Cooling Fan Questions

[SpeicherBimmer]

O-k, considering how many people have overheating issues I will probably get flamed for this, but here goes. I finally got my SPAL 1600 CFM pusher and 80* tstat installed. I wired up the relay to a 85/80 temp switch mounted in the tstat housing and got the fan installed nice and close to the radiator. I also made two openings in the front bumper underneath the plate mount for more airflow to the radiator. Once I got the system fully bled out, the car has gotten to just below the half mark when sitting for a while but usually sits just past the 1/4 mark while driving. I guess my "issue" is that when my fan kicks on ( usually just past the 1/4 mark) it stays on until about 10 mins after I shut the car off. I wouldn't care except for the fact that the fan draws so much power; the voltage gauge goes down by almost a full volt (from 14ish to ~13) when it is on. It also sounds like there is a tornado in the front of the car which makes it hard to impress the German honeys in front of McDonald's( yeah, I'm cool ). Seems kinda pointless for the fan to be running when I am cruising down the A60 at 90MPH.Should I go with a hotter temp switch? Should I move the switch to the radiator? I have it in the tstat housing as I think that would give a better reading as to the true coolant temp. Thoughts? Insults?

[jim325]

Isint it normally in the radiator? The tstat houusing probably get's a lot of heat from the block so I could see that reading hotter for longer than the coolant in the radiator.

You could always just wire it so the fan relay only get's power with the ignition key in the run position. You must have it wired so it get's battery voltage all the time. Do you have it wired directly to the battery or the positive junction block at the firewall?

[FLG]

Agreed

You should have it hooked up to a relay. If not, wire one up so wire the trigger to a switch source that only gets power with the key in the run position. There is minimal power draw so you don't need any crazy gauge wire here.

Sent from my Galaxy Nexus using Tapatalk 2

[CorvallisBMW]

^yup. Relay is needed. Or, simply use your stock auxiliary fan wiring.

[SpeicherBimmer]

Well this was a no AC car, so I don't have a stock relay. I do have the SPAL relay kit hooked up, but as jim325 guessed I have it connected to the battery positive. As for the radiator, I can see where everyone is talking about mounting the temp switch, but mine seems to be a solid piece of plastic. I guess I could tap it and mount it there if that really is the better spot. I took it on the ring today and she didn't come close to overheating once and my oil temp stayed around 80* the whole time..so I guess it's doing it's job.

On a side note, what are the cons of the fan drawing so much power? I have heard that it will weaken the spark a bit, but is it really enough to merit concern? Or is it running most of the time no issue other than the noise? A friend and I went to eat after the Ring and people kept coming up to ask me if something was wrong with my car since it was making such a racket

[kdkool]

Wire in a relay in series to with your fan setup (in between the temp sensor and fan). This would force the fan off when car is turned off but still turns on only after the temp sensor is set.

I plan on making a delay circuit to turn on the fan after a given amount of time (i'm thinking ~10 seconds). This is so that if I restart the car after it's up to temp (thermo switch is activated), the fan won't rob some cranking juice.

As far as high current fans... just make sure that the wiring is up to par for the current. Make sure the alternator isn't too undersized for your application. Especially if you have a high powered audio system.