running a little hot

[DieselSpider]

+1 on the cooling system flush every two years. If you flush the system every two years I'm not even sure it needs the vinegar step.

The rub is you usually won't really know it needed it the last time until the damage is already done. I will also use a shop vac to evacuate a system I am unsure of to ensure I get as much of the flush and sediment out. What are the chances that near to 40 year old cars went beyond two years between flushes a few times and need a little TLC?

[brackie1]

I am looking for a 140 degree radiator cooling fan switch. I used to see them at the various parts houses that we all use, but now I can not find any. Does anyone know where I can find one.

[RRoller123]

Follow up: I put the Purple Ice coolant additive in with a 50/50 anti-freeze premix, and it does generally run cooler, although I can't give actual data. But definitely a little cooler overall. I am running '80FI, AR Aluminum radiator, Mark's 274FI cams, AR large SS valve ported head, standard compression (for the time being), standard 4-2-1 exhaust, standard ignition timing advance on Computronics DIS4.

Pete

[Dawgme85]

50/50 ethylene-glycol/water coolant (antifreeze) has a boiling point of ~223 deg F. Adding a14 psi radiator cap raises the boiling point to above 250 deg F. Operating as high as 240 deg (briefly) will not damage the engine. By switching the fan on at 140 deg, all you'll accomplish is running the fan pretty much full time, which will eventually cause the fan to fail and the engine to overheat anyway.
The goal is to avoid boiling the coolant, which causes catastrophic engine overheating when the liquid coolant is replaced by air in the system. Air is not a good cooling fluid in a system designed to utilize water or antifreeze. Think of what happens to a pan of boiling water after the water has boiled away. Not good for the pan. The same holds true for an engine.
Unless you are regularly overheating to the point of causing the idiot light to come on, there should be no need to modify the cooling system and, even if that's the case (assuming all else is in good working order), the best option would probably be a bigger radiator or fan to transfer more heat away from the coolant, in my opinion (as a mechanical engineer). Attempting to lower the normal operating temperature to below ~175-210 deg is not the solution IMO.

http://auto.howstuffworks.com/cooling-system3.htm

[Dawgme85]

After doing a bit of research into the Evans product I found that, while it has a boiling point of 375 deg F, it only has a specific heat of about 57% that of water* (2633 J/Kg-K vs 4208 J/Kg-K @ 194 deg F), meaning that it is actually less efficient at removing heat from the engine than antifreeze. So, even though it has a higher boiling point, the coolant temp will actually run hotter, for the same amount of heat transfer. As I explained above, it's not temperature that kills an engine, it's actually the boiling of the coolant that causes engine damage. If you have a cooling system problem, fix it properly, and run good, clean antifreeze in the system for the best results. There's a reason cars are designed to use antifreeze as a coolant.
All the best,

LeRoy

*-Antifreeze actually has a specific heat of ~3720 J/Kg-K, not as good as water, but still better than Evans waterless.

[So Cal Mark]

140F is too cold of a temperature for an engine, it needs to be in the 160-180F range

[klweimer]

I'll toss in my 2 cents on the Evans coolant and what I've found. I rebuilt the entire engine, radiator, heater core, etc this last year and went with the Evans, as everything was dry so no issues with residual water. Since then I've had a devil of a time with small leaks everywhere. I've been working on car engines for 40+ years and have never had so much trouble getting everything leak free (I hate leaks!). I too found some grey sludge when I had to drain the system once or twice and given the cost of the coolant, you have to work very hard to save a much as you can if you have to drain and refill for any reason. I solved the gray sludge concern by putting a WIX fuel filter on the throttle plate heater hose that recircs coolant from the system. Picked up plenty of gunk while running it for a few weeks. I now have pretty much all my head studs leaking slightly, so I've had it with the Evans and going back to conventional coolant. Perhaps in a new vehicle that was designed to run higher cooling system temps and pressure it would be OK, but I would not recommend, based on my personal experience.
Kirk

[brackie1]

This all has been a great conversation and learning experience.

[DieselSpider]

Follow up: I put the Purple Ice coolant additive in with a 50/50 anti-freeze premix, and it does generally run cooler, although I can't give actual data. But definitely a little cooler overall. I am running '80FI, AR Aluminum radiator, Mark's 274FI cams, AR large SS valve ported head, standard compression (for the time being), standard 4-2-1 exhaust, standard ignition timing advance on Computronics DIS4.

Pete

That bit of extra efficiency at heat transfer helps. The biggest difference you may note is that when the fan kicks in that it will shut off more quickly so that your engine temperature is more consistent.

[RRoller123]

Exactly, seems to dampen the swings a bit. And like everywhere else, it has been really hot here lately. Since adding it, I have been able to turn off the defroster heat, which I tend to run in warm weather to help cool the engine. The side window vents pull the hot air out and it is hardly noticeable in the cabin.

Pete

[Nitrate]

Evans actually makes the cooling system run hotter. With today's oils an engine can run very hot which is a plus for efficiently, and not a problem for the mechanical aspects of the engine.The Achilles heal with antifreeze/water is that you can't take advantage of allowing the engine to reach its peak heat efficiency which is above the boiling point/blowoff point of the antifreeze mixture. Evens coolant can allow the engine to run at higher temps to take advantage of the higher limits of synthetic oil. Heat does not hurt an engine it can make it more efficient. RB

[So Cal Mark]

you'll open a can of worms with that logic of heat=efficiency

[Dawgme85]

Performance engines certainly want to run cooler (within limitations) to achieve the best performance, as Mark correctly pointed out above, but when sitting in traffic on a hot day the main thing is to avoid boiling over, which can lead to blown head gaskets and more serious engine damage. Different criteria for different situations, both valid.

[DieselSpider]

you'll open a can of worms with that logic of heat=efficiency

On an engine without pre-detonation sensors and such or a cold air intake system you want to be careful about just changing out to a waterless coolant and a hotter t-stat. Even on a car with all the sensors and computerization if you put in a waterless coolant and hotter stat, then the computer will likely run the engine rich to cool it down impacting performance and fuel efficiency. Overcome that and then Ceramic engine technology becomes a consideration to help cope with hot spots.

Yes it can be quite a large can of worms.

[Dawgme85]

Just an FYI, but yesterday a friend and I took SHELOB out for a drive in 95+ degree temps. While driving on open roads, the temp stayed in the 175-180 range, and when driving a bit more spirited, it crept to about 185, but didn't hit 190. When we got into stop and go traffic, the temp would rise to about 195, at which point the fan would kick in, and as soon as we started moving again, the temp would drop right back down to about 180-185, or so. I would say this is about normal, considering the relatively high (for PNW) ambient temperature. YMMV.