Thermostats & All That

Hi to all

I note that I can get thermostats in the following ranges: 160, 180 & 195.

Modern wisdom states: Engines burn fuel more cleanly and efficiently at higher temperatures. With the coolant at 195 degrees (instead of the more traditional 170-180 degrees), for instance, you'll get better performance, less pollution overall, and greater fuel economy. And while 25 years ago, using a 195-degree thermostat might have shortened the life of the engine, oils have gotten much better over the years. Now they perform much better in extreme heat, and give the engine plenty of protection in those temperatures without breaking down.

So what is the latest take on this forum with respect to oldies from the 50's & even earlier?

Thanks

Johan

I have always believed a cooler engine runs better & lasts longer.I also have used Quaker State 10W 30 year around for 30 or more years & buy it on sale.With my 25 Buicks & abount one million miles,never an oil related problem except a 67 that had worn down cam lobes when I got it.Buick engineers believed at first that fuel injection worked better at higher temps but I think engines last longer today beceause of much better oil.While I,m on the subject,My owners manuals all say change oil at about 7500 miles,but the GM dealers say 3000. Guess why.We could save 3000000 barrels a day but who cares.Gas in Flint is well over 3.00 now.

What the manual doesnt tell you is that is the max. miles allowed with the min. maintiance and still protect your warrentee.Take better care of your car it will take better care of you.

I like the 180 or 195 degree stats as the heater works better.

@ Norb - I agree about better quality oil 1000% & hence better engine protection, but your indirect evidence doesn't quantify the fact that 190+ thermostats is now the norm... Is it a direct correlation with better oil????

@ Ron - Now there is a GOOD reason to go wth the higher value (all other things aside). I kinda live in the frozen wastelands and heat heat heat is a good thing!

Thanks

Johan

Agree with the fact that oils are better today, even when they weren't if you changed oil and filter regularly an engine would last well over 100,000. In our climate when it gets hot I'd rather have my engine running as cool as possible, as in my case the gasoline is a problem and when she gets a little too hot I have even experienced vapor lock. Engines last longer these days cause they don't have to work so hard too. Traveling at 60 mph the tach reads about 2000-2500 on the newer cars. I don't have a tach on the old girl but around 60 shes working.

@ BRH - If I'm understanding you correct then, it may be beneficial to have 2 temperature thermostats. One for the anticipated city driving, and short trips that can use a higher value, say the 190, and a second which I change to when I will be doing a long distance trip like Vancouver or so, using a 160...

I can also testify to vapour lock (or what I think it is). In my case the car would NEVER immediately start again after the engine is hot & was switched off. I had to wait anywhere from 10-20 minutes because I could literally hear the boiling in the carb. Once cooled down it would fire up first time!

All three of my Buicks have well over 100,000 miles with good heat in zero & below in mich . However,The Park Ave has 137,000 Mi. with the origional anti freeze and thermostat & still very good on oil. It,s a 99

Well if ya wanted to go through changing thermostats I would have the higher temp one in for highway (190). And the lower one (160) for city. Reason being on the highway plenty of air is going through the radiator to keep her cool on the highway, especially the way I drive.

The thing about thermostats is that they only set the <span style="font-style: italic">minimum</span> temperature at which the engine will operate. If your cooling system can't pull out enough heat, a 160 thermostat will do nothing but stay open all the time. The car will simply run at whatever temperature the cooling system can manage to extract.

In every car I've ever owned or built, including race cars, I used either a 180 or ~195 without problems. My Mustang currently runs a 192 thermostat with a giant radiator and stays rock-steady at that temperature even after 20 all-out race laps. People like to see nice, cool temperature gauges, but that's not necessarily the best way to run the engine. Remember that you want the top end hot and the bottom end cool--hard to do without an oil cooler, so compromise on the thermostat for best efficiency.

The simplest rule of thumb is this: if it isn't blowing steam, it isn't running too hot. If it keeps its cool at 195, then you're not having a cooling problem. On an older car, perhaps a 180 will give you a measure of comfort because of the inefficiencies of our old cooling systems, say, for going up a long hill. You'll have some reserve to handle the load without overheating. I'm going to run a 180 in the Buick for this reason--that straight-8 is notorious for running hot, especially the rear cylinders, and coolant doesn't circulate very fast back there. Those extra 15 degrees might give me a cushion when I'm pushing it hard.

Does this confuse the issue?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr. Solutions</div><div class="ubbcode-body">I can also testify to vapour lock (or what I think it is). In my case the car would NEVER immediately start again after the engine is hot & was switched off. I had to wait anywhere from 10-20 minutes because I could literally hear the boiling in the carb. Once cooled down it would fire up first time!

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A cooler thermostat probably won't help this. When a car is sitting, the cooling system is shut off and you get what is known as heat soak. The hot exhaust manifolds and block are heating your fuel, not the cooling system. When the coolant stops circulating through the radiator, all that heat has nowhwere to go but to radiate from the cast iron like a steam radiator in your house. Even if the cooling system is running 15 degrees cooler with a 180, that 15 degrees is insignificant compared to the heat retained in the block and heads that now has nowhere to go. Remember that the temperature gauge on your dash only tells you <span style="font-style: italic">coolant</span> temp, not actual engine temp, which is at least 100+ degrees hotter.<span style="font-style: italic">That's</span> what is causing your problem with "vapor lock". As soon as you get the cooling system working again when you start the engine, it cools off quickly. But if it won't start, all you can do is wait for it to cool off on its own. Airflow, as with the radiators in your house, will greatly accelerate the cooling process. Opening the hood will help a great deal.

My new Audi allroad wagon has a twin-turbo engine with an after-run pump that circulates coolant through the turbos for 5-8 minutes after I shut it off. It also runs the cooling fan on low speed to keep airflow through the radiator so the coolant doesn't just get heat soaked too. Pretty cool and it will greatly extend the life of the oil and the turbos. You can hear it running as you walk away.

I would stick with 160 or 180. Many of our older Buicks, my 55's included read HOT on the temp gauge at 200*. Even with no problems I don't looking at the needle way up there. Also if using 195 you should have at least 50% coolant mixture and a 16# cap (which would require replacing or modifying the filler neck). An engine would tolerate those pressures but maybe not the original radiator or heater. The reason for the 50% and 16# is that any engine and more especially a nailhead and some others will have hot spots much hotter than the coolant temp. I tried a 195 years ago in one of my 55's and before the thermostat opened I started getting that sick chugging percolator sound before it puked coolant (less than 50% mixture) out of my 6# radiator cap.

Back in the late 60's the family had a 55 Special (with a 160) when we lived for a year in the UP of Michigan. Never had any problems with enough heat in the car.

Willie

The temperature of the transmission fluid is dependant on the engine temperature. So, if you are running a 195 the tranny will be running hotter than a 180. The cooler the tranny runs the better off it is.