Cooling System Troubles...

[berry03]

Hi gang,

I got a 03' turbo s, and for some reason the cooling fans for the radiator don't work. When I turn on the car the one for the ac kicks it on I believe but then it goes off. I notice durning stop and go traffic the temp gauge on the dash goes to red. I already checked the fluid level and that's good, what else could there be? A VW specialist said there's a electrical gremlin in the black box above the battery that needs to be changed. $600, yikes... Could there be a simpler soulution, and less costly

[Oh Randi]

There are a few things it could be, but I don't think ANY of them cost near $600. If your fuse box on top of the battery melted, there are lots of threads on here with cheaper fixes. DO a search, they're everywhere because that is a common problem.

[berry03]

Originally Posted by Oh Randi

There are a few things it could be, but I don't think ANY of them cost near $600. If your fuse box on top of the battery melted, there are lots of threads on here with cheaper fixes. DO a search, they're everywhere because that is a common problem.

Sweet, thanks..

[berry03]

Ok, so I took a peek under the hood, to see if the fuse block melted in any way. NOPE

Ok I thought I read somewhere that there are a couple of sensors or relays that go into either the radiator or piping for it. Could these be the problem? If so where are they located?

[Smileybug]

Take a peek in this thread: Summer's coming/is here - check your fans!

[IndyTom]

What black box are you talking about? Either way it should not cost $600 bucks. If the fuse panel above the battery compartment isn't melted did you at least check the fuses?
Could be a variety of things including the fans themselves or the Fan Control Module or any of many sensors. I would have it scanned or Vag Commed to see what the exact problem is or you will replace items that don't need replacing and stil have the same issue.

[MyOtherRidesAVette]

If your trying to do this work yourself, here are the cooling system diagnostics from the Bentley. Checking the fans and fan conrol module is alos covered.

Bentley Cooling System Diagnostics
Overheating problem

Bentley drain and fill procedure
Beetle overheating

As to the main fuse box atop the battery, did you know what you were looking at and what you were looking for? This is the type of damage you are looking for.

From this thread -
Need input on fuse block on top of battery melting again...




Or, from this thread -
MORAV needs some help helping someone else on the Org! - Battery Fuse Box Issue


There are no DTCs (diagnostic trouble codes), being thrown?

MORAV

[berry03]

I did'nt see any of those types of burnt fuse action in the fuse block above the battery. But What I did do was the switch or sensor that goes in the coolant piping for the big radiator fan. I disconnected it and used a jumper wire, and voila. The fan goes on imidiatly. So would that mean that it's the switch or sensor that's bad? there is obviualy power going to it.

[MyOtherRidesAVette]

Originally Posted by berry03

I did'nt see any of those types of burnt fuse action in the fuse block above the battery. But What I did do was the switch or sensor that goes in the coolant piping for the big radiator fan. I disconnected it and used a jumper wire, and voila. The fan goes on imidiatly. So would that mean that it's the switch or sensor that's bad? there is obviualy power going to it.

I'm not clear on what you were jumping. You state "switch or sensor", which is it? The thermoswitch is tested by jumping the terminals on the plug connector for it. The cooling temperature sensor is tested by reading resistance across specified terminals. Refer to Bentley diagnostics I have posted above.

M.

[berry03]

Originally Posted by MyOtherRidesAVette

I'm not clear on what you were jumping. You state "switch or sensor", which is it? The thermoswitch is tested by jumping the terminals on the plug connector for it. The cooling temperature sensor is tested by reading resistance across specified terminals. Refer to Bentley diagnostics I have posted above.

M.

I.m guessing then it's a thermoswitch, cause it don't screw in to the radiator. The only thing is it has a 2prong wiring harness that plugs into the switch. The pictures or the info in the Bently diagnostic mentions its a 4prong??

[IndyTom]

Originally Posted by berry03

I.m guessing then it's a thermoswitch, cause it don't screw in to the radiator. The only thing is it has a 2prong wiring harness that plugs into the switch. The pictures or the info in the Bently diagnostic mentions its a 4prong??

Is it this switch? Home Page > Search > Thermal Switch > ES#248948 2-Pin Thermal Switch - 112C* - 357919369F

This is the switch that gave me problems. In my case the fans were running on Super High Speed as soon as I turned on the ignition and didn't turn off until I shut off the car. This little switch was all it took to get things back to normal. It is located up front where 3 cooling hoses/pipes come together.

Or perhaps you have a faulty Temp Sensor. If you still have the older "Black" style sensor switch it out with the new and improved "Green" Temp sensor:
Home Page > Search > Green Temp Sensor > ES#8485 Coolant Temperature Sensor With O-Ring - 059919501AKT

The Switch that screws into the radiator itself is the Auxiliary Fan Switch which come in different heat ranges and for different connectors depending on your car.
http://www.ecstuning.com/Volkswagen-...ch/Fan_Switch/

Hope that helps.

[berry03]

Sure loks like the first switch, and you described the location perfectly! The location is just a little to the top and maybe in between the 2 fans, but it sits in a plastic housing with 3 hoses that connect to it.

[IndyTom]

Originally Posted by berry03

Sure loks like the first switch, and you described the location perfectly! The location is just a little to the top and maybe in between the 2 fans, but it sits in a plastic housing with 3 hoses that connect to it.

YUP, that's the one! They are prone to fail and very easy to replace. Make sure if you order one that you order a new O-Ring as well. The switch doesn't come with one and mine really needed it. After replacing that little switch my fan operations returned to normal.

[berry03]

Sweet! But now the next part. How do you take it out Looks like the green clip that holds it in you move it to one side, was that how you took it out? Also, did you have to drain alot of coolant to do this?

[IndyTom]

Originally Posted by berry03

Sweet! But now the next part. How do you take it out Looks like the green clip that holds it in you move it to one side, was that how you took it out? Also, did you have to drain alot of coolant to do this?

Replacing it was a 2 minute job and I didn't spill a drop of coolant. The trick is to let the car sit and cool down overnight which reduced the coolant pressure. You may want to put some paper towels underneath just in case.
Unhook Electrical connector, Pull out the clip securing the Thermal Switch and then pull the switch straight up and out.
Remove the old flattened Rubber O Ring and replace it with a New One. Then push the new Thermal Switch back in, Make sure it is seated properly and then replace the clip and hook the electrical connector back up. It will take you less time than I just spent typing it.

I can't find just the O-Ring at ECS Tuning. I know they have it since I ordered it from them but their search engine isn't up to the challenge I guess.
Here is another site that has the O-Rings for about 22 cents. http://www.koperformance.com/part-number/N90316802/FEBI
The Part Number for the O-Ring is N90316802 Perhaps your dealer may have one and if you are lucky they will only charge you 3 or 4 bucks for a 22 cent O-Ring.
Or you can chat online with ECS and they will look the part up for you and send it along with the switch.

[berry03]

Thanks Tom, and the rest of you guys. Going to call the dealers and get the new parts this morning, and change them out. We'll let ya know how things go afterwards.

[IndyTom]

Originally Posted by berry03

Thanks Tom, and the rest of you guys. Going to call the dealers and get the new parts this morning, and change them out. We'll let ya know how things go afterwards.

Make sure you give the dealer the OEM Part number or they may try and give you the wrong part. Happened to me here. They gave me a very similar part which looked the same but it wasn't. It was "White" in color and I thought perhaps they just changed color over the years and installed it. It fit just fine but it didn't work. I took it back and ordered it from ECS tuning which delivered in 2 days time. Also the dealer will take over double of what you can order it for online and most of the time they don't even have those things in stock. Anyway, if you do go to the dealer make sure to give him the OEM Part Number: 357919369F
Make sure it is black in color with a green stripe on the bottom rim. Good Luck and let us know how it turned out and if it fixed your problem.

[berry03]

Ok, just came back from a little drive, about 5-7mins, with the a/c blasting, and guess what. Nothing The big fan still didn't come on. Only thing I can think of is I didn't get the engine hot enough, or the coolant hot enough for it to kick on. Any ideas?

[Design]

with the engine off and cool see if you can turn the larger fan freely by hand. Mine seized up. If it spins compare it to how much it takes to spin the small one. Single replacement fans but usually not locally.

JB

[Oh Randi]

Originally Posted by Design

with the engine off and cool see if you can turn the larger fan freely by hand. Mine seized up. If it spins compare it to how much it takes to spin the small one. Single replacement fans but usually not locally.

JB

There is also a thread on here where someone's fan seized up and they took it out and cleaned the internals and that worked. I had to replace the big fan last summer. Not cheap. But definitely not $600.