I don't disagree with either of these assessments, but I'd like to go back to the beginning and ask 72455 a basic question...

Nowhere have you stated WHY you went and spun the fan in the first place. People don't routinely spin their engine's fan when they check the oil or whatever. What made you decide to test the fan in the first place?

Was the car overheating? You mention later that the temperature creeps up a bit in traffic, but this is normal, and the increased temperatures you mention are not much and not an indication of a problem.

Was the fan making excessive noise? Sometimes this is difficult to detect over the normal roar of the engine, but you'd notice it if you're used to the sounds your engine makes, which I'm guessing you are. That was the symptom I mentioned earlier that had me changing the clutch in my '75 Delta 88. i didn't mess around testing things when I heard the noise. I went right out and bought a new fan clutch, installed it, problem solved. If yours is making noise, just replace it.

If the engine wasn't overheating and you didn't hear any noises, what other reason would you have to think that it's time to go and spin the fan? Perhaps you're just one of those people who can't stand the thought that there isn't SOMETHING on their car they can work on. I know the feeling! Lie down until the feeling passes.

 

The only reason I'm concerned is because of the slight increase in temperature when I'm in stoplight traffic. It never used to get above 200 no matter what the ambient temperature was. Now that it's climbing a little higher, I was trying to figure out why. I know my coolant system is good because under normal driving conditions, it stays right around 200. This led me to the fan clutch. You already know my troubleshooting steps, so I won't regurgitate that. To answer your other questions, no overheating, no excessive noise, and no grating or rough turning when I spin the fan by hand. Just the abnormal tight spin when cold and free spin when hot. Why am I concerned about the slight increase? Well, as I have said, when it gets hotter during the summer, will my temp increase even more? If so, I don't want to wait until then to find out. I'd rather get ahead of it now than to wait.

 

As I said, the slight increase in temperature at idle is nothing. But if you have any doubts, and it will make you sleep better at night, just replace it.

Temperatures ALWAYS rise a bit when sitting in traffic after having been traveling at highway speeds, even with perfectly-functioning fan clutches. The fan clutch kicks in in such situations to keep the temperature from getting too high, but it doesn't necessarily mean that it will bring the temperature back down to what it was when you were driving at highway speeds. That's not necessary and not the goal. Preventing overheating is all that is necessary. 210 to 220 is not even close to overheating.

As I said in a different thread many moons ago, I owned a '75 Chevy Nova with a 250-six cylinder engine from 1976 to 1986. One of the first things I did, in violation of the moral of the story in The Engine Temperature Carol, was install a temperature gauge. Just for the fun of it. I was 19 years old, had just gotten the car, and I had already replaced the AM radio with an AM/FM system. I needed something else to do. The car had no overheating issues, and I had no idea what the "correct"operating temperature was. For the entire time I owned the car, ten years, the temperature gauge stayed in the 215 to 220 range. I thought nothing of it, and I never had an overheating problem.

Cold engines are NOT a goal. From a thermodynamics standpoint, the higher the temperature an engine operates at, the more complete is the combustion and the more efficient it is. Engines that operate too cool have incomplete combustion and carbon build-up problems. That's why engines have thermostats. To get the engine warmed up as quickly as possible, not to keep the temperature from getting too high. Once the thermostat opens, it's out of the equation, and it is up to the rest of the cooling system to keep the engine from overheating. If keeping the engine as cool as possible were the goal, a thermostat wouldn't be needed and would actually be counterproductive.

 

Got it. So no worries about the summer heat?

 

I would worry about this when summer actually gets here. I would guess you won't have a problem. But if you do, put in a new clutch.

 

It's easy to worry too much. I've been continually guilty of that.
I would say that 180 is kind of ideal, but 200 is just fine. New cars tend to run between 200 and 215. Anything up to 220 really isn't a concern, but over 230 starts to get interesting and over 240 is concerning. 250 is my Shut Down Now threshold.
Below 180 will actually cause problems with contaminants not getting boiled out of the oil.

 

So I'm going to wait and see what happens once it gets hotter outside, but in the meantime I've sourced an OEM unit.

 

With all you've just stated, have you ever considered the "Gauge" is faulty? Did you troubleshoot the gauge itself or you going to assume the gauge is and always has been in perfect condition and always displays the exact correct temperature?

 

I dunno if it displays the exact correct temp, but I do notice an increase in temp when I'm sitting in stoplight traffic. I guess I could verify with my temp gun.

 

https://shop.advanceautoparts.com/p/...source=certona

 

Sometimes OEM is good! Sometimes time isn't our friend. I wouldn't trust that an original fan clutch is still good out-of-the-box any more than a new aftermarket. There's fluid and seals and mechanical bits in there. I never had a problem with aftermarket clutches - standard or HD. Just treat them like a maintenance item that might need to be changed every few years.

 

During the 1980s the common wisdom regarding viscous fan clutch units was to never store them in a horizontal position. In fact replacement clutch units were supplied in boxes with 45° angle cardboard inserts so that the clutch unit would never be horizontal, regardless of the position of the box.

 

In my experience, during the 80s, the fan clutches for Olds V8s came in boxes that didn't have any wedge shape anything in the boxes. I've bought a few in my day. They came in a box with a part number on it and maybe a sheet of oil paper to keep the shaft from rusting.

 

Is this your box?

 

????

 

So further diagnosis revealed that I in fact to have some wobble where the fan attaches to the clutch (no water pump wobble). Good thing I've got another clutch on the way.

 

I got my replacement fan clutch today. Part #4950788. Seems it's heavy duty

 

So I replaced the fan clutch today, and the temp stays a steady 200-205 even at idle and in gear. I'm calling it good 👍. Thanks to everyone for the advice.

 

Isn't that the level it rose to which caused your concern in the first place, leading to this entire exercise?

And BTW, how many times can you rotate the fan now, hot vs. cold?

 

It actually would climb to about 220 in stoplight traffic before. Thats with an ambient temp of around 75 deg. Today was 85 deg, and it stayed right around 200-205, so I think it made a difference. As far as how many spins, well, it hasn't completely cooled down yet, but when give it a flick, it's rotates maybe 3/4 of a turn. I'll check it again once it's completely cooled down. I'll have to check hot spins when I take it out again...I forgot to do that when I got back today.

 

Does it roar, and the old one didn't?

 

that seems high to me - Like I noted earlier, I'm here in FL and only average 180-ish under most running conditions unless stuck in idle summer traffic for more than 10 minutes, at which point it MIGHT see 200 but otherwise only hover in 190-195 range until I start moving again.

For me, I'd be nervous averaging 200+.

 

I couldn't really tell the difference.

 

Read #43 above.

 

The following from Fan Clutch Restoration, located at: http://www.kirkconnellcorvettes.com/home.html

Q: How many times should my fan rotate after shutting off the engine from an idle?

A: Typically your fan should make one-half revolution or less and stop, after turning the motor off.

 

Didn't click on link, but this statement reads a little ambiguously -- do they mean one half-revolution upon shutoff or one half-revolution by hand with the engine still hot but already off?

 

That would be by the car spinning it. By hand, when warm, the fan should spin about one blade width, i.e., "some" but not much at all. It should be almost locked up.

When cold, by hand, the fan should spin 1/2 rev. It should be almost free wheeling.

Complete freewheeling and completely locked up are failure modes.

 

Cool, I thought I had talked about my 2 new clutch fans I put on my Cutlass and Vista, but looking back , I guess I didn't... Well I hope that takes care of it, I'll bet it does- did for me, but Oh what a Roar!!

 

Funny, my experience is almost the opposite.
Cold, barely turns because the fluid is thick. Hot, spins easily because the fluid is thin. Hot enough to trip the thermo switch, it'll feel almost locked up.

 

UPDATE: It seems I may have spoke too soon. Took it to work yesterday and it stayed around 200 on the way there. Coming home it initially climbed to 200, but about 1/2 way home it crept up to about 220 and stayed there. Ambient temp of around 90 deg, and I also noticed my reservoir level was slightly higher than usual. Maybe I need a splash of coolant?🤔

 

If your coolant is pushing out of the radiator into your overflow / recovery tank when hot, adding more coolant won't help since your radiator is already full of coolant (which is why it is expanding out into the overflow / recovery tank). Just make sure that when the engine is cooled-down that the coolant gets pulled back into the radiator from the overflow / recovery tank. If the coolant isn't returning to the radiator when cool, you may have an air leak between the radiator and the overflow / recovery tank allowing air to get sucked back into the radiator instead of coolant.

Can you hear the fan roar as a result of the clutch engaging when it is hot at 220F? I would think that it should.

 

I really don't know what to listen for.🤔