1969 polara noisy engine fan

[polarnj]

Just got this car recently, the fan roars like a school bus. It's a 7 blade fan, presumably with a heavy duty clutch. Is it more the fan or the clutch that causes the noise?

The p.o. said that 383s need the hd clutch because they run hot (?), is it totally necessary or can I get by with the standard quieter one?

 

[Big_John]

Just got this car recently, the fan roars like a school bus. It's a 7 blade fan, presumably with a heavy duty clutch. Is it more the fan or the clutch that causes the noise?

The p.o. said that 383s need the hd clutch because they run hot (?), is it totally necessary or can I get by with the standard quieter one?

The HD clutch is not any noisier.

If yours is making a lot of noise, there's two things... First... Are you sure there's a clutch? Some guys will bolt the fan directly and eliminate the clutch. Second, when the car is off, can you turn the fan easily? If you can't the clutch must be bad... Although I've never seen one fail where it won't spin, but that's just my experience.

 

[57fury440]

I never heard that 383 motors tend to run hot. Check you fan clutch, because it may not be working properly.

 

[CBODY67]

If any Chrysler w/factory a/c runs hot in that part of the country, it probably needs a radiator re-core and the block water passages cleaned out. To say that in AZ, is a different situation.

What does the instrument panel gauge indicate?

Enjoy!
CBODY67

 

[polarnj]

The HD clutch is not any noisier.

If yours is making a lot of noise, there's two things... First... Are you sure there's a clutch? Some guys will bolt the fan directly and eliminate the clutch. Second, when the car is off, can you turn the fan easily? If you can't the clutch must be bad... Although I've never seen one fail where it won't spin, but that's just my experience.

There is def. a clutch there, it's pretty big. I'll check to see if I can spin the fan, what am I looking for? Should it spin easily?

 

[Ross Wooldridge]

I just installed a new clutch on my 440's fan, and it too roars like a school bus. I hate it, but the car definitely runs cooler than it used to.

Not sure what to do.

 

[polarnj]

Maybe it's just me, but I noticed that the cars at the show with no clutch at all don't seem to have that noisy a fan, at least not as much as mine. Maybe they are not 7-bladers

 

[CBODY67]

In many respects, the factory 7-blade fan was not that noisy to me. When started, it would make some "fan" sounds, but in a few seconds, quiet down to nothing. That was the way the OEM and later DANA/Spicer replacements did, too.

Not sure about the HD versions, but when I was seeking to not spend money (I didn't want to spend at the time) on a new fan clutch, I discovered that I could dimple the outer "oil reservoirs" on the front (with a blunt Phillips-head screwdriver) to increase the internal pressure and more "lock-up" the innards so the fan took longer to uncouple. I could hear it up to about 30mph in low gear, then the air coming through the radiator would overpower it and it would quieten down.

At the Chevy dealer I worked at, in the summer, sometimes we'd have customers come in and complain that their 454 tow vehicle's transmission was downshifting too much. Turns out they were hearing the clutch fan cut in and out.

So, drive the car and see if it doesn't quieten down after you get to about 35mph or so.

One time I didn't want to buy a new fan clutch (see above) and put a Flex-A-Lite stainless steel flex fan on the '66 Newport Town Sedan. It WAS loud. Sounded like a jet getting ready to take off at 60mph on the highway! Tried spacing it in and out of the shroud, no help. I could take the air cleaner off and not have to worry about burning my hands after an hour drive on the Interstate at 70mph in TX July heat. It was moving THAT much air, but not increase in mpg from it pulling the car down the road! Ended up taking it back for credit and reluctantly going back to an OEM Dana fan clutch.

Just my observations and experiences,
CBODY67

 

[polarnj]

Well when I test drove the car it was roaring all the way onto the highway, so I don't think it ever really quiets down much. I'm getting the insurance taken care of so it should be on the road by next week

 

[Justin Plant]

When you replace a clutch you will notice fan noise, but generally at low speed or idle. I should pretty much free wheel at highway speeds. The fan can't pull any more air than you're already forcing through the radiator at 60 mph.

 

[mr gtx]

I tried one and it did roar it will turn faster than a standard one. I took it off. it will cool better at idle and low speeds but will block air flow at higher speeds and will cost horsepower. to run one they say you need a different pitch fan.

 

[Just Carbs]

There is about a 10-degree temperature difference between the standard thermal and the heavy-duty thermal fan clutch lock and release temp. They work at about 175 radiator air flow temps, plus or minus.
I haven't had any fan roar with any of my old Mopar cars. They have all been quiet and cooled well. So, I'm not knowledgeable on them.

However, I do have a 93 V/8 Dakota that I abuse when towing in extreme heat.
The Dakota was built with what Dodge called a Super Cooling Package, or something like that. It has a very aggressive fan pitch and a thermal clutch that locks/releases at a low 170 degrees radiator air flow temp. At 3200 rpm it roars like an airplane propeller and cost a LOT of hp. It makes a BIG difference in cooling capacity at 3200 rpm (start of max torque) climbing hills at 40 mph in second gear.
The problem is that it will engage on a 95-degree day whether it's needed or not. Very annoying in low demand non towing city/suburban/interstate driving.

My 97 Dodge van that I don't tow with has a similar cooling package. It had the same behavior. I replaced the heavy-duty clutch with a standard duty clutch that locks/releases at 10 degrees hotter, and it is very quiet now.

The theory that the air moves through the radiator faster at 60 mph than the fan can pull might be incorrect, depending on the rear gear. The Dakota (3.91 rear) fan will engage on a 95-degree day at 60 mph and then quickly disengage about 15/30 seconds later as a result of the increased air flow through the radiator from the fan engagement.

I question if we need the thermal clutch for non-towing cars. I think the regular centrifugal non thermal clutch that pulls all the time at idle and then releases at a given rpm might be a better choice. They work better for a/c performance in slow traffic.

 

[CBODY67]

When fan clutches first came out, they were the centrifugal type, which cut-out above a certain engine rpm level. Identified by no thermostatic spring to regulate internal fluid pressure.

When the thermostatic versions came out in the 1963 era, they were considered "upscale" as they could better modulate fan function to the demands of the vehicle cooling system vs. engine rpm. By that time, the earlier centrifugal versions were relegated to the "bargain basement" ares for people who couldn't afford the little bit extra price of the thermostatic units at replacement time.

There ARE some ways to tweak the OEM clutch's performance, seems to me. If you want a little bit quicker heat response, then carefully disengage the end of the thermostatic coil and put it on the tighter side of the retained area, for a bit more tightness. When I did this, it did not seem to make much difference on our Chrysler, but I knew it should, if it needed it.

On our '66 Newport 383 factory a/c car, if the coolant was at the spec level and the radiator (26" in this case) was not gunked-up with deposits, there was NO reason for the "HOT" light to ever illuminate. Those cooling systems just worked well by design. No trailer hitches or towing involved, just driving down the streets/highways normally at up to 90mph (where safe to do so).

Our service station guy (whose favorite cars were '65 Fury III 4-dr sedans, as he had a son and daughter) told me onetime that if a pressure-related leak might occur, to carefully release the pressure and then let the radiator cap be at the last safety catch to is would stay installed, but not allow any pressure to build up, and no coolant would be lost. From either the pressure-related leak or from the filler neck. This was on the old round-top radiator tanks. When I tried it on a square-top 1980s version, didn't work so well. I figured he knew what he was talking about as he'd driven/been around these cars much more than I had been, at that time. Proceed at your own risk. FWIW

Enjoy!
CBODY67

 

[Just Carbs]

I've seen some Toyota fan clutches with adjustable spring positions.