Good news about a bad Radiator Fan

[photo_doug]

I usually just gleen information from the incredibly knowledgeable people on this forum but I thought this time, I might be able to contribute.

About 2 weeks ago, my wife’s 2001 PT started over heating. About 15K miles ago, the radiator was flushed and an interesting bronze coolant (BG I think) added by the local garage.

I changed the thermostat ($12), reflushed the system, tested the rad and added standard glowing coolant (will be changed to the forum recommended stuff as soon it can be found) and a new radiator cap ($15). Car would operate to normal temp without a problem. Moving, it was fine. Sitting in traffic would overheat it. After research, I tested the fans by removing them and hooking them to a 12V supply. High and low speed operated fine. I tested the input and output voltages of the relays. They seemed to be working. I did replace both relays just to cover my bases ($20). I took the old ones and rigged up a little circuit so I could manually operate the relay in lieu of the computer while they were installed in the PDC. The relays were indeed switching but the fan would not come on…strange cause it would run when connected directly to the 12V.

When I ohmed out the plug on the motor, both high and low read about .5 ohms. I figured it was a coil on the windings so that should be right. Local O’Reilly’s had a replacement (Siemens VDO) motor ($105). I compared the ohm readings between the old and new motor. They were exactly the same. The shaft even turned with about the same resistance. When the new one was reconnected to the fan relay circuit, it worked great. Although, the high and low speed seem to be very close to each other (if there’s even a difference at all).

I think the 12V PS I was using was strong enough to make the old fan turn but for some reason, the car circuitry wasn’t? No fuses were blowing. The relays were just not able to turn the old fan.

Hope this will be helpful. This is a great forum.

[quicksilverdon]

Fan would work, but only when you directly applied 12V, not when in car normally?
Peculiar. Maybe problem was intermittent?
Well, at least new fan works - imagine if you had the same problem with new fan - you'd be pulling your hair out!
What did connector look like? Clean? Some have said that was their problem.

[CREWZIN]

On mine (2001) there's a heck of a difference between low and high speed fan operation. Low I can hardly tell it's running and high creates such a higher noise between the motor and moving air that it's impossible to miss that it's running. I'd estimate it's running about twice the speed when it's on high.

[vtmdsm27]

Yeh, first time I heard it I thot something was wrong. I checked this forum and read what others had to say

I had to replace the fan assembly for my daughter's 2007 PT. Cured the problem - perhaps there's a circuit issue on the OEM assembly? We used an aftermarket since the OEMs were not available (does that give anyone a clue?)

[photo_doug]

There is a difference in the fan speeds on the new model. Not sure of the amount but you can hear it change pitches. When I tested the old one, there was a very distinct difference in speeds. As long as the new one doesn't blow the fuse on low or high AND it doesn't overheat, it's a good fan . I disassembled the old motor. The brushes are worn almost completely out. That's probably what was causing the intermittent operation. It could be cleaned up and the brushes replaced. Be a bit of work if you could find the replacement brushes. I thought I read somewhere that you could get these but wow, that would be a lot of work...and then you'd have an old motor with new brushes.

[photo_doug]

ARGH!! Her PT went overtemp'd today. Once again the fan refused to work. When it got home, I disconnected the relays and tried my special manual circuit. The relays would not turn on the fans, despite the fact that they did have 12V on the feed to the fan upstream fan connector. Very frustrating. I thought maybe the new fan motor had gone south. I sprayed contact cleaner into the fan connector and made SURE they had good connection. Maybe it had some grease that was causing it not to complete the circuit. Now everything worked ok. Only time will tell. *hitting my head on the dashboard*

I've also seen where the head can easily warp due to high heat. the car has never been driven during max temp but how likely is this??

[quicksilverdon]

You may have had a connector problem all along...
I think if you don't drive long after light comes on you should be okay - if light is flashing then definitely stop the engine.

[Gabby]

Originally Posted by vtmdsm27

Yeh, first time I heard it I thot something was wrong. I checked this forum and read what others had to say

I had to replace the fan assembly for my daughter's 2007 PT. Cured the problem - perhaps there's a circuit issue on the OEM assembly? We used an aftermarket since the OEMs were not available (does that give anyone a clue?)

guys... I'm new to this forum, my daughter drives an '07 cruiser and she started having temp problems about 3 months ago. As long as she was moving, she was ok.
I was reluctant to go purchase a fan cuz it didn't seem to be the problem...(thanks to info provided here on the forum)we tested the motor with wire and the fan went on no problem... the problem was intermittent.
Well... not sure that it's the case in all situations, but we found the connectors to be bad... check the connection...play with it a littlemaybe the contacts are missing on yours too...
Hope this is helpful for some....

[VOETOM]

Doug,
I have the brushes, a little expensive . The good thing is the motor commutator has virtually no wear so I feel pretty good about being able to save it with the new brushes. Too bad they are not really cheap.
Tom

[rigger45]

I have had the same issues with an 01 non turbo. It has no faults indicated for codes. Both checks done. The fan will not engage with or without the A/C on. Everything checks out with the relays. Could it be a connector problem. I changed the fan motor about a year ago. The fan worked for quite awhile and then,,, poof it quit.
Just over a week ago, the system went south. Radiator was blown. We were stopped. New radiator, thermostat, etc. And it checked out at the shop we had it in.
But the situation seems similar. Any guesses that it may be a connector? I am also going to set up jumper wires to the connector at the fan itself to see if it works with separate 12 volt directly to it. If so is it OK to bypass and set up a three position switch to run the fan?
I say again. I am getting no faults on the key check sequence.