troubleshooting radiator fan

[heygibb]

I got my car back today after having a fuel pump replaced. It seems to run normally again, although I couldn't really cruise around due to the inner radiator fan not functioning properly. W/ the engine off, rotating the fan results in a rubbing between the fan and the housing for some reason. I never noticed it before, but there is an electrical burning smell down in that area when I put my nose close to it. The wires aren't chafed or melted, that I can see, but I'll look closer tomorrow. Any history of failure on those wires feeding that fan?

Has anyone ever had to replace that fan before? Is it an aftermarket part? Sources? I apologize for asking but I've had a long day and hadn't had time to search it out yet. I'm thinking the u pull it yard.

I really don't know why the parts are rubbing, but they are. The shaft on the fan feels solid to me, so I don't think it's a bearing issue. I really don't know why the electrical smell is there.

Edited April 5, 2011 by heygibb (see edit history)

[D-a-n-i-e-l]

I could not find one that fit so I found a motor from an other vehicle that matched. Not a recommended methode but if need be they are out there.

[heygibb]

The thing is, I don't think it's the motor but the fan and housing. Since it's all plastic, it's almost like one of the two warped out of shape and interferes w/ the other. Tomorrow I'll try to determine if it's the fan or the shroud that is warped and go from there.

That little bit of resistance on each revolution could put stress on the motor and cause it to overheat, thus the electrical smell. I'm just not sure yet.

I might try to grab the whole shebang from the Riviera I've been snatching parts from.

[Barney Eaton]

If it is rubbing and you need to replace it anyway, why not remove it and evaluate the problem out where you can see it.

On the bench you could you might be able to fix the rub and test the unit.

A Riviera part from the vintage should bolt in place.

[heygibb]

If it is rubbing and you need to replace it anyway, why not remove it and evaluate the problem out where you can see it.

On the bench you could you might be able to fix the rub and test the unit.

A Riviera part from the vintage should bolt in place.

I will. Going into it, I am expecting distortion due to age and heat. The fire potential from shorted wiring is of equal import, too.

I'll post what I find out.

[heygibb]

Just following up...

I removed the inner fan shroud and fan. It's very simple to do. Once I could take a good look at it, I found the shroud was 1/8" out of center. That left me w/ a 1/4"+ clearance between the fan and shroud on one side and a 1/16" or so clearance on the opposite side. W/out the tension from the mounting bolts, the fan cleared the shroud on the bench. I saw no cracks in the frame, so maybe fatigue allowed for the fan motor to settle a little off center. There was no play in the fan shaft and it turned freely. I ended up remounting it, for the time being.

I traced the electrical burn smell to the box of relays on the right side of the engine compartment. I pulled each one out, smelled for the burnt odor. The only odor I found was coming from the platform the relays were plugged into.

I don't know how to check a relay, so I put it all back together. I'll ride around w/ a fire extinguisher at the ready in case I experience a fire.

According to the label under the relay cover, those relays control both inner and outer fans, among other things. Perhaps the friction between the fan and housing was causing a relay to overheat. Is that possible?

Thanks

Tim

[2seater]

The fans do have a small drag/free/drag type of feel to them. I imagine it is when the segments inside the motor line up with the magnetized portion. The two fans on a '90 operate in series for low speed and parallel for high speed and the relays are what do the switching between the two modes. The relays are common five terminal 20/30 amp and could be switched with almost any others to test operation. Does the fan in question operate on straight 12v?

[Barney Eaton]

There is a diagram on the side of the relay that shows the schematic.

With a power source (battery charger) a jumper or two and a 12V lamp, you can test the relay.

[heygibb]

The fans do have a small drag/free/drag type of feel to them. I imagine it is when the segments inside the motor line up with the magnetized portion. The two fans on a '90 operate in series for low speed and parallel for high speed and the relays are what do the switching between the two modes. The relays are common five terminal 20/30 amp and could be switched with almost any others to test operation. Does the fan in question operate on straight 12v?

The drag on mine was from actual rubbing between the fan edge (actually a ring around the fan itself) and the housing.

I noticed the identifying info re the relays on the enclosure. I might grab the ones on the Riv tomorrow as backups. I've never replaced them and have no idea of their lifespan.

I did not straight wire the fan to see if it worked. I'll check it out after I run the car a while tomorrow.

Thanks for your comments.

[heygibb]

There is a diagram on the side of the relay that shows the schematic.

With a power source (battery charger) a jumper or two and a 12V lamp, you can test the relay.

I'll check into that. Thanks.

[heygibb]

...just a follow-up to my fan issue.

I grabbed the fan from the '93 Riviera at the u-pull-it, along with it's relays. I did not electronically check my relays, but found two that had a white material oozing out from around the spade plug and smelled "burnt". I replaced all of my relays w/ those from the Riv. They were at least 3 years newer and looked it. Prior to changing them out, my fan did not operate upon start up of the engine. After the change out, it ran from the get go after the engine cranked.

The Reatta fan, as stated earlier, has a housing surrounding the fan itself and is mounted through the housing. Through age and fatigue, my fan settled into an "off center" position and started rubbing the shroud. The Riv's fan had no housing at all. It was a free standing fan that had a four position mounting system. The lower legs were plastic tabs/feet that are inserted into rubber bushing/mounts. The upper two legs mount w/ bolts into the radiator shroud. I liked it better since it removed any possibility of rubbing.

I forgot to take a pic of the Riv prior to mounting but it's viewable in the following pics, already in place. There, also, is a pic of the relay platform and the original fan.