cooling system help

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DaveT
Posts: 52
Joined: Sat Mar 15, 2008 9:24 am
Your car is a: 1978 Spider
Location: Warwick, Rhode Island

cooling system help

Post by DaveT »

OK, I need help. I replaced the thermostat & hoses on my '78. (Thermostat was really old and the car lately began running a little hot.) A few years ago when I did the timing belt, water pump, etc, I installed the 'T' in the heater hose and filled the system through that and it worked perfectly. Did the same thing this time but now, when I start the car the temp gauge goes beyond the '0' of the 190 and heads to the red zone and the fan doesn't come on. (the temp senders are only a few years old). The thermostat is installed correctly - I used the original as the 'template'. The lower rad hose never warmed up that much and the bottom of the radiator (an Allison Automotive aluminum one about 8 years old) was hardly warm. After the 3rd attempt at burping I broke out the IR thermometer. When the temp gauge is around 210, the IR is reading 95 degrees on the drivers side of the radiator top and about 88 on the passenger side. The top rad hoses are reading 120+ degrees and the lower one is 90 degrees. The bottom of the radiator is 80 degrees. I'm hesitant to keep it running because I'm not sure how off the temp gauge might be. I'm hoping there's still air in there but I'm not getting anymore bubbles when I massage the hoses.
Dave T
Warwick, RI
'78 Black Spider
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: cooling system help

Post by 18Fiatsandcounting »

I think this question was adequately answered on Mirafiori, but the likely 2 possibilities are: 1) thermostat installed incorrectly, or 2) an air bubble in the top of the cylinder head or in one (or more) of the thermostat outlets/hoses.

-Bryan
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