Automotive Air Conditioning Information Forum

They seldom truly last beyond 3 years. The AC performance suffers waaaay before there are any overheating issues

hi
Thermal / viscous hub fans perform different for different makers .
The old test method is drive car for 20mins on a 75f above 20c day . The fan should have high drag or almost locked up when checked in the shop .

Replaced Toyota new vs old no difference .The fans are lazy .
Fords are very lazy fans , its mainly condenser size issue , this occurs on all the asian sourced vehicles alot. Been occurring since the 80`s .
Some condensers are that bad / small even adding a perf 12 inch e fan does not help .

A common trick is to separate fan hub halves and reoil with Toyota oil . 2 bottles typically works .

I had a 1972 Dodge Colt, 4-speed manual transmission (Mitsubishi, made in Japan)—bought new—that simply would never cool sufficiently. This car didn't even have a fan clutch—just a solid plastic, belt-driven fan. Couple that fact with a tiny condenser, and the reasons for its poor cooling performance were obvious. Other than that, it was a pretty nice little car for its time.

I managed to find an official test procedure from a Ford manual.

A laser photo-tachometer is needed & you have to measure the rpm’s at different engine temperatures & rpm ranges. There’s a minimum & maximum RPM specification.

I’ll try & upload it to this thread for anyone who needs to know how to test the fan accurately.

I’ve looked online and a decent quality tachometer will set me back $200-$300. I think it’ll be worthwhile seeing we get a few Fords in for AC.

IMHO, car manufacturers sometimes get carried away with their testing procedures and expensive tools. Unless you're curious, I don't think I would spend the time and money diagnosing a component that frequently wears out, that can be replaced in half an hour or less in many instances, and that can be purchased new at relatively low cost. If there's any doubt about the integrity of a viscous fan clutch, I would just replace it, especially if it's older than three years.

FAN CLUTCH TEST (MINIMUM SPEED REQUIREMENT)
1. Use twink to mark the fan pulley
2. Turn AC off
3. Start engine & run it @ 2000rpm for 5 minutes
4. Aim laser photo tachometer @ marked fan pulley. Increase engine rpm to 3500
5. With engine @ 3500rpm & using tachometer, record fan speed
6. If fan speed is less than specified rpm in less than 1 minute. Refer specifications
7. If fan speed was greater than specified, install a new fan clutch

FAN CLUTCH TEST (MAXIMUM SPEED REQUIREMENT)
1. Use twink to mark the fan pulley
2. Block air flow pathways (grille) to raise air temperature so fan can operate at maximum speed
3. Turn AC to 'MAX AC' setting
4. Start engine & run @ 2000rpm until operating temperature is reached
5. Run engine until fan pulley is at least 96C OR 205F
6. With engine @ 3500rpm & using tachometer aimed @ marked fan pulley, record fan speed
7. Fan speed must be greater than specified rpm in less than one minute. Refer specifications
8. If fan speed is less than specified, install new fan clutch

FAN CLUTCH SPECFICATIONS
1. Minimum speed requirement (2.2L & 3.2L) = 1000rpm
2. Maximum speed requirement (2.2L & 3.2L) = 2700rpm

JohnHere wrote: ↑Sat Dec 24, 2022 10:48 am IMHO, car manufacturers sometimes get carried away with their testing procedures and expensive tools. Unless you're curious, I don't think I would spend the time and money diagnosing a component that frequently wears out, that can be replaced in half an hour or less in many instances, and that can be purchased new at relatively low cost. If there's any doubt about the integrity of a viscous fan clutch, I would just replace it, especially if it's older than three years.

If both you & tbird say that 3 years is the standard life expectancy of the fan clutch then I'll keep that in mind when considering whether to replace the fan clutch.

I really went after an official Ford test procedure because the fan was initially passing what I know to be the 'standard tests' for a fan clutch. Turns out the fan had an intermittent problem & it has progressively deteriorated over time.

Also where I currently reside, only Genuine Fan clutch assemblies are available (fan blade & clutch) & they'll set you back $1200. The viscous fan couplings have been available from time to time but they aren't too good quality wise.

Autosaver wrote: ↑Sat Dec 24, 2022 10:06 pm Also where I currently reside, only Genuine Fan clutch assemblies are available (fan blade & clutch) & they'll set you back $1200. The viscous fan couplings have been available from time to time but they aren't too good quality wise.

Oh, my A price of $1,200 would give me pause as well. Check with Tim at ACKits.com, this site's sponsor, for the best parts and pricing.

JohnHere wrote: ↑Fri Dec 30, 2022 10:57 am

Autosaver wrote: ↑Sat Dec 24, 2022 10:06 pm Also where I currently reside, only Genuine Fan clutch assemblies are available (fan blade & clutch) & they'll set you back $1200. The viscous fan couplings have been available from time to time but they aren't too good quality wise.

Oh, my A price of $1,200 would give me pause as well. Check with Tim at ACKits.com, this site's sponsor, for the best parts and pricing.

I only suggest OE on fan clutches.