True about a massive failure. Let me restate that as "cooling problem". But most of us seem to forget that the purpose of the thermostat is to limit how cold the truck operates. So if the engineers thought it would be fine to cruise along at 180 -185, then great. When you need some extra cooling, like hauling a boat in the mountains, nice to have some extra capacity. I don't accept that the normal operating temp of a truck is always going to be wide open thermostat temp + 5-10 degrees. The engineers gave the thermostat control until 212. Then they throw electric fan cooling at it to get back below wide open stat temp and restore control to the system loop. The engineers designed it that way because they don't want it at 215, 217, 221, 227, etc. And if you are hiting these temps at 50 mph you have other problems. The idea that every aluminum engine needs to run at 205+ is also not true, plenty of 180 stat imports out there. I've got a 23 mpg Kia minivan with 215,000 one owner miles, 180F from the factory, that lower temp did not kill mpg or increase engine wear.

But, to each his own. Those in the frozen north need more heat in the winter. Those in hotter places may want cooler temps. People seem to be as excited about engine temp as they are about the best oil. If we knew our oil pressure we would be worried. If we see the temps in digital form, we worry for a while. I'm happy mine is not jumping up to 227F. Maybe I have a warped head, and running a lower temp does not allow the aluminum to reach that condition where it lets the gasket leak.

 

Forgot to mention the analogy of the thermostat and the throttle. Both are a valve, and open from a minimum to a maximum position. But you don't normally spend a lot of time at wide open throttle. The thermostat is not on/off like a light switch, or an old style home thermostat. Pop one in a pan of water (pan approved by SWMBO) and bring it up to a boil. See pix 1. You'll see it slowly opens, and slowly closes, not a snap action. If you are at the low end of the range of temp for the stat, say 180 - 195, it may close as cooler water comes by, then open back up. Once you get to fully open condition for the stat, it can still close, but usually by then (on a warm day) the rest of the cooling system has warmed up, and it won't shut 100%. So the unit can "control" the temperature and keep it (a) above the minimum operating temp - when it first begins to open; and (b) keep it within a narrow range and stable temperature is a good thing for stuff that expands and contracts. Once you reach the point where the stat is 100% open, and staying there, it is like having no stat at all. So IMHO, you want normal operation in the minimum opening temp to fully open temp, which on a D2 is 180 - 204F. Not like in the pix 2.

 

That picture 2 does show a kind of high temperature, but if you had a picture of the car's temp monitor, it would still be showing dead center normal. So the engineers feel that temperature is perfectly normal for the vehicle, just not optimal when looking at the temps required to start the electric fan, unless that gauge is on a TD5 engine.

 

The same engineers planned the alarm system, and the lack of an oil pressure gauge. That's my point, you are lulled into a feeling of safety with the D2 pulse width modulated gauge, which is designed to show guage level from "X" to "Y" degrees F, and once it starts to move above that spot, you have already gone into the range that most people would consider too hot. So you let it go more, thinking it is just a little warm. It's not a linear gauge, it is an idiot light with a pointer. On old detroit iron, we got used to the guage at a certain point. If it began to ease up, we picked up on it. On a D2, once it rises, it is well past the point where you should have looked into it.

BTW, Rock Auto and Orielly parts sites show a 63 Buick Skylark 215 OE temp stat as 180F, with alternate temps of 160 or 195. Maybe I'll try that 160 for summer....

And if you consider "normal" to be anything less than boil over; a 50:50 mix of water and antifreeze will boil at 227 F. Add 14 PSI pressure cap and that is up to 263 F. The Rover 18 PSI cap takes that a bit higher. But no one wants to run near the bleeding edge. Maybe a little less heat would mean a little less pressure on the head gaskets. You do need that sort of capacity to take care of hot spots and eddy currents within the cooling system, steam pockets don't cool very well (the reason for Water Wetter and Purple Ice to improve things, they reduce the size of the bubbles). Water wetter and purple ice plus distilled water will out cool 50:50 antifreeze mix, but that would be summer only, and no corrosion protection. But we can't get people to change coolant every two years now, or even their tranny fluid every 3 years or so, but the same ones will rage on about Amzoil synthetic barbque sauce in the bottle with the gold stripe as being the only oil or your engine will melt.

It takes reasonable maintenance of all the systems, not just the bare minimum for long life of a vehicle.

 

I understand your point, but until manufacturers start providing real-time numeric thermostats, it's all the average person has to go on.

 

Ultra Gauge for president!

 

It has already saved me a ton of money by letting me know my thermostat was on it's way out.