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'71 big block: problem with cooling system, or not?
My 1971 LS-5 has me a little worried. The water temp gauge used to indicate right at 210 whenever I drove the car. Recently, if the gauge is accurate, the gauge takes a few minutes to register anything, and then pegs right at the notch on the gauge between 100 and 210 and never goes much higher than that.
For example, on Saturday I drove the car 25 minutes in 57 degree weather with light traffic. The temperature never registered above the notch on the gauge between 100 and 210.
When I pop the hood after a drive, however, there seems to be a lot of heat coming off the coolant system. The expansion tank and hoses are all extremely hot to the touch.
Is this normal? If this post doesn't give enough information to indicate whether or not a problem exists, please let me know what else I can do to diagnose this.
The pic is the temp gauge 1.5 hours after the drive -- still close to where it was during the drive. So although the car never gets to "normal" operating temperature, the system is holding on to the heat long after the car is turned off.
I would get an infrared temp gun so you can get an idea of what the temps are at different points around the cooling system. You may just have a bad sensor. Check the wire going to it and make sure it isn't damaged. Also, If the radiator cap is several years old, replace it with one rated at least 16lbs..... although I would go as high as 20.
If you haven't made any recent changes to the engine, I would suspect a faulty sending unit or gauge.
A new sending unit is easy to change and you can get one at any auto parts store for a few bucks.
As stated above, make sure the connection is clean and tight.
+1 on sending unit.
Mine wouldn't move over 150 also.
A new sender and now she reads steady 210 as she should.
My original sender the center stem inside the resign became loose.
I got a nice reproduction from Wilcox and no more problems.
Old Car Bum is right on.
If its a gauge it will peg itself out at one end or the other.
Marshal
'71 big block: problem with cooling system, or not?
