Cooling Question

[Stano]

I took my 67 for the first out of town run last night and it ran warmer than I am comfortable with. When I last ran this motor it hit about190-195 degrees, with a manual tranny and 3 row radiator and 17in flex fan, 195 thermostat. Now it is the same with the exceptions of 160 d thermostat, 18in clutch fan new 3 row and Th350 auto. It hit around 230+ on the highway. I can't have that. Too hot in my book. Any ideas? Never boiled over but that was cruising 65-70mph. Also I no longer have a heater in the truck. And the rear gear ratio is 3:73.

[crazy longhorn]

You will probably hear that this is a no no, but i run a flex a lite 18" diameter plastic fan. i have a 195 stat in my 383,& she runs consistant @ 185 on the road.......will go 200 idling in traffic on a 100 degree day. i also have 4.10 gears, so cruisin with the truckers is 4000 rpms@ 80 mph. I have had no luck with clutch fans,& only run a flex.......but i dont keep em too long,dont like the idea of a "grenade".........AL

[Longhorn Man]

I've always had good luck with clutch fans...and I do hate the 'swing blade' flex fans.
It sounds to me like your water pump is about to take a crap on you. Normally at freeway speeds, if your over heating, it is the lower rad hose collapsing, (check the inside of it for a spring) or a bad pump. It is getting all the air it could ever need at 60 MPH.

[Stano]

Well I got my flex fan in the first place cause everyone's like you need one, then after i got it everyones like get rid of that thing it will fly apart and tear stuff up. So I put in a new clutch fan and the darn thing is runnin hot meanwhile I got rid of the flex fan and now I am gonna git me another I believe. I built the truck to drive not for resting under the hood. I know several people who run flex fans and never no problems. The only ones I know of are the factory ones on a few dusters and cudas around here that went through the hoods and created some nice louvers. LOL

[RipMeyer]

IMO

A 160 thermostat wont allow the water in the radiator to cool enough in hot weather. Its always open. A 195 would be closed longer allowing the water in the radiator to cool longer.

Put the 180 or 195 back in. Also get a new radiator cap just to be sure. A funky one can cause trouble and you never suspect it.

Just my .02

[Andy4639]

First let me say that there is no short cuts in this area. Cooling is one of those area's you do what you have too. With that said:

• You need a fan shourd and clutch fan if a/c

• You need a good hose and cap on radiator.
• Change the thermstat back to a 195.

If you have all this and your not keeping cool then start checking what you already have, and I would start with the clutch fan, even if it's a new one. You should not get more than a half of a spin out of it when the motor is cool, if you get more than that is bad more than likely. If you don't have the fan shourd I would suggest getting one, it will help a whole lot in the engine cooling. I would also suggest looking at the radiator also and make sure you don't have anything jamed in the fins blocking the air flow. You would be suprised at what can get in there.

[mikep]

I run a 18 inch stainless steel flex fan and have never had a problem with it nor have I ever had a problem with any steel flex fan I have ever run in the past. Too many things to go wrong with a clutch fan in my book. I run a 180 thermostat with a 4 core radiator and a shroud and I have never gotten hotter than 180 even on a hot day with a fresh engine .

[Mudder]

And I'm having problems too. Only at higher RPM's and going down the highway. If and when I get my electric fan back I'll get it on and see what happens. If that dont work I'll go back to a clutch fan I guess. Having some fabs done to the fan itself.

[68 with 350 TPI]

To heck with a clutch fan or a flex fan.... GET A PAIR OF ELETRIC FANS!!!

And get a thermosat switch to turn the fan on and off where ever you want it.
I like on at 185 and off at 175

[TERRYP]

Newer big Fords have a nice dual electric fan setup, even has a shelf on top, but I am not sure they will clear a V8 in the V8 location

[TERRYP]

here's another

[XXL]

Without this devolving into a religious battle (too late? )... the factory tended to go with clutch fans, and they are significantly more expensive than flex fans. Based on that alone, it would seem that clutch fans are better than flex fans at cooling. Having said that... the factory typically goes with electrics now, and they are even more expensive than either clutch or flex, so I'm guessing that they must be even better.

My truck has a 33 year old clutch fan on it and it runs 185 all day long. That includes 2 summers ago when I was still in central Texas where you can fry your brain (or an egg, whichever you prefer) pretty easily in the afternoon heat.

Kenneth

[mikep]

Having run single and dual electric fans on a number of high performance cars its my personal feeling that they are next to worthless in anything over 250 horsepower. The manufacturers of them generally agree. Read their ratings on them. Theres no way you can get enough airflow through one of them at idle after a full power run or a long highway cruise to keep the coolant from boiling away. If you are running a performance converter absolutely forget about it. Ive pulled off a few electric fans so I could replace them with wide blade stainless flex fans and then my cooling problems went away.

Clutches on high quality flex fans dont go out in the middle of the desert.

[68 with 350 TPI]

I run eletric fans on my blower engine without any problems.

You may need to fab up a custom shroud for really high hp engines or decide if a push or pull fan will work better for what you have.


Plus there are many diffrent types of eletric fans out on the market with different CFM ratings.

Im sure a eletric fan off of a 405 hp Z06 vette works fine at that hp or we would hear about it by now.

But I do admit it took two eletric fans and a good radiator to keep the blower engine cool at 19lbs boost.

The trans has its own cooler/fan setup for the stall etc.

[Longhorn Man]

Maybe i just been real lucky, here's my combo that works in the muggy mid west, AND in the aformentioned central Tx. This set up has worked flawlessly since '97, holding a steady 100 - 110 MPH for about 25 miles, or towing a 16X50 foot modular home (only a few miles) in the tx heat. Freeway, or grid lock...I think you get the idea.
Stock no idea how old cast iron short pump.
New (in 2000) 3 core radiater from a '73 - '87 truck. (much cheaper than the 67 - 72 unit)
Stock '70 6 blade fan.
New (in 2000) generic parts store fan clutch. ($20 at the most).
Generic 160 degree T-stat.
Inline 6 fan shroud (nothing but a finger protector).
In the summer I run straight distilled water, and have seen a 10 degree temp decrease, and in the winter, I put the green stuff back in 50/50 with distilled water, and install a 195 T-stat so my heater will some what work. I even have to put cardboard (painted black) over the rad in the winter.
There was only once since i got this set up assembled that I have ever had a problem, and that was when i was haulin @ss and threw a belt. Got her up to about 260, and came out ok...even with the "crack prone" light casting 882 heads. (I know....I got lucky)
While my little 350 isn't a 12 second street terror, It does have some porting to the heads, a 501/500 lift (dunno the rest of the specs) cam that lopes like a top fueler (not quite), an Eldebrock performere RPM intake, and your other normall bolt ons. This thing is bogged down every day, trying to struggle over the 3.07 gears and way too low stall (1900) verter. It actually bogs from the effective load. (engine don't pull till 2000 RPM, and 'wakes up' at about 3000)
I know My combo doesn't make too much sence, but the 2 most over looked parts are the radiater, becouse you can't see the clogged pipes, and the water pump, becouse "if the fan isn't wobling, and the weep hole isn't weeping...it must be ok".
The 2 rules of thumb;
low RPM boil over (or too high for comfort) is fan related.
high RPM boil over (or too high for comfort) is normally coolant flow related.
Just generic rules, but 80% of the time...they are acurate.

[crazy longhorn]

The generic rules make good sence Longhorn.......another thought is the stat(not the heat rating), but that the new stat could be defective,maybe opened partway , then stuck? it wouldnt be the first bad one that i saw.....Al

[6869704X4]

Did you do anything to the grill that might be blocking airflow?
I read somewhere that at about 35mph or above you dont even need a fan. Like longhornmail said at 60 you should be getting all the air you'll ever need. Did your radiator sit for awhile and maybe grow some crud in it? I cleaned my 69 camaro cooling system by pouring some powered spic n span in the rad while it was running after the stat was open. Took it for a drive then drained and flushed the system. That was good for a 20 degree drop. Yea, you should have seen the crud that came out.

[Longhorn Man]

spic-n-span huh? I'll have to remember that one.
Also, if this is an A/C truck...look and see if your condnesor is clogged up...clean the fins, then yank the rad out and see if the rad its self can breath.

[Stano]

Well I appreciate all your advice and experiences but everyone has different ideas what works for them. And I guess I will have to figure out what works for me. I would like to stay away from electric fans because I can slap on another belt in the middle of nowhere, not that easy to find that certain mitsubishi fan motor if need arise. I have checked my lower hose and it does have the spring inside, water pump is new as is the radiator,thermostat. Fan clutch checks out as far as the cold spin thing goes. I will try a 180 or 195 stat again. I am about ready to rip off the front of the motor and go get all new stuff again and start over. LOL Thanks guys
Stano

[mikep]

OH Yeah. Check and make sure your radiator cap is good. I went through 2 schucks specials that wouldnt hold any pressure and I was getting hot. Your coolant sysytem has to hold pressure to work properly. I finally ended up getting an OEM one from the junkyard. problem solved

[Stano]

I borrowed a digital thermometer form a friend of mine today and tonight when I got home I jumped in the 67 and went for a drive. About 6 mile round trip. When I returned home my guage said 190d this is with a 160d stat. I popped the hood and checked the temp of stat housing and it said 161d. My sending unit is in the head for my guage and the temp was 191d or so. The guage is right but which should I rely on head temp or water temp at the stat housing? I need to figure this out before long cause I will be doing some highway driving and don't want to fry my engine. It is frustrating because they both seem to be right. 160d at stat and 190 at head(sending unit).

[Longhorn Man]

You think you might be having some detonation? A 30 degree differance is quite a bit

[Stano]

Well I thought about that, but also the water temp appears to be correct for the stat I have and the sending unit is located right at the heat source between number 1&3 cyl's. Maybe just the heat of combustion is messing with me? And only 1 1/4in from header tube too! Not elec guage btw.

[REPO1]

Guage readings are normally taken from the head. Are you sure that your water pump is even pumping? Sounds like you have no flow through the engine. I would make damn sure that you are not collapsing a hose. Most likely the bottom one.

[Stano]

I don't know I am seriously thinking about just pulling it all off and starting over. I have never had a problem like this before even when I took a bunch of junk and put it together to make an old beater or farm truck and trust me I have put a few of them together and used some real garbage parts. This is all recently new stuff. Top hose and water pump have about 1000 miles on them before they were pulled off and stored. And made sure there was nothing in them before installing. Radiator is new, lower hose w/spring inside, fan clutch, thermostat. It doesn't boil over or out, no missing coolant, temp climbs during acceleration on highway to about 220d+. Shaved heater.