Roaring clutch fan when cold?

[Mkt1]

Hey guys quick question. I have a 2007 Lincoln Navigator with 160k miles. Vehicle would start overheating when idling then AC would blow warm. I bought a new clutch fan from Amazon. The manufacture was GMB for $127. The overheating stopped but the issue is I hear that loud roar every time It takes off in first gear then goes away. It happens wether the engine is cold or warmed up. Is this normal or should I replace it with a more expensive one or oem. I don't remember it doing that before, but the clutch fan has been acting up for a while.

 

[Barjrob1972]

Nope. That's normal.

 

[Habbibie]

Nope. That's normal.

I don't recal that as being normal, what you're referring to is the loud roar upon starting the engine I think but while in gear it shouldn't act that way, I'm not sure what is the exact cause of that but maybe someone who has experienced this can chime in.

 

[ExplorerTom]

I replaced what I can only imagine was the factory fan clutch at 16 years and 190,000 miles. I didn't have any overheating concerns. The old clutch probably worked but I never heard it. I replaced it with a severe duty clutch. Now the clutch is engaged at the beginning of every cold start. It goes away once I get above about 30 mph. And then if it heats up over 200, the clutch will be heard again at speeds under 30 mph.

I read somewhere that the average fan clutch loses 100 RPM per year. If that's true, and was down 1600 RPM.

 

[Barjrob1972]

I'm not going to type up an explanation of how a viscous clutch works as there is plenty of information out there already but what is being described is normal operation, particularly when they are new. It should be stiff to turn by hand and it should sound, usually but not necessarily every time, like a jet engine when you first increase the RPM's of the engine. They have worked this way forever. They are at a 1:1 ratio until the fluid settles and then it will decouple. If the bi-metal spring gets heated, it will open the fluid reservoir and re-couple the fan to the clutch causing the fan to roar again. Although it can be parasitic to HP and TQ when coupled, it's probably the best engine cooling fan out there pulling upwards to 10,000 CFM of air. It sounds like the OP installed a heavy duty fan clutch particularly giving the price that was paid.

 

[Big Brian]

another quick test is after the engine is completely warmed up, have a helper shut off the motor as you watch the fan. It should stop with the engine, if it continues to turn then its wearing out

 

[Mkt1]

Barjrob you explain it exactly right. We bought the vehicle brand new and I don't ever recall ever being that loud. Wondering being an aftermarket part would it be different from oem. Hopefully it does quite it down over time. I did recheck the part# and didn't say anything about being a heavy duty clutch fan. If it was me I would leave it alone but it's for the wife so I'm stuck lol

 

[stamp11127]

Well consider where you live and the summer temps. You have a fan clutch that "tells" you it is working at every engine start. Tell her to worry when she no longer hears it....

 

[Barjrob1972]

Barjrob you explain it exactly right. We bought the vehicle brand new and I don't ever recall ever being that loud. Wondering being an aftermarket part would it be different from oem. Hopefully it does quite it down over time. I did recheck the part# and didn't say anything about being a heavy duty clutch fan. If it was me I would leave it alone but it's for the wife so I'm stuck lol

So, I looked up what you bought based on your post and what I'm describing is an old school mechanical fan clutch which, from description only, is working as it should or at least as all mechanical fan clutches I've ever had dealings with have operated. It would seem yours is an electronic viscous clutch so maybe there is a sensor involved that's not working properly? At this point, I'm not sure. Regardless, I did find this video. It seems it works on a PWM and electronically controls the viscous fluid.

 

[lbv150]

I only buy OEM fan clutches or any other parts if I can including brake pads.