Cooling fans packed up.
Discussion
Well last weekend my cooling fans decided to completely pack up. I`d had my suspicions that they werent working correctly the last few times out.
Anyway a bit of testing showed relay and fuse ok and the fans themselves worked fine when powered up straight to the battery. Then tested the fans positive feed from the relay to where this positive wire appears at the front of the car at the fans. Result was huge resistance in the line. Only about 5 volts getting through. clearly not enough umph getting through to power the fans.
Pulled the fuse box out and found the power feed to the fans. Interestingly this wire had had a 2nd wire soldered onto it. My theory here is that with my car being a `92 precat it most likley started off life with a single fan and this 2nd wire was added later in life when converting to twin fans. So we now have two wires from the fuse box but only 1 exiting at the front of the car to feed the fans. The two obviously go into one somewhere, i`m presuming who ever did this mod ran the 2nd added on wire as far as they could, most probably to somewhere behind the dash before the loom becomes innaccesible. I`m guessing its going to be this join where the resistance is.
Looking at this setup i had both fans running off a single 30amp relay, a single 25a fuse and wiring clearly not up to the job. Cant believe the fuse never blew, No wonder it failed.
Any way its now all rewired with decent size cable, two 40amp relays and two fuses one for each fan as per later cars. The 2nd relay i have fed from the back of the alternator and hidden it beneath the o/s headlight away from the weather.
Sorry no pics but just a heads up for pre cat owners who may have the same mod if running two fans.
Anyway a bit of testing showed relay and fuse ok and the fans themselves worked fine when powered up straight to the battery. Then tested the fans positive feed from the relay to where this positive wire appears at the front of the car at the fans. Result was huge resistance in the line. Only about 5 volts getting through. clearly not enough umph getting through to power the fans.
Pulled the fuse box out and found the power feed to the fans. Interestingly this wire had had a 2nd wire soldered onto it. My theory here is that with my car being a `92 precat it most likley started off life with a single fan and this 2nd wire was added later in life when converting to twin fans. So we now have two wires from the fuse box but only 1 exiting at the front of the car to feed the fans. The two obviously go into one somewhere, i`m presuming who ever did this mod ran the 2nd added on wire as far as they could, most probably to somewhere behind the dash before the loom becomes innaccesible. I`m guessing its going to be this join where the resistance is.
Looking at this setup i had both fans running off a single 30amp relay, a single 25a fuse and wiring clearly not up to the job. Cant believe the fuse never blew, No wonder it failed.
Any way its now all rewired with decent size cable, two 40amp relays and two fuses one for each fan as per later cars. The 2nd relay i have fed from the back of the alternator and hidden it beneath the o/s headlight away from the weather.
Sorry no pics but just a heads up for pre cat owners who may have the same mod if running two fans.
carsy said:
Well last weekend my cooling fans decided to completely pack up. I`d had my suspicions that they werent working correctly the last few times out.
Anyway a bit of testing showed relay and fuse ok and the fans themselves worked fine when powered up straight to the battery. Then tested the fans positive feed from the relay to where this positive wire appears at the front of the car at the fans. Result was huge resistance in the line. Only about 5 volts getting through. clearly not enough umph getting through to power the fans.
Pulled the fuse box out and found the power feed to the fans. Interestingly this wire had had a 2nd wire soldered onto it. My theory here is that with my car being a `92 precat it most likley started off life with a single fan and this 2nd wire was added later in life when converting to twin fans. So we now have two wires from the fuse box but only 1 exiting at the front of the car to feed the fans. The two obviously go into one somewhere, i`m presuming who ever did this mod ran the 2nd added on wire as far as they could, most probably to somewhere behind the dash before the loom becomes innaccesible. I`m guessing its going to be this join where the resistance is.
Looking at this setup i had both fans running off a single 30amp relay, a single 25a fuse and wiring clearly not up to the job. Cant believe the fuse never blew, No wonder it failed.
Any way its now all rewired with decent size cable, two 40amp relays and two fuses one for each fan as per later cars. The 2nd relay i have fed from the back of the alternator and hidden it beneath the o/s headlight away from the weather.
Sorry no pics but just a heads up for pre cat owners who may have the same mod if running two fans.
CarsyAnyway a bit of testing showed relay and fuse ok and the fans themselves worked fine when powered up straight to the battery. Then tested the fans positive feed from the relay to where this positive wire appears at the front of the car at the fans. Result was huge resistance in the line. Only about 5 volts getting through. clearly not enough umph getting through to power the fans.
Pulled the fuse box out and found the power feed to the fans. Interestingly this wire had had a 2nd wire soldered onto it. My theory here is that with my car being a `92 precat it most likley started off life with a single fan and this 2nd wire was added later in life when converting to twin fans. So we now have two wires from the fuse box but only 1 exiting at the front of the car to feed the fans. The two obviously go into one somewhere, i`m presuming who ever did this mod ran the 2nd added on wire as far as they could, most probably to somewhere behind the dash before the loom becomes innaccesible. I`m guessing its going to be this join where the resistance is.
Looking at this setup i had both fans running off a single 30amp relay, a single 25a fuse and wiring clearly not up to the job. Cant believe the fuse never blew, No wonder it failed.
Any way its now all rewired with decent size cable, two 40amp relays and two fuses one for each fan as per later cars. The 2nd relay i have fed from the back of the alternator and hidden it beneath the o/s headlight away from the weather.
Sorry no pics but just a heads up for pre cat owners who may have the same mod if running two fans.
When you upgraded to the 500 engine did you also upgrade your fans to 500 fans with the deeper motors? When I bought my Precat it also was already upgraded to twin 400 fans and although they have been very reliable it may still be worth I check my wiring.
Thanks for the detailed warning.
Cheers, Steve
Edited by stevesprint on Thursday 17th November 20:36
Here’s the different fans with the more powerful motors, they are all a straight swap.
Griff 500 VA10-AP6-47A (or VA10-AP70-61A)
T350 etc VA10-AP50/C-61A
Precats VA10-AP9/C-25A
If you are not having cooling issues I wouldn’t suggest upgrading to old 500 fans as they pull over double the amps, however I believe SPAL recently updated our fans with brushless motors that use less juice, I’m not 100% sure but might be worth investigating if anyone requires new fans.
RV8 - I'm doing my bit for global warming
Griff 500 VA10-AP6-47A (or VA10-AP70-61A)
T350 etc VA10-AP50/C-61A
Precats VA10-AP9/C-25A
If you are not having cooling issues I wouldn’t suggest upgrading to old 500 fans as they pull over double the amps, however I believe SPAL recently updated our fans with brushless motors that use less juice, I’m not 100% sure but might be worth investigating if anyone requires new fans.
RV8 - I'm doing my bit for global warming
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