Car in question is an '81 Jetta Special Edition 1.6NA with 5-speed and A/C.
I have had a slow coolant leak since I bought the car 6 months ago. I've been replacing and repairing parts gradually and a few weeks ago I bought a replacement water pump and housing and a "stock" 87C thermostat. I haven't yet replaced the water pump but I have inspected it on the car and I believe the pump housing and thermostat are the original parts from the factory. Not long after I bought the new pump and thermostat I noticed a leak in the radiator. When replacing the radiator I discovered that my rad fan switch is stamped "72C," which seems very low. I haven't pulled the thermostat so I'm not 100% sure it's a 72C but it appears to match the fan when it comes to operating temperature.
Does anyone know why my car would have a 72C cooling system from the factory? The car was originally sold in California but I don't know where within CA, maybe the desert, maybe the chilly north coast. Did VW specify the cooling system set point based on the climate of the cars intended point of sale? I think I saw a chart somewhere on this forum indicating that cars with factory A/C were equipped with a colder t-stat. Maybe VW installed 72C systems on cars with A/C for sale in hot climates? Does anyone know if this is the case? Has anyone else discovered their factory cooling system was set for anything other than 87C?
I haven't had any overheating issues, in fact I've been concerned about running too cool. I usually practice the "Don't fix it if it ain't broke" philosophy, but I will probably try a warmer t-stat and fan switch. San Francisco is not very warm and winter is approaching...
Turns out my stock thermostat was 82C. I swapped in a new 87C thermostat and it works like a charm. I think the old thermostat was tired and probably opening below 82C. My temp gauge used to sit between 1/4 and 1/2, now it sits steady at 1/2. I haven't swapped fan switches, so I'm still running the 72-79C switch. It seems to be working well with the 87C thermostat. I need to get some more miles with this setup and if the rad fan switches on excessively I'll try a warmer switch.
Here's a dumb question: does the rad fan come on regardless of vehicle speed?
On our old Diesel VW's Yes.. It'll even kick in with the engine off if conditions are correct..
Thanks, that's what I figured. I think I'll bump the fan switch to a 77/82 from it's current 72/79.
Here's another dumb question: why are there 2 temp specs for a single-speed fan switch? What does the 77/82C mean exactly? Does it mean the fan will activate when the temp is somewhere between 77 and 82?
Do the rad fan switches lose accuracy and precision over time?