This is a gasser question, I would go to the vortex.. but.... - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• This is a gasser question, I would go to the vortex.. but.... by 8v-of-fury on 18 Sep, 2009 11:43
•   We all know how the vortex is... lol
  
  SO! My fan has been having issues lately with no coming on until the car reaches a fairly high temperature.. so i wired in a manual switch to the fan..
  
  I was using the car as a running aid in trying to jump another project (360 chrysler) which needed a big power source.. SOO with it idling i guess it sat there long enough to get REALLY hot and blow a rad hose, and cover me in hot hot hot coolant yet again in my life.. I ran through the coolant spray, not caring if i got burnt to get to the ignition and shut her down! NOW I know this was caused by me not running the fan.. it was %100 my fault. however now after replacing the hose and filling her back up with FreezE she seems to run hot!
  
  
  
  This was taken bombing it down a back road home this morning doing about 115 km/h with the fan on to help.. sat there the whole way home, usually it sits hovering over the little thermometer picture..
  
  I think the thermostat is faulty here..how do i tell if the coolant is circulating properly? upper and lower rad hoses hot? or should the bottom one be cooler as it just passed through the rad? how is the thermo replaced?
  
  She started fine this morning, and ran fine on the way home.. no stutters, no loss of power.. Did I get lucky? that it blew a 25 year old hose before it did damage and gave me time to shut it down? Also.. Where is the sensor that tells the fan to turn on? Is it in the rad? and the temp sensor is in the head? if the thermo were faulty the rad wouldn't get as hot as the head.. allowing me to see a hot temp reading and the fan to not want to turn on correct?
  
  What is the plan of attack here boys? I know im an idiot so leave that part out.
  
  ...Hey this may just be a sign from god to get rid of the 1.7 and get that 1.6 in there 
  
  Tia,
  
  8v
• #1 by maxfax on 19 Sep, 2009 19:36
• Crazy gassers...    Had to double check Alldata on this one...
  
  The fan switch is in the bottom of the LH rad tank, temp gauge is in the head.. 
  
  Do you have some means of checking the coolant temp other than with the gauge?? The termostat could be fubarred as they aren;t real happy about being cooked..  Could be that maybe your gauge has decided to act screwy too...  Both rad hoses should get hot after sittig and idling with no fan..   Once some air passes though the rad (driving or the fan) the lower hose woudl get a tad cooler....
  
  
  Thermostat is under the water pump,  pretty much all the same as a proper engine  ..
  
• #2 by Smokey Eddy on 25 Sep, 2009 03:58
• Alldata to the rescue. I used that program extensively while in mechanics 11 and 12 in highschool.
  good program.
• #3 by jtanguay on 25 Sep, 2009 18:41
• make sure your rad fan runs at both speeds by jumping the leads on the thermoswitch harness. i've had problems like this myself, and it is usually caused by a slowly dying fan.  sometimes it will work, and sometimes it won't.  your best bet is to chuck that rad fan, and buy one (or two) of those ebay fans.  OR if you're strapped for cash, get a rad fan from a car WITHOUT a/c!
• #4 by 8v-of-fury on 25 Sep, 2009 20:16
• oh yeah, i kept the rad and fan outta the 91 i got my diesel engine from lol. Both speeds work.. i just have it wired up to the low speed.. the thermostat switch seal will still kick the fan on.. but it lets it get preeeeeeeeeety hot before it does anything about it.. So i dunno if i trust it right now.
• #5 by macka on 29 Sep, 2009 20:47
• so wire in an override switch and switch it on when you feel it needs to be ran.
• #6 by 8v-of-fury on 29 Sep, 2009 21:04
• what will happen if i am giving it power through my switched source.. and the relay goes to kick it on? what happens then?
• #7 by maxfax on 29 Sep, 2009 21:11
• Nothing..  The fan'll keep on running..
• #8 by 8v-of-fury on 29 Sep, 2009 21:12
• Well then that seems like a plan. What decides when the fan comes on? the thing bottom drivers tank of the rad? is it easy to replace?
• #9 by maxfax on 29 Sep, 2009 21:16
• Yes, the sensor in the rad kicks the relay which runs the fan..   For the sake of not having high current loats routed to the passenger compartment I would connect your manual switch to the wires on the temp sensor.. Then your switch will just trip the relay and kick the fan..     If you're not so trusting of the wiring and relay then just route your power from the batt to your switch then too the fan..  But make sure you use a fairly heavy switch and wire....  Fuses are a good thing too I;ve been told..
• #10 by 8v-of-fury on 29 Sep, 2009 21:30
• OH hell no Brett (that was your name right? i think...) I have it relayed. Battery, relay, fan. total wire run of like 11" lol and then nice small convenient wires to and from my switch
• #11 by maxfax on 29 Sep, 2009 22:02
• You got it, on all accounts..    But if you are looking for a more exciting twist, just run a wire from the battery and the fan motor to the passenger compartment..  Leave about 1-2" bare at the ends inside..  Whenever you need cooling just twist them together!    This procedure also works dandy for a failed ignition switch!