Author Topic: 428 overheating at idle  (Read 5092 times)

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dmann

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Re: 428 overheating at idle
« Reply #15 on: February 18, 2019, 09:55:37 PM »
I have an old Volvo that I recently put a new fan clutch on.  I switched to the "heavy duty" version of the clutch, but I think what I'm about to tell you is something to consider.

The old fan clutch seemed to work fine and also had plenty of drag, but I was replacing all of the cooling system parts so I went ahead with it.


When the car has been idling in traffic on a warm day at a stop light, the sound that the fan makes as I take off is very very noticeable.  The fan is exactly the same, the only difference is the clutch.  It sounds like a truck.  It moves that much more air.

If your vehicle is hot and you can't hear the fan really moving the air when you rev it (more air movement than when it was cool), then maybe the clutch is toast or it's not getting hot enough to activate.  My fan clutch needs to get pretty hot.  I don't have a temp gauge with degrees on it (it's factory), but it needs to really get warm before it really wakes up.

Once up to a decent speed the fan quiets down on my Volvo - and I believe that exactly how it was designed to work.  Driving gives enough airflow through the radiator that the clutch cools off (along with the coolant) and the clutch becomes free wheeling (or closer to it).

Is your radiator getting as hot as the engine itself?  Can you get a BBQ temp probe into the fins to see what it is reading?  The coolant on the hot side of your radiator really should be close to what it's running at near the temp sender in the engine.  If the radiator isn't getting hot that's a big problem.

I hope you find the issue, best of luck.

Leny Mason

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Re: 428 overheating at idle
« Reply #16 on: February 27, 2019, 08:51:15 AM »
Hi, on my 1969 428 Mustang I built in 1976, a few years ago it started to over heat in parades, as we where getting ready to go to the International Mustang Meet in Calgary Canada, I was looking everything over when I grabbed the water pump fan it was ready to fall off lucky, I put a water pump on that night we left in the morning, it has not heated up in parades at all, try a new water pump if you can. Leny Mason

Stangman

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Re: 428 overheating at idle
« Reply #17 on: February 27, 2019, 09:06:38 AM »
Whatever happened happystang is it happy yet. 8)

happystang

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Re: 428 overheating at idle
« Reply #18 on: March 02, 2019, 10:52:02 PM »
Hi everyone!

I've been down in Southern California for school and haven't had a chance to make the 300+ mile drive to work on the 428. I'll be back home in a couple weeks to screw around with it :). I've ordered a couple different fan clutches, hopefully one of them will work/continue to work!

If all goes well, I'll be bringing it back down with me for the rest of the semester (and the Fabulous Fords Forever show in Anaheim).

IMG_8876 by armon7, on Flickr

happystang

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Re: 428 overheating at idle
« Reply #19 on: March 17, 2019, 10:53:58 AM »
Okay guys, just following up- the overheating issue seems to be solved.

The replacement heavy duty Hayden 2765 fan clutch seemed to help a little bit, but the temperature still eventually crept up. I added some Water Wetter as a last ditch effort and maybe got a 2-3 degree improvement, but again the car would eventually get hotter than I'd like at idle. I ended up ordering a 17" high output Derale electric fan and a SPAL thermal relay kit. SPAL includes both a 30 and 40 amp fuse in their kit along with eyelet connectors, a fuse holder, all the wiring, thermostatic switch, and a bunch of other bits and pieces. The fan pulls around 23 amps- I found that the initial power spike on fan startup was too high for the recommended (per Derale) 30 amp fuse, so a 40 amp fuse was used instead. I attribute this to ditching the low speed setting and wiring the fan so that it immediately goes to high speed. The fan kicks in at 195* and shuts off at 185*. Problem solved!

The fan is off almost all of the time and only comes on at idle when needed. It's significantly quieter than the mechanical fan and I don't have to worry about losing any fingers. One thing I did notice however is how difficult it is to get hot air OUT of the engine bay as it takes longer for the fans to bring the temperature down with the hood closed. I'll try and get some pictures of the setup later today.

I took the fastback on a rather arduous cruise with a few mustang buddies yesterday and she ran flawlessly!

IMG_1865 by armon7, on Flickr

IMG_1897 by armon7, on Flickr

Faron

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Re: 428 overheating at idle
« Reply #20 on: March 17, 2019, 11:19:20 AM »
Do you have the water pump over or Under driven , All Fords are Over driven when they had AC , that being said I changed to an over driven water pump on my blown combo and it dropped almost 15 degrees at slow speeds , obviously you had an airflow problem , but spinning the water pump fan combo may have solved it as well

Bolted to Floor

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Re: 428 overheating at idle
« Reply #21 on: March 17, 2019, 01:26:11 PM »
Due to the tight compartment, big engine, and lots of heat......I opted for the 67 Shelby hood with scoop and “fish gills” on the sides. The gills do allow for a lot of hot air to escape. The gills will allow for water into the engine compartment on rainy days or wash days, if you are worried about that.

Others have made changes on the hood hinges to create an opening at the back of the hood for hot air to escape. I don’t remember if they stacked washers under the hinge bolts or something else. Someone should chime in.
John D -- 67 Mustang 390 5 speed