On my 75 H/O 455 there's a pair of UNIMOTOR Electric Fans placed on the front of the radiator. Went for a short run today and checked out to see if they were actually turning and they were, but just barely.
I'm curious if I even need them? The speed they were turning, it would seem the two fans are almost blocking more air than what they are moving! Any suggestions, i.e. Remove them and go back to stock. Or leave them and get them operating correctly.?? the two fans show "Unimotor" on it and might possibly be add on fans as I have air conditioning. YET, it's still an aftermarket thing and wonder if it's needed. My temp gauge runs about 190 and up to about 210 on a hot day. I don't run the a/c that much and wonder if I'd be better off removing them entirely.

 

The car didn't need electric fans when it left the factory.

 

My thoughts exactly....just want to make sure I don't screw something up in reverse and have to reinstall.

 

Do you have the original fan?
Is the engine overheating?
I suspect this is not (necessarily) a 'show car' (judged event)?
I'd hate to see you open up a rabbit's hole.
Have you checked UNIMOTOR Electric Fan documentation installation instructions - maybe they aren't installed correctly - e.g. electrical wiring is not optimized?

 

Original fan is there and working. I will try and get documentation on the electric fans from the manufacturer but wonder whey they were even installed in the first place?
A/C was updated to the new regrigerant if that makes any difference. I'm thinking I can take it out as prior owner suspected he needed it and probably not necessary.

 

Nothing more than a 'hunch'. Maybe a P.O. installed the fans to correct some perceived cooling issue; then....corrected the overheating issue (elsewhere) but didn't bother to remove them after resolving the overheating issue elsewhere. Who knows, right?

 

↑ On the money Vintage Chief. I wrote my post before reading yours, and saw what you wrote on preview post. So sorry to essentially repeat what you said.

Yes, hard to tell what prior motivation was without 1st hand knowledge.

Maybe a previous owner was overly concerned about overheating. Or a gauge was giving them false readings that raised their concern, eventually was replaced and the fans stayed... Maybe the fan clutch was slipping without realizing and the fans were added as a indirect band aid. Under the pretense that the factory fan wasn't sufficient. Etc , etc, ...

One thing is for sure. Unplugging them should answer your question pretty quickly.

 

Auxiliary electric fans could be needed with R134A refrigerant in a very hot (like Arizona) environment. I was told by a local AC shop that with ambient temperatures in the 110 range, the compressor head pressure with R134A can get high enough to cause the compressor front seal to fail. In that situation, an electric fan is recommended for additional cooling.

Since you are in Minnesota, I doubt the above applies to you.

 

You mentioned that you took a test drive and your temperature hovered around 190*. What coolant temperature gauge do you have?

 

Norm:
Went for a short run yesterday, engine temp on the gauge showed roughly 190. On a longer run at 60mph, temp reached about 210. It's not a show car, just want to rid my car of stuff that isn't needed and clean up the wiring. I think I'll disconnect the fans and take it for a spin and see what happens. Original set up did not have a fuse, ran directly off the battery. Main question was/is the 455 engine prone to overheating & hence the added fans or should I also be looking at the thermostat and water pump for issues!

 

Personally, I've owned one 455 engine (from 1976 - 1982) equipped in a 1972 4-4-2. It ran (generally) between 190°F - 210°F equipped w/ a 195°F thermostat. I ran this car street hard (both interstate & town) - nothing competition (e.g. strip or otherwise). I was in the USAF when I bought this car - I was OCD on maintenance at the (Norton AFB, CA) on-base vehicle shop. That engine never overheated (boiled over) in six yrs. ownership. I don't have experience for any 455 outside what I personally owned - save for the hours spent helping others w/ their 455 engines. I was meticulous (OCD) w/ tune-up specifications & maintenance schedules. I can't say w/ any certainty if a 455 engine is prone to overheating for any model &/or model year.

I would think two electric fans sitting in front of the radiator at road speeds would hinder cooling by limiting air flow into the radiator? If you reconfigure air flow (dynamics) by inserting two additional fans placed in front of the radiator I'd guess you're limiting air flow & certainly changing the dynamics of air flow from what was originally designed.

I think use of an IR temperature gun is better than a gauge for accuracy. Point it at the thermostat housing.
Tune-up specifications, Dwell, both advanced/retarded conditions can influence engine temperature.

IMO, if you aren't boiling over and remaining w/in a 190°F - 210°F range I'm not certain there's an issue, per se.
I do think removing those hindrances (electric fans) to air flow could lower the overall temp at road speed.

 

Thanks for all the replies: Just took the car out now and I disconnected the electric fans (pulled the fuse). Temp stayed in what I would say is the normal range (rally temp gauge reads 100/210/250. ) So not reallly a linear reading as lower half scale is 110 degrees difference and then the second half reads from 210 to 250.. I'd say I was running roughly 185 degrees and never reached the 210 mark. It's a nice cool morning here but my gut tells me I should rip those electric fans out which I will do later today.
I will take my hand held temp gauge as you suggested and take a reading after I get those fans removed. Appreciate the help.
Bob

 

Bob, a factory Rallye gauge is going to be your least accurate way of measuring engine temp. I would plumb in a quality gauge, at least until you get this sorted, and confirm with IR gun. My concern would be that PO hooked up electric fans as a bandaid solution to a problem that may not yet be solved.

 

Upon a closer look....
There's a condenser in fron of the radiator that the set of electric fans are attached to!
There's also a little relay that turns on the fans. I wonder if this was all part of the a/c upgrade to the new refrigerant!

 

Ken
Thanks....this is what I'm finding upon delving into this. The a/c was coverted to the new R134A refrigerant AND the car came from South Carolina supposedly.
SO, I'm now finding this was all part of that conversion and other than having to rewire what I removed this a.m., I'll have to leave it alone.
Bob

 

It still shouldn't be needed. If the car runs hotter at speed than it does at idle, that typically indicates that the radiator is plugged. I had a GM truck once that had this problem. The bottom third of the radiator stayed cool to the touch when the truck was overheating due to the sludge in the tubes. A new radiator fixed the problem.

 

When my wife and I drove to the Nationals last year in Springfield (from Texas), my 75 W30 ran about 220° with the AC on. I know people say that is okay but I am old school and like it a little cooler. I replaced the radiator with a Cold Case radiator and it dropped the temp about 20°. I have the stock fan and shroud. The fan was a drop-in. I only had to bend one of the coolant lines slightly. I am very happy with it.

 

The cfm rating of most aftermarket fans is extremely optimistic. Either buy the high dollar Spal fans, or adapt a EOM fan from a similar sized late model car.

Of course, if the car doesn’t get hot with the factory fan, don’t bother. If it ain’t broke don’t fix it.

 

I would think a 160/180 stat with a Cold Case radiator would easily get your temps down and make you feel better about it. I use Cold Case on all my cars with the dual fan kit. Everybody runs 175 ish no matter how hot the day. The 66 had to have the Fast Monty shroud with the Spal fans to get keep her cool but she's a little hot head with 11.5 ish : 1 compression and 3.89 gears.

 

The a/c was converted to the new refrigerant. Ran the car today, temp gauge showed approx 200 degrees so suspecting a 195 degree thermostat installed. The trip was about 70 miles total. I did kick the a/c on for a bit and the temp rose about 5-10 degrees, The fans apparently were part of the conversion to the new refrigerant. so will have to leave that in place. My little digital temp gauge showed that the termp gauge is pretty close to correct.. SO...is this within normal range or should I keep digging for issues.? Starting out and running at 55 to 60mph/ rpms about 2300 the temp gauge was hovering about 195.

 

What is the ambient temperature in Minnesota these days?

 

Thats about as normal as you can get.

 

Had a small heatwave and it was like 88 yesterday!

 

Thanks, this seems to be the case......I think I'll start with flushing the radiator and see what happens! Good suggestion..

 

That’s very nice compared to here - we had a cool front that dropped us down to just below 100.

 

Yes, that's perfect.

I wouldn't overly worry about that with a top of the line car like yours. If everything is functioning correctly a 1975 W30 is lacking nothing as far as functionality. Its 455 was/is still a superb engine that is not hindered from running on the warm side, if that were to occur. It will hold up as well as it did in 1968. In case that is your concern. The model was detuned versus earlier versions but not compromised.