Car Truck SUV Engine Cooling What is a Cooling Fan Clutch

In this video, I'm going to talk to you about cooling fan clutches.

Hey, friends, it's Len here from 1A Auto. First of all, I wanted to let you know that not all vehicles are going to have a fan clutch that looks like this. I just want to let you know that right off the bat. Some vehicles are going to have a fan that's actually mounted directly to the water pump. That's going to be on much older vehicles, such as maybe one of those antiques that you might have laying around in your garage. Or on some newer vehicles, especially engines that are transverse or if they go side to side, they're going to have an electronic fan, which we can talk about a little bit later. With that said, something to think about is that this video is going to be specifically about fan clutches, okay? It looks a lot like this. There's going to be two different types of fan clutches that you can get. You can get thermal or you can get non-thermal. The thermal ones are going to be much more efficient overall. They have this little spring located up front, and what happens is when the air that's located in front of this, between the radiator and the fan itself gets hot enough to approximately 170 degrees, it's going to expand the spring right here, which internally is going to open up a valve and let silicone move freely inside of this fan clutch itself. You're going to be able to see it because it's located inside. As that valve opens up, centrifugal force from the engine spinning, turning that serpentine belt, also making this spin because the water pump's spinning, it's going to shoot that fluid facing out, which, of course, is going to activate it at that point, and that's going to make your fan turn around, and around, and around. And the fan is going to draw air through your radiator and cool everything down.

Now, the thermal type fan clutch is going to be mostly inactive. What you're going to notice is that, yeah, it is going to spin a little bit, but it's not going to be under very much pressure, especially when the engine's cold. The reason for that is because the engine needs to get up to operating temperature. Like I said before, once the engine reaches approximately 170 degrees Fahrenheit, this is going to want to actuate. Once it actuates, it's going to keep going, and it's going to try to maintain a specific operating temperature for your vehicle, which would be approximately 195 to 220 degrees Fahrenheit. At that point, if it starts reaching above, this is going to actuate even more and it's going to keep that fan spinning, trying to draw air through the radiator and cool down the engine/cooling system, which, of course, is going to be super important for in case you're sitting in traffic. Maybe you drove out to the beach and you're sitting on the boardwalk, and for some reason, traffic just isn't moving. Your vehicle is sitting still, there's no breeze flowing through that radiator, so you need something to draw the air through to cool everything down.

Something that's important to remember about your fan clutch is, of course, the fan's attached to it. The fan is going to be drawing air through that radiator, and, of course, it's going to cool down your engine/cooling system. Something else to think about is that your transmission also needs to be cooled as well. Usually, inside of your radiator, you're going to have a separate cooling system for the transmission that's going to run through there as well, and it needs to be cooled down. If you don't have the system that runs to the radiator, you're probably going to have an external cooler, which will be located in front of the radiator. Once again, if air isn't flowing through that cooler, then you're not going to have a good running temperature, and, of course, you could potentially cause damage to either your engine or your transmission.

Now, a non-thermal clutch is going to look approximately the same as this one, it's just not going to have a spring right there. Internally, it's going to be different too, but you can't see it, so why really talk about it? With that said, the non-thermal clutch doesn't need to know what the temperature is of the air around it. So, what it's actually going to do is it's going to spin approximately 30% to 60% of the speed of the pulley that it's attached to.

So, now, like I said, not all vehicles are going to have a fan clutch that looks like this. Some vehicles, especially front-wheel-drive vehicles, have a transverse engine, which means that it goes from side to side. In which case, as you look at the front where the radiator's going to be, you're going to notice that there's no pulleys. All the pulleys are going to be located on the side of the engine. With all the pulleys located on the side of the engine, what you're going to notice is there really isn't very much room to try to fit a fan and a clutch down inside there. It just wouldn't be functional. And secondly, really how much air is it going to draw through the radiator, which is located in the front? It needs to be located in the front. These cars would have a fan located up front right here, which is going to be located between the radiator and the engine itself. If you have an electronic fan that looks like this, that's going to actually be powered up by the car's computer. Now, where it is actually located is right underneath all this stuff. So, we'll get it out of the way so you have a clear view.

So, now, looking at this engine, you can tell that it's a longitudinal engine, which basically means that the engine runs from front to back, not side to side, like the transverse engine. With that said, you're going to find the belts and all the pulleys located right up in the front near the radiator. The fan clutch is going to be located attached to the water pump. You can tell what's the water pump because, of course, it's going to have coolant hoses going to it.

So, now, there's a couple of ways that we can check our fan clutch. With the engine off and cool, you can carefully reach behind and go ahead and grab onto that fan and see if you can wiggle it around. If for some reason your fan moves like this one does, this is obviously no good. If it moves just a teeny bit, it's probably not very bad because there is just a little clutch and a bearing and everything inside there. So, you're bound to get a little bit of movement, but this is excessive. Something else that you might notice is maybe you grab onto the fan and you go to give it a little spin, and for some reason it just has a lot of drag and it doesn't want to spin. And as you try to spin it, what you're probably going to notice is the water pump even tries to spin a little bit dragging against the belt. The reason for that is because the bearing inside is seized up. Maybe the grease came out and moisture made its way in.

So, now, when you're checking it and you're noticing movement like this, you want to double-check to make sure right along the backside of where the clutch is, it's actually the clutch that's no good and not the water pump pulley bearing itself. So, if I'm moving this, I can see that just the fan's moving and the pulley isn't. But if I was moving this and the fan and the pulley was moving, that would tell me that it's actually the water pump that's no good.

Now, some of the symptoms that you're probably gonna notice aside from the physical ones might be something as simple as in the wintertime, you start up your vehicle and you want it to get up to running temperature. For some reason, the vehicle just takes a very long time to warm up and you wonder why. The reason why is because maybe internally on the clutch, it's frozen. If that happens as the crank's spinning around, it's spinning that serpentine belt, which is, in turn, spinning the water pump and, of course, the fan clutch pulley. If the fan clutch pulley is frozen, it's going to keep spinning that fan with the speed of the engine and, of course, blowing cold air on the engine and it's going to take forever to warm up. Something else that you might notice if that is the instance is you're probably going to sound like a helicopter is taking off every time you rev your engine [vocalization]. Because as the engine revs up, it's spinning faster. That spins faster, the serpentine belt spin faster, the water pumps spin faster, and, of course, so does the fan. Every time you rev up the engine, the fan goes faster as well creating more air. Something else that you might notice is maybe for some reason, the engine overheats, or even your transmission overheats. You start to wonder why, I changed out the coolant. I did my radiator. I did my thermostat. I don't know what's going on. Something that could go wrong is that fan clutch like I said. If the fan clutch is no good and it has a lot of movement, more than likely it's not going to activate the way that it should, so it's not going to know when it's time to cool the engine. If the fan clutch isn't activating, spinning the fan and it's not cooling the engine, of course, your engine is going to overheat, especially if you're sitting still in something such as traffic.

Now, to replace the fan clutch, once you've diagnosed that it's actually no good, what you would have to do is, of course, get everything out of the way so you have a nice clear view. Leave the serpentine belt on, and then you're going to use a tool that looks a lot like this right here, put it right over the nut side right there, and then use an air chisel if you have access to one, and then break this free in a counter-clockwise manner. Once it's broke free, you can continue spinning it off because it just unscrews from the actual water pump itself. Take that off completely, it's going to come with the fan. Unbolt the fan, remove that, put the fan back on the new clutch here, go ahead and turn this clockwise until it bottoms out, and then just give it a quick love tap just to kind of bottom it out, but you don't need to really hammer on it at that point. Put it all back together, recheck everything, take it for a road test.

If for some reason the symptom that you're noticing with your vehicle was an overheating problem, I wouldn't contribute it to only the fan clutch and just say that that needs to be replaced. There are other things that you should think about, condition of your coolant, level of your coolant, your water pump function, make sure your thermostat's opening properly, and, of course, make sure that you clean out that radiator because if the radiator's full of gunk or debris or anything like that, it's going to cause an issue with overheating.

So, I know what you're asking, can I delay fixing this? I would go with no. You want to fix it ASAP. The reason for that is because if you don't fix it and you're engine is not running at proper operating temperature, you're going to get poor fuel economy, and even worse, you could cause detrimental damage to your engine and even possibly your transmission.

Okay, friends, so we tried to make you an informational video about fan clutches. Hopefully you learned a little something. If you did and you want to talk about it, leave it in the comment section below because I'd love to hear from you. While you're at it, if you like the video, why don't you go ahead and smash on that like button for me, it would mean the world. Go ahead and subscribe and ring the bell, that way there you can be kept up with all of our latest content. Thanks.

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