I know this sounds ignorant (and there are many variables) but what would be a “normal” or acceptable water temp running at 70 mph at an outside air temp of 85-90 degrees? I’m running a 180 degree thermostat and I’m showing between 192 and 200 degrees. (With The AC on it kicks it up around 3 degrees). It gets hotter at stop lights (approaching boiling if it a real long light and hot outside) which I’m able to bring it down by putting it into neutral and increasing the rpm a little. Is all of this normal or indicative of a weak cooling system.
That's a pretty normal temperature. With 50/50 antifreeze mix, you're at 223 degrees for a boiling point. With a good working pressurized system, boiling is up around 250 degrees.
Yes, it helps thanks. Just trying to figure out if running above the thermostat temp is normal for these motors.
There's a lot of factors that determine engine temperature. A lower temperature thermostat
might drop the engine temp a little, but when really all it does is let the coolant run through your engine a little sooner. Most of the time, it isn't going to affect the engine temperature. You could switch to a 160 and see what happens. Might help, might not.
There's a ton of other factors though. A lean carb can cause high temps, so can engine timing. Things like the "splash guards" under the car help channel the air through the radiator and they are often missing in older cars. The spring that's often missing in the lower hose (keeps it from collapsing) is another factor. I know you said you've replaced the fan clutch and that's good, but they aren't all the same. The Hayden 2747 clutch has been my weapon of choice with better results than the Advance Auto supplied version I tried first. You haven't said anything about a fan shroud either, and I would expect an A/C equipped car to have a fan shroud.
One other factor that guys never think about is the accuracy of the temperature gauge. It doesn't matter what type or brand, the truth is that they can be reading incorrectly.
It comes down to the fact that your car is really running about normal temperatures and you could just leave it alone and be fine. As was said, if you didn't have the gauge, you'd be blissfully ignorant of the engine temperature.
Thanks John. I never heard of using CLR in a cooling system before. Can we be reasonably certain that the CLR will not react in some nefarious way under heat and pressure? Is this similar to what is used when they “boil” out a radiator?
This is just a bad idea. I've seen it done with cars that are having problems and that's great. Doing it with a car that's not? No... Just no.
Any kind of coolant flush, and it doesn't matter what kind, is tough on the components. As stated above, CLR shouldn't be used on copper or aluminum. All the engine flushes are going to clean out the crud, but at what expense? I've seen where suddenly heater cores and soft plugs start leaking after flushes. Maybe they would eventually, but why make things worse now.
Again, your car is really running about normal. If you want, look at some of the things I mentioned (like the "splash shields" for example) and fine tune on those.
You could just leave it alone too, especially if you aren't having any real overheating issues.