67 GTX - Texas Cooling Adventures

[TxDon]

I've owned my car about a year and a half now and have worked my way through a few teething and tuning issues to the point that it is now running well. One semi-issue since I got it has been cooling issues during the Hell we call Texas summer. The mechanical temp gauge shows the normal warmed up temp to be 185 - 190, most of the year it may go up to 200 sitting at a stop but will go back down quickly at cruise. In the summer temps with the A/C on it goes up to 210-215 and doesn't drop below 200. Now the factory temp gauge which is still connected stays a bit over the halfway mark and it has never boiled over but it seems too hot to me.

The radiator is an ECP aluminum 26" by 2 1/2" deep core with a 16 lb. cap. The fan is a fixed 18" diameter 7 blade unit with what appears to be a factory plastic shroud with a fan opening of 22". After doing a lot of research including many searches here it seemed like a larger diameter fan with a thermal clutch may help. I found a unit on Ebay, a 20" 7-blade fan with PN 3462186 and larger HD cooling shaped blades, that was supposedly from a later 70s Roadrunner with a 400 engine. I tried putting this on with the stock fan clutch but the fan blades hit the projecting lower rad tank and would not turn so it has been sitting in my shed. A few days ago I saw a post on here about the new low profile clutch from Hayden:

http://www.forbbodiesonly.com/moparforum/threads/hayden-fan-clutch-low-profile.115490/

I'm thinking of trying one of these, dimensionally I think it will work. Has anyone else done a fan upgrade like this and if so what were the results?

 

[coloradodave]

Don, If it never goes beyond 210-215* in the summer with the A/C on, you don't have a problem. I know everybody wants to see 180-190* all the time but you can spend a lot of money and time trying to fix a non-existent problem, and may never get there. Just look at it as the 'new normal'... JMO
BTW, I don't think that short Hayden clutch was meant to swing a 20" fan...

 

[TxDon]

Don, If it never goes beyond 210-215* in the summer with the A/C on, you don't have a problem. I know everybody wants to see 180-190* all the time but you can spend a lot of money and time trying to fix a non-existent problem, and may never get there. Just look at it as the 'new normal'... JMO
BTW, I don't think that short Hayden clutch was meant to swing a 20" fan...

I'm not sure I could say it "never" would go above 215, especially if I got stuck in slow moving traffic. I'm looking for more reserve cooling help and I know any factory A/C car would have a better designed fan and a thermal clutch. As far as the Hayden, why do you say it won't handle the 20" fan? The fan I have has aluminum blades so I doubt it weighs more than the steel one on the car now.

 

[miller]

Hell we call Texas summer

Heh...like that one! At an airshow, years ago, had a air race team out of the California desert. Heck, only 100...they used to 115 out there...could not believe it was sooo hot here! Had to keep those boys watered down.

One thing I've read about (here), and keeping in mind, is someone suggested using a 'dummy' thermostat. Simply knocking out the center, only using the main flange. Makes some resistance on the flow, but full time flow. Just tossing ideas around.

 

[TxDon]

Thanks Miller, I think I want to keep the thermostat for now but may look at putting in a lower temp one later.

I did finish one upgrade I had been working on, a coolant recovery system. After a lot of searching I found a long and skinny recovery tank from a 90s Mitsubishi that fit in nicely next to the radiator on the drivers side. I switched the rad cap for a vented one and now this let me fill the rad all the way to the top for a little extra capacity with no puking on the ground.

 

[TxDon]

There was a longer writeup on the short shaft Hayden fan clutch on the FABO forum, has anyone used this with a high pitch 20" fan like I showed above?

http://www.forabodiesonly.com/mopar/threads/short-shaft-fan-clutch.333873/

 

[TxDon]

Anybody?

 

[Cornpatch MO]

Keep in mind, a thermostat with lower numbers only mean that is the temp at which the thermo opens. If you are at 210 degree coolant temp with a 195 degree thermo, nothing below a 195 is going to make your water cooler. ..........................MO

 

[Gpuller]

Think that HD Hayden clutch is pretty new. It might take a little bit for them to be in service.
I tried swapping from a Flex-A-Light flex fan to a Mopar 215 fan and Jag clutch. That combo wouldn't keep temps as cool as the flex fan. I went back to the flex fan.
The standard duty clutch turns 60-70% of shaft speed when engaged. HD is 70-90%.

 

[TxDon]

Keep in mind, a thermostat with lower numbers only mean that is the temp at which the thermo opens. If you are at 210 degree coolant temp with a 195 degree thermo, nothing below a 195 is going to make your water cooler. ..........................MO

Yeah, I know that. I'm not really planning to do anything with the thermostat but I do think moving more air through the radiator would help.

 

[Dennis H]

I'm late on this, and always say the same thing. I like copper. As far as a recovery tank, when leaving 2 1/2 inches to the neck, never any overflow to the ground after proper burping. 180 Stant Superstat.

 

[Ranger16]

A couple of questions I have not seen asked are how old is the stat?
Was it tested?
Is it a good brand name stat or an AutoZone Don'Last product?

 

[Sonny Black]

Had the same problem....so, radiator rebuild, High (VOLUME)Performance Water Pump, block flush, & added WaterWetter.....no problems now ,so far.....

so, then I ran it without the new cap,(so no air bubble) but did not tighten it down right and spit antifreeze all over the Fu#n place!....Sonny was pissed!...but it runs cool....now clean up(repaint valve covers etc) antifreeze baked on, shoot!...hope this helps

 

[67GTX440]

So what is the proper burping procedure? I was used to this on my Viper where the radiator was lower than the rngine block. On my 67 GTX I have just squeezed the radiator hoses to see if that lowered radiator level from air being released and run the car up to temperature beyond thermostat opening and then let cool and added coolant to radiator three times until radiator remained full after cool down.

 

[Ranger16]

It should purge itself after a good run. Any air in the system should get pushed through along with the coolant and once in the radiator, migrate to the top. Any excess (if filled too high) will be purged via the cap vent.

 

[Mike67]

Some shops use a vacuum pump that also ties into a fill valve. The system is evacuated, just like a refrigerant system, and at a certain hg, they open the valve and the coolant fills the system completely since there are no air pockets .

 

[coloradodave]

"As far as the Hayden, why do you say it won't handle the 20" fan? The fan I have has aluminum blades so I doubt it weighs more than the steel one on the car now."

Don,
I don't know for a fact that the 20" fan would be a problem, just thinking out loud. BTW, I believe the original application for that short Hayden clutch was for a Jaguar plastic fan... I once witnessed an aluminum/steel Flex-o-lite fan exit a vehicle's hood when a clutch failed. It wasn't a pretty sight...

 

[cdr]

how is the distributor set up. initial timing,total,vac advance,?

 

[CoronetDarter]

Going back to your OP, you're on the right track attempting to cover the entire shroud opening with the larger diameter fan. How much do the fan blades rub? If only slightly I would first try tweaking the blades to make it fit because that looks like a stout setup. Can't see in your photos so I have to ask - the car has the rubber rad gasket attached to the hood and air dam at the bottom between the rad and grille? With the car idling in park and the fan rotating, can the incoming airflow hold a piece of paper against the radiator?

I had the same issues as you on my Coronet; new rad from Glen-Ray, 18" direct drive fan, shroud, high flow water pump. Car ran at 180* on the freeway in 100* heat, but climbed to 215* (and climbing) in stop-n-go traffic. Replaced the original with an unknown-make, 18 1/2", 5 bladed steel fan w/clutch. Had to tweak the blades slightly because the trailing edge of the blades hit the after-market A/C compressor. Now the highest temp recorded in traffic is 190* and quickly drops to low 180's once moving again. BTW, the current fan holds up a Mopar Muscle magazine at idle (pics are in my resto thread).

 

[440+6]

You say you have 18 inch fan and 22 opening, that may be your problem, 18 inch fan should have a 20 inch opening