I thought my car was running hot due to a bad thermostat. So I bought a Stant brand. I took out the old one (which I found out was a 195) and replaced it with the new one (also 195). It now runs even hotter more often. wtf?
i'm going to install the old one back. Its only 3 months old anyways. I just thought it may have been a cheapo. but it turns out the one I bought is. And I thought "stants" were one of the best.
I still run hot on idle. past 220. This is getting old.
I m reqdy to run this car into the river and leave it there.

 

My 89 has always run hot at idle after reaching operating temp. As long as car is moving and air dam is in place no problems. My fan does not kick in until 230, this use to scace me. But after putting over two hundred thousand miles on it I have gotten use to it. When I first got car put new waterpump on had radiator changed(fan turn on temp scared radiator guy), tried cooler and hotter stats to no advantage. Replaced relays too. Car still does the same thing have to idle at a light in summer and she climbs on up there. Of course running the ac kicks fan in and have never gone above 220 with ac running. Except when fan goes bad. Big old plastic fan wears out motors fast. Replace with liftime and change often. Been through three. If you have the one belt system also get liftime alt. as these go bad often also.

 

Mines a serpentine. (91Z28 350TPI)

I even had to wire my secondary fan to come on with the ignition just to keep it from boiling over. It runs at the 220 and just shy of the red mark with both fans on!!.
I even took out the radiator and cleaned any debri between it and the cooler. Air dam is good.
Flushed system. Its a new Motor as of Feb this year. New water pump. Only when we get 90 and above here in Texas does it do this. I take off down the road and she goes back down below 220. But if I get below 20mph or stopped, there she goes close to the red zone again.
And I have not even charged my A/C yet!!! What then?

As far as these fan motors...do they have a tendancy to "slow down" speed as they go out, or do they go out all together? Could It be one or both is not spinning fast enough? Is there another type of radiator to use, more heavy duty? Better cooling? Any Mods for such an issue of cooling the system?
I would even do a Mod for improvement . Summer here is just beginning and I,m about to get my A/C repaired but too afraid to.

 

220° is NOT overheating. That's so far below the boiling point of coolant, it's just barely warm.

The factory fan switch in single-fan cars DOESN'T EVEN TURN ON until about 235°!!! In other words, the factory's opinion is, the motor DOES NOT NEED COOLING until 235°. Now granted, I'm not suggesting that the factory knows anything about their cars, or anything radical like that; but still.

Which means, "overheating" CANNOT POSSIBLY occur until some temp well above 235°.

Really, it doesn't sound to me like you have a "problem" at all, except possibly a bad radiator cap.

Maybe you want your motor to run cold for some reason, that's a whole different matter. You'll NEVER get it to do anything except what I described, which is the stock operation, by just replacing stock parts with stock parts.

Yes I used to live in the deep South myself, for many many years. About 35 I guess. In fact I still have one brother living in Alabama. So I know about driving in the heat and how cars are supposed to behave. I ALWAYS used my AC; when I lived in Tennessee and Mississippi, I ran it continuously about 6 months out of the year, and part-time another 3. I've had one of these cars since I believe it was 1985, so I'm pretty familiar with how they work in general.

If your car "boils over" at the red line, which is about 240° (just barely above fan turn-on), you have some other problem; not enough antifreeze (should be 70-30 water to AF), bad radiator cap (should hold about 16 or 17 psi), leaky cooling system, etc. The boiling point of the correct coolant mixture at normal operating pressure is somewhere around 260-265°.

 

I forgot you had the two fan setup, so I'm not sure. My one fan system will start slowing down. When I first got car worried the hell out of me. Don't drive it much now needs tranny but after 289,000 miles I guess I could expect that. And like sofa said if it ain't boiling I would not worry about it.

 

I, of course, was guessing at my numbers. 220 being the midpoint.

and yes, it reaches 240 (if thats right at the red line) on idle at stop signs. And she has boiled over on me a couple times if I sit too long. and thats with no a/c yet.

I'm going to put my old thermo back in this weekend, it didnt run so hot before I put the new one in (same temp thermostat). Go figure.
But it did approach the red line at long idles. Depending on the weather. Now that we are in the 90's and soon to be 100's. I'm concerned, especially with me soon to get my a/c working.

Maybe I should consider Montana?

 

The thermostat won't really have much to do with how hot the motor gets sitting still; mostly it will control how cool it gets driving down the road.

I'd be inclined to think that you have some other issue, that the timing of it just coincides approximately with changing the thermostat. I don't think messing with that will do any thing at all about any "boiling over".

The red line on the gauge is somewhere around 240°; the middle line is around 210°, all just kind of rough averages of course. It's not a precision instrument or anything like that. But that's a crude approximation anyway. In any case, "approaching the red" isn't the footsteps of doom. It's pretty much normal.

The boiling point of a proper water/AF mixture at atmospheric pressure is about 230°. If your car boils over anywhere below the red line, then either the rad cap isn't holding pressure (pressure increases the boiling point substantially) or you don't have the right mixture of coolant. Too much AF makes the coolant less efficient, because AF doesn't hold as much heat as water (its specific heat, the quantity of heat energy required to raise a unit mass of it by some unit temp, is much lower than that of water, so much less heat energy will raise its temp by many more degrees than water). On the other hand, if you have too little AF, the boiling point will be too low. You want no more than 50/50 AF, and ideally about 30% AF.

You may also find that your water pump isn't working as well as it could. Obviously if the water doesn't circulate enough, it will get too hot while it's in the motor, even if the radiator and fan and all that manages to cool it all the way down to ambient. You should be able to see coolant vigorously shooting out of the vanes when you take off the rad cap (once you get the boiling over situation cured of course...)

Yes the fan motors definitely do go bad, and they definitely can run slow when they get old. A fan motor is dirt cheap, so that's something you could try just parts-swapping, it not being too painful.

You can also try some Red Line Water Wetter in your coolant, that stuff makes the water "wet" the castings better, i.e. it improves the heat conductivity from castings to coolant and coolant to radiator.

 

Ok thanx guys for all the info. Even printed it all out to take home so i dont forget.
As far as this red line water wetter...where can I get it and do the local parts stores sell the fan motors? and is there a particular brand to keep in mind? I'm taking all roads here to insure a "safe" temp on my motor with summer bearing down.

 

You can reprogram the ECM to turn the fan at a lower temp along with a 180°F stat (wouldn't go much lower than that.) Won't do much good to do one without the other.
I've heard that GM kept the temp high on these cars to lower emissions, I think that's why the EGR was added; to lower the actual in cylinder temps for lower NOx and not affect performance too much.

The radiator also cools the tranny oil, so kept that in mind when you're chasing a cooling problem.

 

I run a 160 thermo w/cool fan switch and a external tranny cooler.
I can run the car in traffic with the ac on in mid summer with no problems, yet.

 

I believe Vato Zone has the Water Wetter, at least they used to anyway. Comes in a little bottle that holds about 4 to 6 ounces.

Couldn't say about the fan motors; at different times I've used a GM one (broke while I was on the road about 500 miles from home), and I think a NAPA one once. Seems like one from any of the REAL parts store A/C service brands (Murray, 4 Seasons, etc.) would be better than the Vato Zone type of thing, but I have no proof.

If you REALLY want to hook yourself up with a fan, the hot ticket (cold ticket?) these days is the one out of a Taurus or Sable or Linclon with the larger 6-cyl; 3.8L I think it is. Get the whole fan assembly, either a junk one or a new one. Those things move some SERIOUS air.

 

...and of course the cheap thing, first thing i'd do, if it's boiling over that early, is throw on a new rad cap. something like $10 right?

 

So any year?
You saying do away with the dual setup or are these fans the same diameter as my duals.? Or are you saying just use the motors. Just clarifying.

 

Oops, I forgot you had the dual fan.... in that case, I think it's the one for the smaller 6-cyl; that one is a dual that moves about the same amount of air total. It's about a 96 model IIRC. If you get a junk one, get the last foot or so of the wiring, with the connectors.