Shooter_Jay, I completely agree with your statement that "if your cooling fans and radiator work right, the 195 works just fine." But, if your engine never got up to operating temperature with the 180, then I'd say it was a bad thermostat. Let me tell you how I look at thermostats...
[ Shooter_Jay ]
I wasn't convinced either way but it definitely ran cooler with the 180. What convinced me was running the koer test. Everywhere including the ford oem info says run it at 2k rpm for two minutes to get up to operating temp then shut off for 10 seconds then hookup then run koer. With my 180 it was never warmed up so it was tough to trust the codes. Put a new 195 in and the gauge is now out of the cold area right at two minutes in nice weather. Also I think temp gauge is a real gauge, not like the oil pressure which is like a 4 position idiot needle or something, correct me if I'm wrong.
I think your close, but logically, when the coolant gets up to 180 it kicks into the mode that cools it much more efficiently. My 195 will get to 195 much faster than my 180 is what I'm trying to say. If it was designed to run from 190-220, then you are running it under operating temp for longer. That's all I'm saying. Of course, maybe it's worth the trade-off because you're ambient temperature under the hood will be a little lower with the 180 I think.
Also I think they would have designed it to warm up until 5 or 7 degrees above minimum operating temperature before the t-stat opens. That's what I would have to do I think with my perspective as a machine designer.//
jpetillo said:
Thermostats should all stay closed when the engine is within maybe 5-7 degrees of the rating, then be wide open when they are about the same amount above the rating. I'd say the result is that you should have seen about a 15-degree drop in engine temperature under the same conditions with the 180 as you would with the 195. Maybe the temp gauge isn't so linear, though, and could have fooled you.
The engine should have warmed up at about the same rate with either, since they will both stay shut when under 170 degrees.
[Shooter_Jay ]
the 180 will start opening 15 degrees earlier than the 195 however you want to do the math.
jpetillo said:
Not that you said anything about this, but a cooler-rated thermostat will not keep an engine from running too hot, either. Both a 180 & 195 will be fully open above about 205 or so.
[ Shooter_Jay ]
and the 180 will be wide open to full coolant flow 15 degrees earlier than the 195 however you want to do the math.
jpetillo said:
My arguments about choosing the temperature value is that the manufacturers want the engine to run at a certain temperature. Running cooler or hotter isnt right, unless you know more than the engineers who designed it.
[ Shooter_Jay ]
yes, or unless you are looking to push the envelope more than the engineers to gain performance but maybe wear stuff out a little quicker or not.
jpetillo said:
The ony reason to start playing with the thermostat value is to make up for something else not working right, which is what you mentioned - assuming that you're not racing the car, etc.
Let me know if you agree or not with what I said - they're just my thoughts.
Half of your points argued my case for me. Who is this, John F Kerry?