Coolant Question

Discussion in 'Fox 5.0 Mustang Tech' started by SoFlStang, Jul 6, 2013.

  1. Probably a stupid question, but reading about different coolants online has me a bit confused. In my other ford (a focus) I use the normal good for all makes and models green prestone coolant. However, as I was reading about coolant capacity for my fox, I read that I should not use the all make and model coolants. Also read not to do the 50/50 mix, but to use more water then coolant since I live in south florida and water is better at handling the heat, the coolant just helps keep the vapor point down. Right now, it appears I am running plain water. My radiator appears to be new, as it looks new and the rest of my engine doesn't, also the heater core has been bypassed. I am also running a electric fan which the previous owner wired to run all the time the engine is on. So, what do you guys use in your cars? Oh, on a side note, what is the average running temp on these cars? When I run mine, usually I get right on the highway and it'll get to about 240 before it drops and stabilizes around 190-210 on an aftermarket gauge.
  2. that thing shouldn't run near that hot. I would look at starting with changing out the T stat and flushing the system. if it still runs hot I would look at radiator flow. it should not run that hot on the freeway with pleanty of airflow so im assuming the fan is ok.
  3. What would be the ideal operating temperature, while doing 70mph on the highway?
  4. even with a stock 192* T-stat in the heat no more than 195. My car has always run about 10* less than whatever T stat was in it. the fact that it goes up to 240* before cooling down is a problem.
  5. Thanks, I will go ahead and replace the thermostat. Should I stay with the stock 192 temp or go with the 180? Also, is the 'all makes all model' coolant ok to use?

    Edit: from reading a bunch of posts, I am going to go with the 180 mr. gasket thermostat
  6. Mine runs way over the stock guages half way point on desert road trips... mind you it's 120 deg's outside, and on the cajon pass which is a notorious hilly road headed to Vegas off of the 15 freeway. As long as it's under 85 outside the car stays cool, anything above that and the underhood heat is pretty bad, you can feel the exhaust heat through the floorboard. I was thinking of flushing system, changing stat, and maybe adding an external oil cooler and eventually a larger oil pan. Any thoughts guys? All the Mustangs I've ever had with any engine mods above the typical bolt ons always seem to add a significant amount of heat, and end up going through radiators, even after having custom radiators built they still barely keep the car cool on a hot day.
  7. any coolant is fine as long as you flush the system. the 180 works well. i don't daily drive mine so i normally run a moroso restrictor, but right now i have a 160 in it. when its 105 here my car still runs about 160* with a 160 t stat or restrictor. normally between 140-150 in cooler weather. back when i ran a 180* even with the turbo making a ton of heat it only ran 170* in 90-95* and about 185 in the heat of the day at 105-110 here in dallas.
  8. Sofi
    I'd spend the money on a massive aluminum radiator.

    The pan is great and all, but it's not going in with the engine in the car.

    Sofistang, the 180 mr gasket is easily my favorite.
    Sounds like your current stat is sticking then suddenly opening, a little air in the system could cause the same effect too.
    Do the stat change then go from there.
  9. soflastang,

    I'm in South Florida as well. If I can make some suggestions.

    1. You want to run some coolant with the water. Running 100% water is ok for racing but I would not recommend it for a DD, as the coolant has anti corrosion and lubricants in it.
    2. Your fan should not be running 100% of the time. First, it is pointless having the fan on at highway speeds. Second, it will lessen the life of the fan.
    3. Stick with the stock 192 stat. Contrary to what some people think, putting in a colder stat does not make your car run cooler. In fact, it can often make the car less efficient and run run warmer as a colder stat does not hold back the coolant long enough before opening it up.
    4. Your car should not be running that hot . My car with a Modine 2 row copper radiator, stock H2O pump and a Taurus fan will run just above the A in the gauge after the stat opens, and that is with U/D pullies. I run 50/50 coolant and water- use only distilled water as tap water has impurities.

    Quick tip, Normally if the car is running hot at highway speed, normally that is a restriction problem- airflow - radiator clogged, leaking, or tired. Check the front of the radiator for restrictions like debris that can cause the radiator to run less efficient. Remove the radiator cap when you start the car up and when the stat opens you should see the coolant moving across the top of the radiator.Also could be a bad water pump not pushing enough coolant- look for water dripping out of the weep hole either on the top or bottom of the front of the pump.

    If it is running hot at idle or in the city, that is normally a fan not cooling sufficient. What kind of fan do you have? Does it have a shroud?Is the overflow tank present and properly hooked up?

    Hope this helps
  10. I would experiment with the given vehicle to see what makes it run coolest. In the DFW area I run a 160* or a restrictor and it runs 20-30* cooler than a 180*. and the 180s run cooler than the stock T stat. and that's in the summer. I do this to keep detonation at bay. Depending on the environment and the combination might have different results. ive never been to your part of FL, but im pretty sure its more humid there than here. Im not sure how the extra humidity would effect your cooling efficiency, but it probably doesnt help matters. I will say this, on our high compression big motors they cool the best with all the flow they can get. I personally don't buy into the whole keeping the coolant in the motor longer theory because the hotter the coolant gets the less heat transfer occurs.
  11. I notice people in brand new cars overheating on the side of the road all the time headed to vegas
  12. maybe something to do with the new cars having to run at around 210* in normal to cold weather in order to help burn off hydrocarbons to meet emissions standards. drove my 93 in 110* heat last summer and it never went over 190*.
  13. Glad that is working for you but it doesn't change the rules of thermodynamics. Yes, the coolant may be running through the radiator faster, but that also means it is running through the water passages in the motor faster, therefore the coolant is not given sufficient time to "absorb" the heat from the motor. The engine coolant temperature may be lower, but the combustion temperature will be higher, which can lead to more detonation and damage. By running the coolant too quickly through the water passages in the motor, this is reducing the overall efficiency.

    If I can elaborate a little, with too low an operating temperature stat the engine can build heat faster than the radiator can dissipate, and this causes the thermostat to cycle only a few times, then it stays open and opens wider and wider increasing the amount of flow through the radiator as the heat builds. The coolant is flowing so fast through the radiator that the fan and/or air coming through the radiator cannot properly cool it. By going to a higher temperature opening thermostat, this will increase the temperature differential between ambient air temperature and the coolant temperature removing more heat from the coolant and a more regulated system. If you installed a larger sized or aluminum radiator you can probably run a 180 thermostat but I would still recommend for most people the 192.

    Now you are much more above sea level than I am so that may reduce the boiling point of the coolant and therefore the 180 is warranted. Here at 10 feet above sea level in S Fla that isn't an issue.

  14. like I said above you may have to play around to find what works best. lets define the rate that is considered too fast. the coolant passages themselves are a restriction. If the coolant were traveling at too high of a rate to cool the engine it would still have a detonation problem because you would still have the same hot spots which cause preignition. lower the temp and the preignition is gone and that can be verified by reading the spark plugs. I understand what you are saying and I am sure there is a point where the coolant can have too high a rate of flow, but I have not seen it happen in the real world to this point. which is why you should play with it. We are only about 500 ft above sea level. Physics also dictates that conduction will happen as long as there is a difference in temp between the hot side and the cold side. the larger the difference the faster the rate of conduction. If the radiator can 'keep up' by keeping coolant temp to a minimum (which can be verified with an inferred heat gun on the lower hose) then the more cold coolant you run through the engine to more heat transfer will occur. if you burn your hand, do you stick in a pot of 100* water or do you run it under cold flowing water?

    IMO the best way to determine what T stat or restrictor is correct for the application would be to try all of them, take your actual coolant temp at the t stat housing and subtract your coolant temp of your lower radiator hose from that and go with the greatest difference. but that's just me. the radiator will only cool it down so much. the hotter the coolant going into the radiator the more difficult it will be for it to pull the heat out. not to mention that my experience is that the lower temp t stats cool down faster, and the restrictors cool down even faster still.
  15. So I went and picked up a 180 degree Duracraft, since the only ones they had from Mr Gasket at the parts store was high performance and I read that let alot of coolant by even when closed. It has the little vent hole and was made by motorad. When I removed the tstat housing, I found there was no thermostat there, just alot of silicone. I cleaned it all off, and installed the new tstat with a felpro gasket. Put in conventional green coolant mixed with water and started it up. I think I got any air out, left the cap off and filled it as the water went down. Put the cap on and took it for a spin, temp gauge showed it went up to 200, then dropped down to 185-190 on the local streets. Gonna check the coolant level when it cools off and see how driving it on the highway tomorrow goes. So far, no leaks.

    Not sure what was causing the temp to go up to 250 before and then drop since there was not tstat installed, unless maybe there was an air bubble somewhere?
  16. that's possible
  17. Antifreeze is also anticorrosion and ANTI boil over. It raises the boiling point of your coolant so along with a good radiator cap to raise system pressure, they help keep your car off the side of the road.

    I would never run straight water. The different metals and tap water will act like a battery with electrolyte and eat up your motor and radiator.

    There is a better style thermostat than the stainless plate with a washer run by a spring. These can be forced closed under high RPM pressure. Someone (I think maybe GMB) makes a high flow thermostat that rotates open and closed. No closing at 5k rpm.
  18. I do not like it going to 240 deg before settling down to where it should be. Check for airflow and proper shrouding. If it settles down on the highway, and runs hot going slower, the electric fans are not doing their jobs. But that they run all the time has me also concerned. Are they wired wrong or is the temp sensor set wrong or shot?

  19. Got one, but it's older, most likely needs to be flushed and/or re-cored.... think the stat or pump is on the way out, wouldn't surprise me one bit as everything else seems to be failing lately.
  20. It's probably wired directly to a key ON power source so it's always on as long as the key is. I've seen so many freaking vehicles rigged up like this in my parts. It's ridiculous