Thermostat/Temperature Question
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Thermostat/Temperature Question
68 327 L79 350 HP motor
Thermostat I believe is 180
Temperature on gauge in console reads almost at 210 mark; Infrared thermometer on thermostat housing reads 235 and on upper heater hose reads 180 (checked temps while motor running, idling in neutral)
Why the discrepancy and how do I know what the actual temperature is of the coolant?
Thanks in advance for any input
Kurt
Thermostat I believe is 180
Temperature on gauge in console reads almost at 210 mark; Infrared thermometer on thermostat housing reads 235 and on upper heater hose reads 180 (checked temps while motor running, idling in neutral)
Why the discrepancy and how do I know what the actual temperature is of the coolant?
Thanks in advance for any input
Kurt
Safety Car
Joined: Oct 2004
Posts: 3,923
Likes: 733
From: Youngstown Ohio
Actual temp. may be "all of the above".....the thermostat opens at 180, but does not control the temp. after that point; the sender in the head is a resistor that varies with with the heat of the coolant flowing over it at that point, sending info to the gauge.....usually pretty accurate. The coolant in the system is lower in temp. after it leaves the radiator freshly cooled, so your thermometer reading depends on where along the route you put it.
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Just checked the part number and it turns out I am running a 195 degree thermostat.
The thermometer readings were taken at the thermostat housing itself and the other reading was taken on the upper hose approximately 2 inches from the housing.
Kurt
The thermometer readings were taken at the thermostat housing itself and the other reading was taken on the upper hose approximately 2 inches from the housing.
Kurt
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
Kurt
your L79 should have a 180º t-stat in it.
I always checked temps off the upper rad hose but in posts I saw that Tomn DeWitt recommends taking a reading off both the t-stat housing and the upper rad hose housing on the rad and averaging the two numbers to get yourself a pretty accurate coolant temp. Tom is the cooling system expert so probably best to follow his method
your L79 should have a 180º t-stat in it.
I always checked temps off the upper rad hose but in posts I saw that Tomn DeWitt recommends taking a reading off both the t-stat housing and the upper rad hose housing on the rad and averaging the two numbers to get yourself a pretty accurate coolant temp. Tom is the cooling system expert so probably best to follow his method
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Barry,
Using the formula you listed, my average temp comes out to about 207.5 degrees. (180 at hose 235 at housing)
That also means my gauge in the car is relatively accurate sinc eit reads just below the 210 mark.
Since I am running a 195 thermostat, I guess I am in the ballpark with the 207.5 since it was in the garage idling when I took the temp and the airflow through the radiator in the garage is minimal, not like when I am driving..
I used the 195 stat because everything I had read indicated that my car requires the 195 vs the 180.
Kurt
Using the formula you listed, my average temp comes out to about 207.5 degrees. (180 at hose 235 at housing)
That also means my gauge in the car is relatively accurate sinc eit reads just below the 210 mark.
Since I am running a 195 thermostat, I guess I am in the ballpark with the 207.5 since it was in the garage idling when I took the temp and the airflow through the radiator in the garage is minimal, not like when I am driving..
I used the 195 stat because everything I had read indicated that my car requires the 195 vs the 180.
Kurt
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
Kurt, yes, it's very possible that you are running 207º because of the 195º t-stat. your minimum temp would be 195º. 207 º is not too much over that.
I'm 99% sure you should be running a 180º t-stat in your car. the L79 in your car is basically identicle to all the previous L79's in the C2's which were all 180º t-stats.
the 195º t-stats were for later cars with all the emission "crap" on them because the higher operating temps were good for reducing HC emissions. There is no reason you would need a 195º t-stat on your L79.
I'm 99% sure you should be running a 180º t-stat in your car. the L79 in your car is basically identicle to all the previous L79's in the C2's which were all 180º t-stats.
the 195º t-stats were for later cars with all the emission "crap" on them because the higher operating temps were good for reducing HC emissions. There is no reason you would need a 195º t-stat on your L79.
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Barry,
I do have the emmisions crap.
My car was the first year for the A.I.R (Air Injection Reactor) pump system and that is exactly the reason I was given for the 195 thermostat. I have the exhaust manifolds with the holes and the pipes and all that crap. Problem is I still need to buy the correct Smog pump and was quoted a price of $1800.00 for the CORRECT pump with fittings etc.
We threw this crap away in the seventies and now it costs an arm and a leg to get it and make the car factory correct. I don't want it but since I have spent so much time and money to get this car back to factory original, the smog pump and the ignition shielding are the last items I need for my restoration (and the SnakeOyl shoulder belts for $795.00). It never ends. Fortunately, I will never sell it since I've owned it since 1972 so I don't have to worry about getting my money back. That will never happen. The car will go to my son who is already anxiously waiting for it. (He's 29 years old, and a great kid so he deserves the car)
Kurt
I do have the emmisions crap.
My car was the first year for the A.I.R (Air Injection Reactor) pump system and that is exactly the reason I was given for the 195 thermostat. I have the exhaust manifolds with the holes and the pipes and all that crap. Problem is I still need to buy the correct Smog pump and was quoted a price of $1800.00 for the CORRECT pump with fittings etc.
We threw this crap away in the seventies and now it costs an arm and a leg to get it and make the car factory correct. I don't want it but since I have spent so much time and money to get this car back to factory original, the smog pump and the ignition shielding are the last items I need for my restoration (and the SnakeOyl shoulder belts for $795.00). It never ends. Fortunately, I will never sell it since I've owned it since 1972 so I don't have to worry about getting my money back. That will never happen. The car will go to my son who is already anxiously waiting for it. (He's 29 years old, and a great kid so he deserves the car)
Kurt
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Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
Kurt
my apologies, I didn't know the L79 in '68 had the A.I.R system on it.
Hmmm, I wonder if they all did or only California cars.
Regardless, if you have the A.I.R system on it or are putting it back on to bring it back to a restored stock condition than the 195º would be correct. Sorry for the confusion or wrong info
my apologies, I didn't know the L79 in '68 had the A.I.R system on it.
Hmmm, I wonder if they all did or only California cars.
Regardless, if you have the A.I.R system on it or are putting it back on to bring it back to a restored stock condition than the 195º would be correct. Sorry for the confusion or wrong info
