I highly disagree. The thermostat should only cycle a couple times while the car is warming up and then stay open. (depending on outside temp) The thermostat is there to keep the coolant from keeping the engine too cold in cold weather and to allow a faster warm-up. Reduced flow=Reduced cooling. Think of a clogged radiator.

I do agree that 180/185 is a more appropriate thermostat just for different reasons.

:cheers:

 

Here is an easy test to amke sure you are getting the prorper temp reading. You say you have 160 stat, well watch the temp gauge from teh time you start you car cold. It should raise up to 160 and then kind of hang there for a while then it will raise again as you car reaches its desired operating temp. If it goes up to say 180 or 190 and hangs there then rises, you have sending unit or gauge problem. Just double check the temp of the stat before using this method.

 

Of course you could be like ME, and buy a digital temp probe....good for all sorts of stuff....;-)))

GENE

 

Gene

There are A LOT of tools I want to buy and that is on my list. But it is down the list and will have to wait. Just thought it is an easy no cost test. Not the most accurate but does give an indication. I suppose he could just go to a radiator place and they will do it for free.

Chris

 

If your thermostat does work and your radiator has proper amount of water, the upper radiator hose will stay cool until the thermostat opens. So, if you grab the upper hose soon after starting a cold motor, wait until you feel it get warm and then check your gauge. It should be very close to your thermostat rating. And yes, it does open and close while driving, unless the cooling system is borderline on being inadequate in some way to cool the engine - only then will it stay open.

With a 160 thermostat, my L88 stays at 160 degrees while driving on the highway. With a 180, it stays at 180. If I left it out, the car would probably run at 150 degrees or less, not a good idea. City stop and go driving it stays open but with the Spal fans doesn't go over 205.

Chuck

 

I again disagree with COOK. If it were only for warmups and winter then only cars in the cold regions would have them and in warm weather you would just run nothing. There is a closely engineered cycle of heating and cooling that must take place. Its the same pricncipal of you A/c Compressor cycling on and off. If your car can run a low thermostat run it but if its sweet spot is higher than your thermostat you are just fighting yourself over and over.I have been bitten early on in life with someone saying just take out the the tstat and it will run cooler, MAYBE on the highway where there is lots of cool air blowing through the rad but in traffic where the only air moving is from the fan pulling the temp skyrockets. Proven over and over. Pull your thermostat and hop in traffic for 15-20 minutes at idle and watch it go way high. Thermostats are a necessary item and with some basic understanding of heat and airflow you can reverse engineer your cooling system to really work for you and not against you.

 

Subboz,

You are very correct, the thermostat is there for more than warmups and winter driving. Yes, it does allow the engine to warm up faster, but it also assures that the engine runs a minimum temperature for its efficiency AND longevity. If the temperature continues to climb, then the fan(s) increase the ability of the radiator to keep the engine below maximum limits, again for the engine's efficiency AND longevity.

But it doesn't have to cycle. If the water temp is above the rated temp of the thermostat, it will stay open - period. This is usually the case in city stop & go traffic. Once the car is moving above 30mph, the fan is really only in the way*, the air forced through the radiator by the car's forward motion will eventually bring the water temp back down to a point below the thermostat's temp rating and it will close, for a while.

Chuck

*A spinning propeller or fan that is spinning at a slower speed than the air trying to flow through it impedes the air flow, it doesn't boost it. Pilots use this effect as a brake to slow up air speed for landings with prop planes. A very high capacity 16" electric fan rated at 3000cfm would only move the air through the radiator at 24mph. I doubt if most Vette owners have even half that capacity.

 

Chuck,
Very eloquent way of putting that. I agree totally just couldnt get it into words.

 

Got an update for you. I took the vette out last night. Right before the drive, I decided to take a look at the plugs. The plugs looked fine but the gap looked too close. I measured them and most certainly, they were too close. So I pulled all of the other plugs to see if they were the same way. And they were. So I adjusted all of the spark plug gaps to .045. I then took it out to see how it would do. Just at regular, in-town speeds and low RPMs, the car actually stayed at about 160. I took it on a busier road and it went up to about 170 or 180, still maintaining a low RPM. A couple miles down, I pulled a U-turn and made an acceleration run. I took it to redline through the shifts, and then let off at 110. At this point the temp went to 210. I decided to take it down a busier road towards the interstate. Cruising about about 70-75, it did go about 210-220.

So it seems that if I keep the rpm down, the temp stays down. But if I redline, the temp goes up. Wouldn't this mean they there is nothing wrong with my fan clutch? Wouldn't this be pointing toward something like a missing lower radiator hose? It is a new radiator hose, I didnt know if the new ones are strong enough to hold the pressure or if they too needed a spring in them.

I have the air damn that mounts underneath the nose on order from Corvette Central. Please let me know what you think.

 

Hay, my 78 SA does the same thing!! I think its normal however, what is the parts number of that air dam, I think I want to get it :yesnod:

 

Also, I run a 160 therm.. If I'm running around town doing no more than 40 or 50 the temp hangs around 170 - 180.. If I'm doing 60 to 70 mph, the temp runs at 195 to 200. It will do this all day in any temp, I went on a run for about 2 hrs a few weeks ago in about 85 deg temps. During that entire time doing 60 to 75 mph it never went above 200 deg. I think this is normal and with many old timers (like me) I don't like to see it much above 180.

With a little work (like the air dam) and thought, you can get the temp to stay at 180 and no more all day. I have done it in the past..... two cars back I had a 69 Road Runner that I put a 160 therm in. new Rad, new fan (no clutch),new shroud, high cap water pump, can of water wetter and a solution of 30% prestone / 70% water. That baby NEVER went over 185 in any weather or heavy stompings :yesnod:

 

For a 73-79, corvette central part number 333066 (41.95) is for the air dam, 333067 is for the air dam mounting kit.(7.95)

I've got both on order.

 

my '81 has the stock 192-195 thermostat in it and it warms up to 195 in under 5 minutes and then stays there all day long. I had a 160 stat in there and it would run under 180. The thermostat is in there to maintain a minumum temp and operates even when the car is hot. Putting a lower themostat in will not help overheating problems


[Modified by stickboy, 8:12 AM 7/10/2002]