removal of dummy waterpump

1991 TOYOTA 4RUNNER
300,000 MILES • 6 CYL • 4WD • AUTOMATIC
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TREVOR HOULT
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i have a 1991 toyota 4runner and the dummy water pump has failed, and they cost heaps and was wondering if i could use 2-10inch thermo fans to replace clutch fan
May 13, 2011 at 12:59 PM
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WRENCHTECH
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No, that wouldn't work well. The viscous fan is thermostatically controlled through hydraulic solenoids for both temperature and A/C pressure. Electric fans would provide no thermostatic control nor a means to mount the drive belt. Repair the car the way it was built.
Apr 29, 2020 at 10:34 AM
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FIXITMR
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interesting idea. if the fan blades can be removed from pulley i dont see why not? you would just need some kind of thermo switch to activate fans automatically.
Apr 29, 2020 at 10:34 AM
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WRENCHTECH
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Temperature is only half the problem. The A/C inputs to the fan controls also.
Apr 29, 2020 at 10:34 AM
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FIXITMR
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so you would just need feed from a/c signal to trigger fans? maybe thru a relay tapped off the compressor clutch? nothings impossible with determination?
Apr 29, 2020 at 10:34 AM
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WRENCHTECH
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That would only give you a full on and full off and nothing regulated by the pressure. It could end up being too much fan at times.
I don't advise trying it. The old one still has to be usable enough to carry the belt.
Apr 29, 2020 at 10:34 AM
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FIXITMR
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do you think the fan speed option was added as a noise abatement issue like say when idling in a drive thru? in other words is it really necessary? cant imagine what too much fan if thermo controlled would mean otherwise?
Apr 29, 2020 at 10:34 AM
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WRENCHTECH
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It means a lot. Too much fan in cool weather will lower the A/C pressures too much and cause freeze up and compressor starvation. Most cars have the defrosters wired to run the compressor to remove moisture.
Apr 29, 2020 at 10:34 AM
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FIXITMR
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that's probably the real reason. cold weather freeze up when they added the moisture removal trick. wonder when that all started?
Apr 29, 2020 at 10:34 AM
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TREVOR HOULT
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the a/c runs of the ballancer pully so all i need is a thermostat switch to activate fans at temp
Apr 29, 2020 at 10:34 AM
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WRENCHTECH
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No, that is not true. The A/C also interacts with the fan.
Apr 29, 2020 at 10:34 AM
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TREVOR HOULT
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please explain how as i have to do this mod as it is my only car and need it so want to cover all my basses as my last hope in getting part in not there anymore
Apr 29, 2020 at 10:34 AM
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FIXITMR
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changing over does seem like a more complex job then just replacing bad water pump. i would hesitate to undertake such a project. i have been known to plug weep holes though to get a few extra miles out of a pump till funds were sufficient.
Apr 29, 2020 at 10:34 AM
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TREVOR HOULT
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well job done but only need 1 10inch thermo pushes more than enough air around but i did need to get a good thermo fan switch other than that works well and heaps quieter and no a/c probs all works the same as it was before with a saving of around $800
Apr 29, 2020 at 10:34 AM
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WRENCHTECH
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No, you don't know that you have no problems and you won't realize that you do until the day your A/C compressor seizes but you're not listening to anything you've been told anyway.
Apr 29, 2020 at 10:34 AM
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FIXITMR
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well, when cold weather arrives you may want to disconnect compressor electrically as a safeguard. be neat if you posted a picture of the change you made.
Apr 29, 2020 at 10:34 AM