Cooling fan question..to replace or not..

My cooling fan on the drivers side had a blown fuse. It was noticed after the major service during final checkout that it was not working. So, I checked the fuse first thing and it was blown. It started working again after replacing the fuse. The car had never got hot on me prior to the service, but I also never paid attention to wether or not the fan was running because I never saw anything on the temp gauge that would make me think there was a problem. So, I do not know when it blew. The passenger side was and is working fine.

I did not look to see if the fan has ever been replaced or if it still has a stock one or the Spal 30102050 or 49 that people are using here. So, my question is this....

If you blew a fuse once, would you go ahead and replace the fan now or wait to see if it blows again and then replace it. Also, is there a chance it is fine and it won't blow the fuse again any time soon or do most people just see repeat blowing of the fuse? It had and still has a 30 amp fuse.

 

Well, during my troubleshooting of the slow down light issue I am having with the new exhaust, I discovered my drivers side fan is acting wierd even though the fuse is not blowing.

When I start the car (already warmed up), it will cycle on and off as you would expect trying to maintain temp then all the sudden it won't come back on and the temp starts climbing. The passenger fan comes on and saves the day and keeps it from actually overheating, but the drivers side will stay off. It does get warmer than it should at this point, so the drivers side definatly should be on. The wierd thing is, if I turn the key off, then right back on, the drivers side will start working again immediatly. The fuse is fine and even pulling the fuse and putting the fuse back on will not restart the drivers side fan once it stops coming on, cycling the key will however turn it back on.

When the drivers fan goes off and stays off, you can tap it with a mallet or push the blades etc and it will not restart. It does not seem like an intermittent issue in the fan. It seems as if the voltage is just not being sent to it anymore (I did not check voltages or anything yet). Also once it stops, even if you don't touch it, it will start working again with a cycle of the key.

Any ideas? Passenger side seems to work flawlessly and the drivers blows good when it is running. The fuse has not had a problem yet.

 

Mine makes a little noise when it starts up and when it goes off and is nearly stopped. Almost sounds like the blades are hitting a leaf or debris is kicking around, or it is barely touch something. But, when it is at speed it sounds fine and I don't see anything in there that would cause a noise. So, I am not sure what that little noise is at start up and slow down.

I am probobly going to go ahead and replace the drivers fan, but I don't think the fan is the problem with not coming on sometimes. I want to know what will cure that.

Is the thermoswitch directly controlling the fan, or is the switch connected to a relay?

I just need to know if I order a switch and a fan that is it, or if something else could be an issue.

 

I finally had time to look. As I suspected there is a relay. I did not think the switch would handle the fan load. It looks like the relay is Bosch 0 332 019 103 according to the WS manual.

It may be that my relay or the switch is bad, but I feel the best course of action is just to replace all 3 parts (fan, switch, and relay) and eliminate any possiblity of a component problem.

 

I have decided to just replace everything at once
Lower current fans
New relays
New thermoswitch and gasket
New overflow hoses (still researching this)

Everything is ordered except the hoses. Not sure what size and length to get or which ones for sure that can swell shut. Researching...I don't want stock junk though if I can find something better.

Once I have hardly any OEM parts left on this car, it is going to be a great car!

 

I don't consider it a shotgun since they are known trouble spots and have been stressed by the stock fans all these years. It's more of a PM. The relay contacts will have wear and possibly higher resistance from the arcing even if they have not failed yet due to the high current of the stock fans. It's just good insurance and cheep. If they were not so cheep ($7 each), I would swap them around and spend more time on it.

 

I got the 50 fans through fan-man.com for $117 each plus shipping
The thermoswitch and gasket from Ferrparts $29 for switch and a $1 something for gasket
The relays from Waytek, Part number 75301 $7.04 Each.

 

I put the new fans and thermoswitch in last night. I found the source of the issue I was seeing. It appears that the drivers side fan blade was warped. I believe if it would stop in a position that it was rubbing, this is when it would not come back on intermittently and also probobly why I had a blown fuse once. This is also why it was making a little noise when it slowed down.

I overkilled the repair and replaced the passenger side fan, the thermoswitch, and the relays as preventive maintenance and for piece of mind. Also, the new fans are supposed to draw less current so it will help the fuse block etc...

 

Couple pics of the new fans. They fit just like the originals. The only install difference is that the plug did not have the little holder on it like the factory one so you have to drill a small hole in the plastic and use a zip tie to secure it instead (or some other method of your choice).

On the passenger side, two of the mounting bolts have to be held on the back side. It took me a few minutes to find something I could reach the back side with to hold the bolt. I was able to get a really small 10mm wrench I have back there to hold them. Other than those two bolts the rest is just lock nuts holding them on. You will have to pop the plastic mounting tabs out of your old fans and put them in the new ones. It helps to hit them with a little wd-40 so they pop out easier. If you break them, you will have to find new ones.

Ignore the dirt I have not gotten to the cleaning phase of the undercarriage and engine bay yet. I have been working on this thing for 7 months and still getting it perfect. The good news is that I am almost to just some exterior cosmetic stuff to finish it.
Image Unavailable, Please Login
Image Unavailable, Please Login