely 2 or more are gone.

[ptcruisersteve]

Best thing to do is to disconnect the radiator fan plug and apply 12 volts to the low speed and high speed one at a time. Until this is done you will be guessing on why the one speed on the radiator fan is not working.

Radiator fan brushes.jpg

Diagram below is for a 2001 Pt Cruiser.
Schematic-PT-Cruiser 2001 radiator fan circuit.jpg

If the radiator fan is working properly on both speeds when you manually apply 12 volts I would suggest checking fuse#5.

[funkyfred]

I am on my 3rd radiator fan.

It is relatively easy and fast to replace. I can do one now in about 30 minutes. Your first time may take a little over an hour. I think you only needed an 8mm and 10mm socket + something to clamp down the coolant hose to make sure you don't spill any.

Go to www.rockauto.com and order yours asap. Sure you can find out what is wrong with it and possibly only replace a relay but... my time isn't worth the diagnosis. If you remove the relay found at the very bottom of the fan (you can reach it by just laying on the floor) and plug it back in, most likely it will start working again... only to fail a few days later.

First time I replaced the fan, it lasted 4 years. I just died on my again a few weeks ago. I'm sure others are more educated and can actually figure out what is wrong with the fan. (If you do buy one, you need to find out which fan you have. That can be done by counting the relays on the fan itself. I believe my 2006 had 4 relays

[Flash619]

Just wanted to post an update.

I installed a new radiator fan last Saturday and everything has been perfect since!