I have a 64 Fleetwood and in the summertime with the a/c cranking when I would be in traffic or going slow it would always run warm....close to the 3/4 mark sometimes.

   I replaced the fan clutch with just about every brand they offered. all of them were just a standard duty clutch,(they make a severe duty one but my 5 blade fan didn't fit over the hub).

  when engaged it didn't seem like it was flowing enough air, aside from just solid mounting it to the water pump I was out of options.......then it got me thinking....I have a spare mint condition 6 blade 68 fan.....that just happens to fit perfect on the severe duty fan clutch....so I cleaned it up,and bolted it on.

I turned the heat up to 80 in my garage and let it run with the a/c on for about 45 mins (had exhaust hoses on it and wasn't staying in the garage haha) well at bout the half mark the fan clutch started to engage and was pulling some serious air. gave it a little rev and even heard the fan roar a bit....never heard that before....with the car running the garage was close to 90 now, inside the car was 62 and temp gauge less than half way the whole time. so im pretty pumped because I love my a/c.

  just thought id share incase anyone else was having the same issue.

Views: 516

Reply to This

Replies to This Discussion

and when its cool there is no fan roar and you can see it spin way slower.....doing some research I found that a standard duty clutch when engaged spins at about 35% a heavy duty 45% severe duty 60% and an extreme duty 80% so I should be flowing almost double the air now at idle 

Surprised to learn the different percentages of performance available with clutch fans
Interesting info

Greg, do you have the part numbers for the fan clutches.

I do russ. the severe duty four seasons one I used is 36704. the standard four seasons is 36954. the severe duty one will only work with the fan with the bigger opening, for some reason a deville is a different part number than a Fleetwood. I didn't know the devilles fan was any different.but the 5 blade from what I can see will only fit on the standard duty one.

I only recommend four seasons or delco. I tried imperial (advance auto) torqflo (auto zone) and murray (orileys) also tried a napa hayden one, they all failed in less than 2 weeks.....and they didn't engage til 221 degrees!!!!! used a heat gun and a laser thermometer to see when the spring would move. the 4 season ones engaged at 182. and the hotter it got the more it engaged. I know murray and imperial are "made" by hayden....but they all say made in china and an actual "hayden brand" is made in usa......but still didn't seem to engage very strong.....a small rpm change would release it.

doing some poking around almost all aftermarket fan clutches got terrible reviews.....for all the reasons I stated.....four seasons got very few issues. 90% of people just broke down and bought one from the dealer......but just to be funny I called a local Cadillac dealer and asked for a fan clutch for a 64 Fleetwood...and gave him my vin.....I was promptly laughed at.....so that route is not an option for us haha

I am so excited to see this thead. I have been struggling with engine temp. The engine temp was irratic and would go from cold to overheat in traffic or cruising. There was no rhyme or reason. Changed water pump, fan clutch from orielys, and put in a 160 thermostat. Yesterday I wired in oil pressure and temp gauges and I'm running between 190 and and 220 idling sometimes more, as last night at midnight.
My next next move was going to be radiator but I think I'm going to revisit the fan clutch. Thanks for the update!

Be sure your coolant is not old as it looses its ability to exchange heat correctly at the rad 

I have not temp issues - 64-429 

Always between the 1/4 ( 180 degrees ) and 1/2 ( 200 degrees ) mark on the gauge with 180 degree thermostat 

I have AC and do not have not have a clutch fan 

My fan is directly attached to the WP and it is a 5 blade stock fan 

You rad may be full of debris and need replacing 

I do still have the stock rad in my car since  the Cadillac is new 

I know the clutch of the clutch fans can go bad and need replacing sometimes 

Very glad you have solved your engine heat issue for your self 

Being —Cool —is a good thing for engine oil ( heat breaks down oil ) and  engine  health 


Hi Greg  I read your thread about your fan clutch, What diameter is that six blade fan?? I measured the fan housing opening on my Fleetwood and it measures 19 3/8  . The five blade is 18 1/4 dia That leaves over an inch of clearance for the fan  inside the shroud . I found a seven blade clutch fan off a 69 Eldo that fan is19" in diameter leaving only 3/8" of inch clearance. That's why i'm interested in the diameter of your fan blade. Thank you

If you should have a non - ac car the  addition of a fan shroud would help the  cooling a lot — only if it applies 

The middle mark on the temp gauge is  200 degrees and you do not want to be running the engine very much at temps much higher than that as it can be breaking down the engine oil being used - but not Syn motor oil that has higher temp tolerances 

When correct the gauge should be a little past the first mark on the gauge  — 180 degrees 

It will go up to the middle when idling in very hot weather and traffic but should return to just past the first mark for regular driving 

Do keep in mind that the Chinese temp gauges do not give correct readings and do not use plumbers tape when installing a new  temp gauge 
My 64 has AC and came stock with a 5 blade non- clutch fan and  now living in Fl the car is always running in 80 and 90 degree temps with no problem  at all but seldom in a lot of stop and go traffic 

I did replace a 5 blade fan on a 409 Chevy engine and went to a 7 blade fan that did drop my temp by 20 degrees so that could  help some 

It just might be that the rad needs replacing 

The Rad shop would judge the condition of the rad by how much it weighed as it gets heavy with a lot of debri in it clogging it up 


The engine temps will always be higher when idling for a long period under hot conditions   and should be judged when driving the car under normal conditions 

The engine temp will increase at idle going closer to the center mark on the gauge  but should return to normal when doing normal driving 

You really do not want to be running the engine at the center mark on the temp gauge as a rule 

 or any higher than that as a normal driving temp as that would be 200 - 220 degrees  

You want to be at 180 degrees for normal driving with our year Cadillacs 




  • Add Photos
  • View All


AC vacuum issues on '63 Series 62

Started by Terry Lange in Restoration Discussion 1 hour ago. 0 Replies

I recently had my AC compressor rebuilt and recharged with R12. 4 months later, it is still blowing 37 degree air, so I am happy.  This past Saturday I went to a car show which involved about 25…Continue

Master parts list manuals 1964 deville

Started by One piece at a time in 1963/64 Cadillac Specific Discussion. Last reply by One piece at a time yesterday. 5 Replies

Hi everyone just looking for some input as to which copy of the master parts list would be a better fit for meFor some reason there are 2 variations of them one being 1957-1964 and the other being…Continue

1963/64 Cadillac Chapter Website Membership Requirement Change

Started by Jason Edge in General Discussion. Last reply by Jason Edge on Friday. 4 Replies

The 63/64 Cadillac Website at…Continue

Blog Posts

'63 Eldorado trumpet horn + 2 standard horns restoration

Posted by Les Eastling on November 15, 2023 at 10:34am 1 Comment

My son, unbeknownst to me, had all three of the horns on our 1963 Eldorado completely restored. We had recently added the Eldorado trumpet horn to the two standard horns and the sound was not very good... we had heard good ones so we knew something was not right... but there was not much we could do to get better sound from the 3 horns. 

There is a restoration service called The Horn Works who my son…


upgrade turn signals on a 63 convertible

Posted by Brian Lydford on November 11, 2023 at 1:14pm 6 Comments

Hi all,

 I have a 63 series 62 convertible.

 Thought it would be a good idea to make the fin lights flash as well as tail/stop lights.

They did this in 64 i believe.

i replaced single filiment bulb holder in fin lamp, to a twin filiment.

ran a wire from the tail/stop lights to this extra filiment in the fin light.

its the pink wire on the color diagram i have. purple on passenger side.

Any how, yes it works and looks great, during the…



Posted by ANGELO MARTINEZ on July 23, 2023 at 10:44pm 2 Comments

  Hope someone can help me to find the harmonic balancer bolt for my 1964 Cadilac Deville 429 engine

in advance, thank you for your help.

Clock ‘64 DeVille

Posted by Matt Vander Hooven on July 23, 2023 at 7:36pm 2 Comments

Is there still a member in the Detroit area that refurbishes clocks?

Matt VH


  • Add Videos
  • View All

© 2023   Created by Jason Edge.   Powered by

Badges  |  Report an Issue  |  Terms of Service