Rickman48

I read quite a bit, recently, especially during this 'heat wave' about a lot of people having heat related issues.
Having had a personal expierence that changed the whole performance/economy aspect of my car, I thought I'd relate the situation.
First, I'm from the generation where we'd flush the radiator twice a year, and change the thermostat at the same time - cheap insurance.
180 for the winter, 160 for the summer.
This all went away in 1975, when catalitic converters became mandatory!
To make them 'effective' on short trips, the manufactuers deceided to go to the 195 - engine longevity be damned, as IMO, heat is a killer!
To make it worse, no such thing as 'dual' cats, and exhaust - more heat retention - more heat-related failures!
The only new car that I bought was a '86 Grand Prix 2+2, and it had the 'corporate' G-code 305 that was getting 10-12 mpg, even with the 'performance' 3:08 Posi, and there was no performance!
At about 18k miles, the thermostat stuck, just as I was getting home.
Heard it 'perculating' when I shut it off in the garage - turned the key on, and the guage was pegged! Figured I'd change it in the morning after it cooled-off, and went in the house.
Next day, looked for a thermostat and gasket in the toolbox, found a 180 - but that's all I had. Installed it, re-filled the radiator, and went for a ride to make sure I hadn't hurt anything else when it got that hot.
To my surprise, it changed the whole 'personality' of the car - way more responsive, actually performed 10+% better, and the gas mileage went to about 15MPG.
Since I was due for the EPA sniffer test, I figured if I failed, I'd just put a 195 back in, but it passed with about 20% better than average!
I also had a dealer appointment in a couple weeks, I figured I'd cover all my bases, and ask about voiding my warantee when I got there.
Service writer didn't know. but the zone rep happened to be there, didn't know, but called the factory - who told them it'd only affect the polution control part of the warrantee, and explained the 'short trip' reasoning.
Put 220k miles on that car - 1 water pump, 1 timing chain, and 3 CCC carbs - went to a 700 trans @ 130k - another driveabality improvement!
Got a 180 in my '91 'burban right now - no overheating issues with 186k.

Just thought I'd mention - worked for me!

ah64pilot

There is another school of thought that a 180 vs a 160 keeps the water in the radiator longer and allows it to cool better. However, if you think about the operating temp with either thermostat...when does the thermostat ever "close" after the engine is warmed up. To me, the theory that it keeps the water in the radiator longer is bogus. It just seems that it would raise the average temp 20 degrees by using the 180 over a 160.

I use a 160 here in Texas, no matter what the season. I like to look down and see 175 on the gauge rather than 195. And yes, the car does run better with the lower thermostat. It also helps combat heat soak detonation in higher compression engines. Better all around in my book

Rickman48

Well, up here in the 'snow belt' we have to keep the women warm in the winter!
I could live with a 160 all year around, with earplugs!

ah64pilot

Eh, mine can suffer And I don't need earplugs because I can't hear her over the exhaust anyway lol!

Intragration

Nice! The old loud-exhaust wife-unit mute trick!

I run a 195, I've never had problems, I always figured it was better to get the engine thoroughly warmed up as quickly as possible. I've gone under the assumption that it helps with fuel atomization and also eliminating moisture in the crankcase. Is there any evidence that running a 195 instead of a lower temperature thermostat contributes to premature wear? Not arguing, just asking, I'm open to the idea.

stevengerard

I got rid of mine for years after multiple stuck failures. I now have a 180 in there and did enjoy the heat on cold spring nights with the top down. But heat sink with the starter went even higher, so now i have a new high torque starter

RetroRanger

I saw a post recently where Mark EFICutlass stated some places dyno engines w a low water temp (110°?) to show more power than real world 160-180° water temps

wmachine

Well, somewhat correct. A thermostat keeps a minimum temperature, not maximum temp or even an operating temp *as long as* the operating temp in above the thermostat temp. Think about it.

There are a lot of variables with the thermal dynamics of engine cooling. And once you start to deviate from stock, you can end up in a lot of hot water. (Sorry, couldn't resist). It needs to be a balanced system. I'm not an expert in balancing the system, but I do know you have to consider the whole system, not just one component.
For instance there is such a thing as pushing the coolant thru the system too fast. Doubly bad, because it can't pick up the heat and can't properly dissipate it in the radiator. (And that means that running without a thermostat can cause overheating, which puzzles many)
Generally speaking, all *totally stock* Olds cooling systems (including grills shrouds, hood, etc.) including all the high performance versions, have adequate cooling systems. So that makes a good starting point.

oldcutlass

Which generation flushed a radiator twice a year?

Basically an engine has an operating temp when it's fully warmed up. There are many variables tune, airflow, outside ambient temp, water flow, amount of coolant, any other additives, etc... the thermostat is there to set min operating temp not maximum. The difference between a 160* and a 180* is the amount of time it takes for the temp to get to it's minimum operating temp. With the intro of the 195* in later model cars, it was to raise the operating temp to maximize atomization and prevent the catalytic converters from carboning up.

Idealy with the older cars, the thermostat was mainly there to speed up the process to get to a minumum operating temp, and to provide heat in the winter. Our cars like an operating temp of 170*-190*. Lower operating temps of below 160* cause premature wear and poor performance.

There are alot of threads on other sites to get engines to run cooler, using a 160* thermo and drill 2ea 3/16 bypass holes in it, quality clutch fan, 4 row radiator and shroud.

TripDeuces

My two cents:
I have a friend who had a race only car (not Olds) that would constantly overheat. We couldn't figure it out UNTIL he told me he had no thermostat in it. Since we didn't have a correct thermostat handy and were in a time crunch I knocked out the guts of an old thermostat and just installed the outer ring with the ~1 1/8 hole in it. Voila, instant temperature drop and no more overheating.
I do think that somehow the restriction helps the water cool as it passes through the radiator. As evidenced by the above story that seems to be the case. But here's the rub. On an Olds engine (also BBC and probably others) there is a water bypass that constantly allows water to circulate albeit at a lower rate than just an open hole. When thermostat opens you have less of a restriction and more flow. It could be that it is still enough of a restriction to allow the water to cool sufficiently as it passes through the radiator. This makes sense.
Also, as WMachine stated, the thermostat only begins to open at the stated temperature. It is the minimum temperature that it starts to work. It is not maximum temperature or operating temperature in anyway. That is dictated by the engine operation and radiator size and efficiency of the cooling system overall. If you're having trouble with overheating I would be looking at the cooling system as a whole

Rickman48

Part of my intention was to point out that when you ask for a thermostat at any auto parts store, the kids automatically give you a 195 - they never ask!
One of the 1st things recommended on a GN was to change to a 180 - 160 for even more power!
Same with adding a computer re-programmer or chip in the '80's.
Really wakes up a LT-1!

archeryshooter

I agree But also if your motor gets hot at low speed you need more airflow if it gets hot at highway speed it may need more coolant flow

Intragration

LT1s and 3.8 turbos are each somewhat unique situations. The LT1 had a cooling issue that required a reverse flow system, and the 3.8 turbo in effect multiplies the advantage of a cooler intake charge (not to mention that turbocharging naturally increases intake charge temp) thus the intercooler. I'm not saying that an Olds motor wouldn't benefit from cooler running temperatures or a cooler intake charge, just that those two motors in particular have their own specific cooling issues.

As Wmachine alluded to, anytime you're running OVER 195 degrees, such as on a hot day, in traffic, etc., there's basically no difference between a 195, a 180 or a 160. The engine is then running hot enough that all of them would be fully open. If your cooling system and driving situation keeps the temperature right at the rating of your thermostat, then a lower temperature thermostat might give you a buffer, but once your driving situation causes the temperature to reach the thermostat rating or higher, then the rating of your thermostat has nothing to do with seeing higher temperatures. At that point, a radiator with a higher cooling capacity would be the answer.

oldcutlass

Exactly!^^^^^^^^^^

J-(Chicago)

Words to live by.
I run a 160 thermostat with a 1/4" hole drilled into the outer ring. Also a 4 row radiator from an 80's dually 454 truck and 2 electric fans. If it goes over 175 in 100 degree heat, something is wrong.

ah64pilot

I love threads like these...where the experienced guys come out of the woodwork and chime in and it turns into a civilized discussion and brainstorming session. This is exactly the type of thread that makes me proud to be a member of CO. And it's about thermostats! lol!

allyolds68

SBC boat motors typically run with 140's or 160's. There's an unlimited source of cool water with no radiator issues (in a raw water cooled boat) so there must be a reason.....

I thought I had an overheating issue in my boat this spring and I chased it to the tune of $300 until I bought an IR thermometer to find out that I was running at 160 & I probably have a bad sending unit. The problem with running no thermostat (on a boat anyway) is it masks the problem that's causing the overheating. The same would be true of a car that had an adequate radiator

rustyroger

Modern engines are built to closer tolerances than older ones, an overcooled engine has in effect tighter bore clearances because the cylinder walls don't expand to their required amount.
A properly cared for modern engine will be good for 200+k miles so I don't buy the cooler engines last longer theory, an accurate dyno will tell you if cooler = more power.
The pistons warm up quicker than the bores from a cold start, that is why tolerances are built into any engine, as the engine gets to operating temperature everything comes to designed operating tolerance, a good reason not to nail the throttle on a cold engine, let everything get to operating temperature first.
Taking the thermostat out altogether makes warming up a very slow processs, and indeed may not allow the coolant to stay in the radiator long enough to cool properly.
Race engines often have a restrictor in place of the thermostat (essentially a hole the size of the thermostat opening), but such engines are normally for race only use and a potential fail item (the thermostat) has been removed from the system. However such cars will have been warmed up before they go to the start line.

I used to look after a fleet of diesel powered Renault vans, the owner would not be told running with no thermostat was a bad idea, a frequent problem was pistons partially seizing in the bores. He also thought jamming the oil pressure relief valve to increase pressure was a smart idea, even after blowing oil filters because they couldn't handle 110lbs pressure!.
I told him to take his business elsewhere after a short while.

Roger.

oddball

The bypass goes back into the engine - not out through the rad. This is to prevent cavitation, as auto water pumps can't push against a full closed system.
The only bypass that goes out to the rad - at least in every stock configuration that I'm aware of - is the jiggle valve in the thermostat. Definitely not a high flow application.
Some setups had the return from the heater go to the rad, others went back into the engine. Neither case is a bypass for cooling.

Rickman48

I agree -no thermostat is a bad idea - been there, too.
My 1st car ended up with a sbc 301 - a 283 bored .125, with 12 1/2 J+E pistons! [good fuel, back then!]
Tried it - more o/heat than with a 160, but was told with cyl. walls that thin, with that compression, not much would help!
Even had a 7-blade fan - sounded like a truck - but it was a '56 and there wasn't much more you could do.

stevengerard

and to clarify I had a restrictor in place instead of a thermostat. but the car runs much better now with the 180 in it

70olds455

The LT1 engines in the 4th generation camaros have the reverse flow cooling which was designed for cooler engine temperatures than the standard SBC engine. These engines came with 10.5.1 compression. The common problem with these cars is that the fans were programed to come on at a higher engine temperature for emissions. I know this because I have a 95 camaro Z28 and the temperature gauge has gone to the 3/4 mark before idling in traffic in hot weather. On highway driving it stays around 180 degrees however.

Intragration

It wasn't just so that it would run cooler, it was because specifically there was a problem with the heads or cylinders running too hot, so the reverse flow was intended to cool them first, with coolant right out of the radiator. I bought a '96 SS new, and I remember reading about this at the time.

Rickman48

Integration - you should've read a little further - Chevy was trying to cool the heads first to obtian a performance increase - there was no problem! Cooler intake charge!
Worked pretty good - and then the LS series appeared. The rest is history.

ah64pilot

LT engines are great! I wish they would've kept developing that engine instead of scrapping it for the LS...although they are both good. But the LT torque curve started so low and it was flat as hell!

oldcutlass

I bought my first New Vette in 92 with the LT1! It was a cool car lots of power, and got 28 mpg!

ah64pilot

I loved the 6 speed / LT1 combo...90 MPH on the freeway, 1800 RPM and 25+ MPG...that car was the best.

On Christmas day 2002 I did a run from Austin to Houston (190 miles) at midnight...it took me 1:30 city limit to city limit...we AVERAGED about 120-125 mph. Man, to be young again. I loved that car! I wish my wife had never traded it in on a truck while I was away in flight school

70olds455

Not only do the LT1 engines get great gas mileage but they are low 14 second cars in stock form. With a few bolt ons they will run high 13s in the 1/4 mile.

oldcutlass

Sigh, I traded mine for my son! My wife was not supposed to be able to have kids... It was'nt 3 weeks after I bought the Vette, I was sitting at the breakfast table reading the paper and she threw one of those home pregnancy sticks on the table. Now mind you, we lived 30 mins in the middle of nowhere. I made her go out and buy 3 more kits - different brands! NO LUCK, she was definately nesting!

ah64pilot

I beg to differ! My '96 Formula WS6 - 6 speed went 13.50's bone stock! And that's what happened to me. She got preggers and didn't wanna fight a car seat in the WS6, such a sad day I still wonder whether the trade was worth it or not lol! J/K!