View Full Version : Cooling question
hjoensy
03-24-2019, 05:29 PM
I have a 351w with first start today. Felt great.
It gets hot within a few minutes of starting and the radiator fan seems to kick on too late. I have 180 thermostat and it’s about 70 degrees outside here today with the car sitting.
What temperature is the fan supposed to kick on?
BadAsp427
03-24-2019, 07:35 PM
That will depend on the switch you have installed. The one that came with my kit came on at 180, but the thermostat is a 180. This caused my fan to come on and stay on all the time... I replaced the switch with one that comes on at 200 and off at 185 this way the thermostat and ram air will keep it cool as I'm driving it but when standing still, the fan can and does do it's job. I picked mine up from HERE (https://www.walmart.com/ip/0YRGEAMCMFU9) for $8.00.
How hot is too hot? If you have a 180-deg t-stat what running temp are you expecting? What high limit will you accept? What temp do you want the fan to kick on / off? And make sure your recovery tank is sized correctly & the pressure cap is rated for the pressure for your desired operating temperature. Your coolant will expand and contract with temperature and unless you have an expansion tank or leave enough room in the radiator coolant will puke into a recovery tank. The more temp variation the more expansion -- and this can be calculated so you don't have to guess at the size tank you need.
A t-stat is usually rated at the temp it starts to open and may fully open 10-15 degrees above that. If you're not sure what you have you can easily check the actual fully open temp and the fan switch open / close temps by placing them in a pan of water with a thermometer on your stove and slowly bring up the heat. Use your ohm meter on the switch to determine when the switch is open (off) and closed (on). You can visually see the t-stat open and close.
Avalanche325
03-25-2019, 06:29 PM
Getting hot, not just warm, within a few minutes? That is an indication of air in the system.
Where are your sensors located?
What is your definition of that fan kicking on too late? Mine takes a long time before it comes one from startup.
Do you see coolant flow when the temp comes up with the cap off? I always test new thermostats.