General Discussion on Heat

[69.5Mav]

That is an old myth that people argue for the coolant side of the equation. But I never hear anyone state that you need to reduce the air flow across the radiator in order to get better cooling because the air is moving too fast. Intuitively everyone knows more air flow will increase cooling. It is the same on the coolant side of the radiator too. More coolant flow will aid cooling.

Amen to that, Bro
Removing the thermostat has ALWAYS resulted in lower coolant temps for me; my experiences have always been at "normal" speeds though, never a racing application.

I agree.

The only caveat I would add is that as you increase coolant flow rate you will reach a point of diminishing returns where any increase in coolant flow rate will produce minimal increases in cooling, assuming of course an ideal water pump that does not cavitations.

 

[MPGmustang]

wow, this is pretty deep and detailed, all of it, I'll be trying my own FiberGlass fan shroud. looks cheap.

I did find some one here in the valley that i'm tempted to drive to and have them measue it. but it's $100 if i let them build me one. cool side is it's alum.


the distance from my rad and AC is roughly 1.5 inches, decent space but not enough for a pusher. there is plenty of area for the air to go around the AC also,

the AC temp is 129 on cool mornings, roughly 95, and 136 on hot afternoons,
the top is 194 on hot hot day's and bottom is 180, but I still don't know unless i'm measuing myself. i'll get the guage after funds come in. hopefully i'll finish before school starts.

Thanks again for all this information!!!!

 

[80broncoman]

"Wetter water" is stuff that speed companies sell to improve their bottom line. They claim that the product absorbs heat faster. If that is true, it also loses heat slower. So, you pick up heat and carry it though the radiator, back to the engine.

No OEM manufacturer ever used "wetter water". More junk to waste money on, in my opinion.

Water wetter works in a very uniqe way. It reduces surface tension. Surface tension is what allows one to float a steel paper clip on water. It gets rid of the small air bubbles that develop and cling on the inside of the heads. These air bubbles do not transfer heat nearly as well as the coolant that replaces them.
The orignal only worked with water not coolant, I think they have another one that workes with anti-freeze now but it doesn'twork as well as the orignal.

 

[66 Fastback]

When water wetter first came out, I believe it was used with straight water, no glycol antifreeze. Plain water has better thermal efficiency than antifreeze and will lower operating temps. The knock back then was that water wetter did not have cold weather protection and limited corrosion inhibitors. If there is anything to the water wetter regarding the surface tension, it would reduce the thickness of the "boundary" layer on the surface of the tubes. A thinner boundary layer increases thermal efficiency slightly, but I suspect more benefit was derived from the fact that the mixture was nearly 100% water. On any tube, the flow velocity profile is greater in the middle of the tube and tapers off to near zero at the walls of the tube. If you can change the flow profile to have more fluid contacting the tube's wall, more heat will be able to transfer into the tube and out of the coolant at a faster rate.

There are also other products out there that are 100% propylene glycol. They claim that there is no corrosion since there is no water. It also has a higher boiling point and less tendency to cavitate. However, it has lower thermal efficiency than an ethylene glycol mixture. So it typically will operate at a higher temperature. If you egnine can handle the additional temp, there may be HP and efficiency gains in operating at the elevated temp. But the weak link in a lot of OEM cars are the hoses. Heat and pressure weaken the hoses.
Doug

 

[Explorer]

Royal Purple Ice is one that mixes with anti-freeze. I posted for comments about it on another forum and the consensus was yes it works. Results ranged from 7-15 degrees cooler using it. No personal experience, but had no negative results on it.

 

[MPGmustang]

update....

so a bit has changed, I have a 1800/2400cfm electric fan, with a fan shroud. comes on @ 169* and off @ 159* (so it's basically always on) and always on with AC.

around town I get hot agian, t-stat is 180 just installed 2 months ago. I run the 195* for winter as it didn't get hot enough.

town/idle/stop-and-go is fine, no problems with AC on, winter is fine no problems (town or hwy) BUT it creeps up in temp in sumer when I get on the hwy, as it hasn't hit 100* yet, I would like to find a solution.

you think this might be from a lower radiator hose colapsing? how do I tell? at temp it's firm as if the water cooling system has pressure.

if it's not this, a bigger radiator? I know I can get a 71 maverik 250 radiator to fit with no problem but just wanted to touch base with what you guys think if I "need" a bigger radiator or keep try'n something else.

just so you all know,
rad= 1yr
engine=6months
heater box=2yrs (water stop valve)

outside temps are 90+ today but it's done this even when it's 75* outside...

 

[Gene Fiore]

Richard, if you are having heat issues on the hwy then it's one of two things. Not enough air flowing thru the radiator ( unlikely at hwy speeds ) or the radiator can't dissipate the heat fast enough. I have been having these same issues on the hwy in warm weather. Here is what a good mechanic friend of mine emailed me about this:

Hi Gene,
I was thinking about what you said about your Maverick running hot. As far as thermostats go we are all aware that they open when the engine reaches the the temperature of the thermostat rating, 160, 180, 195, but that is not the only thing it does. The opening where the water goes through are different sizes. 160 larger, 180 smaller and 195 smallest. This acts as a restriction and controls the rate of coolant going through the radiator. If it moves too fast it will not dissipate the heat enough.

With newer cars running a radiator with less rows requires the 195 which would have a smaller opening causing the coolant to stay in the radiator longer. I had a lot of problems with the Corvetters because they would run a 160 thermostat and a 4 row radiator and the enging would run hot like the problem you are having. I would put a 195 back in (factory installed) and the problem would go away.

When you are running down the highway you do not need a fan, so this leads me to believe that the 180 thermostat may be the problem. I think the electric fans come on in a production car around 218 degrees but the calibration never corresponds to the actual reading with a aftermarket gauge.

The electric fan set will use less horse power and I just found out reading some article that a clutch fan can cost up to 12 HP. I don't think the ratio of anti freeze and water would make as much difference as a thermostat change. If you feel this could be a problem it would be worth changing the thermostat. If you choose to change the anti freeze mix don't make both chances at the same time, this way you can see what worked.

This is what I know about stats and I hope it can be of some help to you.

So I changed from my 180 to a 195 and drove out to Speedworld last Friday nite...it was about 95 degrees outside when I left the house. It seems to have helped some because the temp never got over about 205. When I drove down I-10 for the cruise on Central with the 180 tstat it was creeping past 210 or so. I think this is the best I can expect to see for my setup. Hope this helps.

 

[MPGmustang]

I wonder if it makes that big of a difference... what if the water is taking too long of a time to exit the engine, where the engine keeps the water longer because the t-stat can't "flow" fast enough at higher speeds. and your suggestion that the 180 flows too fast that the radiator can't cool it fast enough also makes sense...

well I finally got my self a mech temp guage, this past weekend on sunday (when it was really hot out) my temp rose to 220 with my 180 t-stat, I was driving 65-75 on the freeway, but intown it came down to 195, granted my AC is really nice as I always keep it on low, sometimes I turn off the compressor cause it's too cold... maybe I have too much free-on in my system for highway driving?

anyways, I don't think this temp spike is healthy for an alum head, I want to keep my temp in a smaller more controlled temp range. say 190-210 not 180-220

to do so I have been thinking about using a 24inch wide radiator, I'll cut the radiator support enough to alow airflow freely, for mounting I'm thinking a radiator braket from a 67-68mustang or 75granada, this way I won't need to worry about side bolts.

I figure if there is more water in the system and more radiator surface i'll be able to keep the 180* t-stat and control the temp's with the fan properly.

and last question, for disapating heat, copper or alum... reason I ask is cause the copper is stronger therefore can be thinner, where as alum needs thickness to be strong enough or as strong as copper. I think a copper efficency would last longer than alum efficency due to the fact the fins are weaker on the alum. but it's no doubt the alum can get rid of more heat more easily. so If i went for a daily driver and highway cruiser radiator, that lasts longer and efficient would be the copper?

what do you guy's think?

(do we have any dimond made radiators? lol)

 

[MPGmustang]

Well gene, I think i found it...

so, I got previous t-stats from checker, it looks to be 1.25-1.3 inches wide, both the 180 and 195, then I decided to go to napa, I found both 180 and 195 with a 1.06 diameter for the water flow, I have installed the napa one for now, but while instaling I have found another problem...

all my water pump changes and t-stat changes have always used rtv blue to seal it up, I didn't really let it cure much, just fill up and drive. well that has finally taken it's toll. I looked in the top of the radiator and found the top pasages clogged with rtv peices that have dislodged itself fo find it's way into the radiator. I have no idea how much is in the rad or the engine block, tomorrow I'll be flushing the entire system. I'll run clean hose water to flush the block, and run the radiator backwards till i'm happy that I got it all.

and I get to do this right before the race... >_<

so yes they do make different size t-stat's but only from different companies. I'll let you know how it holds up in the heat today/tomorrow and next week on my 1400mile road trip next week.

 

[MPGmustang]

UPDATE:

I thought I should update this, I have since found after this discussion that my CAM timing was 11.5* advanced by the engine rebuild shop. I have in sept 2011 re-degreed the cam to a healthy 4* advance.

also, have added electric fan, shroud, clean alum radiator. so far (pre 110+ heat) it has never given me any problems and with a temp guage I'm reading 180 on cold days, and 195-200 on hot days. running a 195 t-stat. the electric fan takes up over 77% of the radiator surface.


http://photobucket.com/mpgmustang_CoolingSystem

only this summer will show the heat changes. Hopefully I have covered the 'engine' heat transfer and have an adequate radiator.

 

[Xargon321]

ouch well at least you figured it out and corrected it!

 

[chad]

"I'll let you know how it holds up"

the saga continues.
lota info 4 me, dispels some myths too.
Thanks All.

Enjoy the trip, B safe.

 

[woodbutcher]

Hi all.One other trick that I found that works well.If your vehicle starts to overheat,shut off the AC and open the windows and turn on the HEATER full blast.Don`t forget the heater core is just another radiator.You WILL sweat like crazy,but thats easier and cheaper to fix than a new engine.Have had to use that little trick a few times in the past,and saw temp drops of as much as 25*.
Good luck.Have fun.Be safe.
Leo

 

[turbo2256b]

Difference between water in and water out refered to as Delta between them shoot for 10*.

How about your timing being off. A bit retarded or more creats heat. Usally takes a lot more advance to become way to hot compaired to retarded timing.

 

[MPGmustang]

and it keeps going...

finally have some real heat here in AZ... and humidity is 0 every summer... think someone mentioned humidity...

I don't think I'm getting enough air through the radiator. I know I'm transferring heat to the water beautifully and efficiently, but it comes down to the radiator.

the reason I think it's air, outside air is hot right now, but during the winter, my 195* t-stat stayed on 180* for short comutes, longer drives would go to 195* but traffic speeds would put it back to 180, think that's the breather hole leaking the good heat.
when it was cool, my 2400cfm fan did great. but as it is heating up, I toggle my ac off as engine coolant goes to 210*-230* with the AC, sure I can drive without AC, but I have AC cause I want AC!!

at speeds 60+, I'm having a heat issue 230*+ with AC LOW, turn off the fan and the temp climbs in summer/winter winter not much but summer it rockets hot. I won't use High at these speeds.
at speeds 30-55 if stay in 5th gear and give room between cars it's good 210* low AC, high I'll be 230* bad,
0-30mph 210 low, <230 high.

I think it's radiator heat transfer related.

temp gauge is mech, and plugged in the back of the head.

so plans
easy, turn off AC... umm, not an option, I'm spoiling myself here... this is veto'd

manageable, toggle AC compressor, yeah doing this now, not good enough! next...

Simple, by-pass heater core so water flows all the time... no hot spots. see if it 'helps' or fixes, doubt this... but worth a shot, again

body work, replace or modify valence for air dam... I can cut it, if I like it/helps, I can order a real air dam for $150 and have it painted to match.

EXTREME, rip out radiator, cut support for a 24inch cross flow, custom order 351ci alum rad but with i6 inlets, install dual 12inch fan setup and shroud to cover entire area, be able to run AC on high in 115* heat. Figure I'll spend close to $500 on this.


I'm going to go in order, simple first, body work, then extreme... I will stop sweating in summer with my AC on, if it was high I wouldn't sweat but low makes me sweat and AC off well, that's just uncalled for...