Postby FI Spyder » 05 Sep 2023 16:15
Looks like the rad needs to be recored at your local radiator shop. Re: cooling: If the rad is (partially) blocked, it will have a hard time cooling the motor. A blocked rad can be cleaned (best to get it professionally cleaned at that point). A core in the heater can become blocked as well, in standard form the flow is constantly going through it (heat is cut out by flap in heater alone). In A/C cars the flow to the heater is actually shut off.
Thermostats are design to fail in open position (failure to get heat to the heater core). That's what the spring is for. When the thermostat failed in my Integra, I could get zero heat in the cabin even though it was above freezing. I knew exactly what it was even though that's the first time it happened to me (ever). With that design, the engine can't overheat due to a failed thermostat (safety design).
The cooling system will slowly lose coolant with use. The difference between when it's too high (expels out the overflow tube when hot) and too low, low coolant light turns on if you have it (only newer ones) isn't very much. The coolant level is meant to be checked periodically (like when you check oil level) but as people never did that (how do you open the hood?) they put the light in there to warn you (sometimes a PITA but a good failsafe).
In a properly operating cooling system, the needle won't move from 1/4 from cool running to traffic jam hot driving, more than a needle's width as Hasbeen says.
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 2013 Volt - Yellow TCT