Couple coolant system q's

[haromaster87]

Alright, did some searchin but couldn't find a straight answer. Anyway, I was headin home today goin down the highway and it was about 3:30pm in a Fl afternoon- HOT. lol So I was runnin about 195* and I did a little 4th gear pull and the car creeped up to 200* pretty quick. As soon as I backed off of it, it came back down to 195. This prolly isn't that bad but I don't like the car gettin that hot. If I swap in a lower temp thermostat can it help the car run a bit cooler? It's got the factory thermo in there now which I think is a 195. So if I go to a 160 or a 180 will the car run a bit cooler? And since it's ussually pretty hot here, what would I be better off with? 160 or 180? Also, before I did some work on the coolant system it seemed to work a bit better. The only thing I know of that changed is it's not quite a perfect 50/50 mix in there. It's somewhere around a 50/50 but not exactly. If anything there'd be more water then coolant. Can that cause the car to have a slightly harder time keepin cool? Also, when I replaced the hose that was used to bypass the heater core I replaced it with the same thing. It was just a piece of hose bent in half, which causes it to crimp up. The old one worked like that but idk. Is there a better alternative to this? Btw, '86 5.0

Any help appreciated!

Thanks,
Tony

[85stanggt]

I run the stock stuff without a problem. Been driving with that down in Miami/Ft. Lauderdale for 23 years. My coolant temp right out of the thermostat housing is right around 200* with a 192* stat. I think that's what it's supposed to be.

[gdniel]

I run a 180, no problems. As hot as it is right now, yesterday I ran my car hard for about 10-12 miles on I-95 and it got a little hot around 195 with a 180 stat. It came back down within a few miles of normal driving. Mine only does this when it is 95+ outside. The coolant mix is fine, I'd leave it alone.

[795.0pacecar]

200º is perfectly fine and normal for these engines, but if you want to run a cooler thermostat, go no lower than a 180º.

[JACook]

If the engine temp is creeping up under load, a cooler thermostat is not going to
make it stop doing that. It's only going to give you a little lower temperature as
a starting point.

Just make sure your existing thermostat is capable of opening fully. Put it in a
pan of water and heat it up. The rated temperature on a thermostat is the point
at which it will begin to open. Continue to heat the water. By the time it's boiling,
the thermostat should be wide open.

The Stant replacement thermostats they sell at McParts are pretty much junk
any more. Either use a genuine Motorcraft, or one of these (http://www.partsamerica.com/productdetail.aspx?MfrCode=MRG&MfrPartNumber=4365) (actually made by
Robertshaw).

If the thermostat checks out OK, what's likely happening is your lower radiator
hose is collapsing. Many aftermarket hoses have eliminated the spring inside,
but you can buy one separately if yours doesn't have one. A partially clogged
radiator can also make the lower hose want to collapse.

[Ltngdrvr]

As far as the coolant mix goes, water is a better coolant than anti-freeze so a mixture that is more water, less anti-freeze will cool better while still protecting the metals in the motor from corrosion. This sort of mix will raise the freezing point though so if you live someplace where in winter it gets really far below freezing then you would want to add more anti-freeze.

The role of anti-freeze in warm weather is to protect the metals in the motor from corrosion and to raise the boling point of the mixture, it DOESN'T make the cooling system cool better.

[JamesD]

Make sure your fan clutch is working properly.

James

[Whtstang]

When an engine runs hotter at higher speeds, it's often a symptom of a coolant flow problem. Commonly a clogged radiator. When you worked on the cooling system, what kind of service was done to radiator?

[85GT-79FJ40]

Your not really overheating but putting in a lower temp thermostat really wouldn't change the situation at all. No matter what temp thermostat you have when it's fully open it's flowing as much as it can. A lower temp thermostat just opens faster. Typically if you are having trouble with overheating at speed it's your radiator. A collapsed hose like mentioned earlier would certainly be a big problem too. But my crapco aftermarket lower hose is slightly kinked and i've never had an issue. But I also have an aftermarket aluminum radiator.

[haromaster87]

Well, i've gotten on it since then and it didn't heat up. I think the fact that I had been in traffic has somethin to do with it.