m05fastbackGT

Is the stock thermostat rated at 180 or 197 ?

My concern is..I was led to believe, the stock stat for the GT.. is rated at 180 While the stock stat for the V-6, is rated at 197..

However.. Doug from Bamachips has stated, that most Ford factory thermostats are rated at 197


Anyway..if anyone can help clear this up, I'd really appreciate it..

Thanks

70MACH1OWNER

Hey Rocky,
I really don't know the answer to your question but I have the Aeroforce scan gauges and my coolant temps run between 190-195 in hot weather of cold. For what it's worth.
Scott

GRAYPNY

Check this post~

http://forums.bradbarnett.net/showth...ht=hot+running

theedge67

You are 100% correct. 180 for the GT, 197 for the V6 is when the thermostat starts to open.

saud alzaabi

So If I am to change my thermostat ... What do u think Is the best ?

m05fastbackGT

Steve ! what is Doug referring to when regarding most Ford factory stats, as being rated at 197 You read the e-mail I posted right ?

m05fastbackGT

Scott, what I also don't understand is..If the coolant temps run between 190-195 in either hot or cold weather..Then what is the purpose behind lowering the fan temps, from the factory settings in the first place ? I really don't get it..How is running the fan at 196-193 going to cool down the coolant temps any further..

theedge67

The only thing I can think of is to make sure and keep the temps as cool as possible. Maybe the car won't make as much power over 200F??

dustindu4

The stock GT stat is 180, it is engraved right on it if you take it out. That's what mine said. If you run lower than 180 on a N/A stock engine, say goodbye to your cylinder walls

m05fastbackGT

I'm with you Dustin..I'm just trying to understand why Doug and other tuners, have the fan temp settings in their tunes...set lower than the stock program settings..

70MACH1OWNER

Dustin,
Can you expand on your statement? Not being a butt however can you explain? Because it take my engine 15 minutes to reach 180 degrees every morning. And why would a NA engine be worse than a SC'd or nitrous engine?
Scott

70MACH1OWNER

Again I don't know the answer to your question but according to Graypony when he put his stock tune back in his temps ran between 200-215. I for one think that is too high for something I want to last 150-200 K miles.
Scott

m05fastbackGT

I definitely agree Scott..200-215 is way too high, especially for an all aluminum engine..

But it also doesn't make any sense, to have the fans running at 195 and below either..

theedge67

Why would 200F be too hot for durability of an aluminum engine? For the engines of old, maybe yes. The reason is they were not designed to operate at those temps. They ran best around 160-180F. Obviously Ford knows what they are doing by setting the fans at 214-224F. If it were going to damage the engine, they would have set the fans lower.

m05fastbackGT

I understand where your coming from, but aren't cast iron engines more durable than aluminum ? And if so, then would not an aluminum engine run even better at cooler 190-205 temps

theedge67

I guess what I am saying is that excessive heat by itself does not damage an engine. It is 2 things caused by excessive heat that damages engines.

1) thermal expansion of parts causing tolerances to change. If the block is at 170F and the heads make it up to say...240, big problems, especially if the heads are aluminum and the block is iron. Different expansion rates of the metal will cause the heads to warp and/or crack. If the block and heads are both aluminum, and they are both 240, there won't be any warping because they will both expand the same.

2) coolant pressures are high at higher temps. When you start getting over boiling temps, pressure builds quickly and can blow out hoses, head gaskets, all kinds of stuff. The pressurized system keeps the coolant from boiling, but the pressure can be killer if it gets too high. How high is too high? Depends on the engine and how it was designed.

Bottom line is hotter running temperatures will not cause the engine to wear excessively as long as the entire engine is up to the same temps.

theedge67

You are right, it will make more power at lower temperatures. I think the stock fan settings are geared toward overall efficiency. A hotter engine will generally burn "cleaner" emissions wise.

metroplex

The 07 GT stock fan settings:
Low speed ON: 216F
Low speed OFF: 208
High speed ON: 228
High speed OFF: 224

The GT's stock t-stat starts to open at 175F-182F and is fully open at 202F. Sounds like a 180F t-stat to me.

Engines make the most power when operating at the optimal temperature. A colder denser aircharge creates more power since you are stuffing more oxygen into each combustion cycle. But the rotating parts and bearing surfaces have less friction when the engine and its lubricant are at operating temperatures (not when it is cooled down).

m05fastbackGT

I totally agree with everything your saying about the expansion rates being the same, providing that both the block and heads..are made from the same material..

However, what is preventing the heads from cracking/warpage in the V-6 ?

Being as the block is cast iron, and the heads are aluminum..Would not the different expansion rates of the metal, cause the heads to warp and crack

theedge67

It could, if the temperatures are very different between the two materials. That is why the coolant circulates and keeps everything close to the same temperature during the warm up phase. Aluminum tends to expand more than iron when heated. This difference is minor though, unless you get temps very high. The higher the temperature, the bigger the difference. At 215F, the difference between aluminum and iron isn't enough to cause problems. At 280+....it can be enough to start warping things...especially if the head is significantly hotter than the block. A cylinder head with no coolant circulating can get very hot very quick, and that is where you run into problems. Plus since iron is tougher to bend/crack/warp than aluminum, iron heads are more resilient to higher heat.

But as to the original question that spawned my rant...higher heat does not cause extra wear, or decreased engine life.