Man I would get rid of that clutch fan and get a direct drive fan never have to wonder if the clutch goes out
I agree with dmartin. I have the direct drive (non A/C car) and the fan is about half way into the shroud I added (which is what I always thought was the correct depth). Works perfectly.
I disagree with both you guys.
The clutch is there to allow a very aggressive fan to be used and to take advantage of it at lower speeds. At higher speeds, when the fan becomes redundant, the clutch allows the fan to slip and therefore not tax the engine.
It's basically good cooling with free horsepower... and if you look at the optional trailer towing, A/C, Performance Axle Package and the High Performance Package that was offered when our cars were new, you'll see that aggressive 7 blade clutch fan, a fan shroud and a 26" radiator. The A12 and Hemi cars came standard with the clutch fan, shroud and 26" rad. Again.. Superior cooling for harder usage.
It doesn't make any sense to start trying to bolt on aftermarket parts that might add a few HP at the higher RPM and then give away HP to run the fan because you are concerned about it not working.
The way our cars are used these days is way different than when they were new. I never waited in traffic in, let's say 1973, the way I do now. I didn't have to put up with crappy gas and I could run the ignition lead up where it belongs and still run nicely on the Hi-Test I bought for 35 cents a gallon at the corner. Cooling has become much more of an issue than it was when these cars were new.
That said... and here's where I get on my soap box... Most of the cooling issues I see are because the basics aren't followed. Example: My own car... The previous owner replaced the radiator with an aftermarket aluminum piece to "fix" the issue. Of course, it didn't... The car still ran hot at idle. I bought the car and my intention was to replace all the missing A/C bits and pieces. I run my cars hard and put them up wet... I expect them to perform correctly and not overheat and piss anti-freeze all over the place. I don't use any gas additives etc.
First order of business was to look at what the issues were and start fixing them one by one. The thermostat... Holy crap... a 192 degree 'stat. OE was 180 degrees.. I replaced that with a 160 degree because I knew they worked nicely in the summer months, but the 180 would have done the same. That took 15 degrees off the temp at idle. Next was a real radiator with a shroud.. and a 7 blade fan with a clutch. The first clutch was a cheap Auto Zone as that was the only thing I could get on short notice. (I was headed to Carlisle that weekend). The car ran much cooler and I was no longer worried about overheating while sitting in traffic. The "Severe Duty" clutch came a little later and now the temperature gauge doesn't raise at all. So.. Just basics... No junk electric fans... No aluminum radiators... and only two concessions to modern driving (the SD clutch and the 160 stat) and I can drive it anytime. Temp runs about 170-190 all the time, with the A/C blowing ice cold. Basic, no Mickey Mouse solution to a basic problem and quite frankly, most of it was cured by replacing parts that were removed in the name of "better cooling".
