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1998 RAV4 Hardtop.
Due to a relatively minor accident I have a crack in the top inlet neck of my radiator. I packed it with resin putty but that hasn't stopped it from leaking.
I did buy a new radiator but it seems very complicated to fit it - seems like the A/C condenser needs to be removed or at least pulled forward and I can't see that there is room to do that. And also the lower radiator support has been bent upwards, which caused the top inlet neck to hit the hood latch crossbar (hence the damage) and the radiator now sits in a slightly raised position with the top inlet just barely under the cross bar. A mechanic that I saw about fitting the new radiator told me that this would have to be pulled down with an hydraulic Porta-Power device, although since the front area is supposed to be a crumple zone and also it's just a support bracket then I would not expect that it is such a hefty piece of metal.
I have lived with the problem for 3 years now, just topping up the radiator before start-up. Only takes about 1 liter or less so it's not a huge problem. I have removed the valve from the radiator cap to prevent pressure build up in case it weakens the inlet neck any further, but of course water (not using coolant - too expensive to keep topping it up) is lost during a trip and when I get stuck in traffic the temperature can go up. The radiator fans do operate as they are supposed to, but I want to have alternative manual control. Incidentally, after topping up, the temperature gauge is very slow to reach the (normal) mid point, only really getting there if I am in slow traffic or stopped. And it does not go higher than half way, even when I have been stuck in traffic and seen steam rising from under the hood. Only once did the gauge ever get to about 75%, and that at least confirmed that the gauge was working because I had wondered if it was faulty.
Anyway, I am paranoid about it overheating and blowing the head gasket (or worse damage), so being able to manually switch the fans on would be reassuring. Looking at the electrical diagram I see a connection from the FAN NO. 1 RELAY going to earth through the A/C single pressure switch and also the A/C water temperature switch. Although that designation is confusing if it is simply the radiator water temperature switch to control the fans and what has it got to do with the A/C? These two switches are shown closed in the wiring diagram so I assume the water temperature switch will open when the temperature is high enough to operate the fans which will cause the relay to drop out. But this is confusing since the relay contact directing voltage to the radiator fan motor is also shown closed. Therefore if the relay does drop out as I assume then the supply circuit to the radiator fan would in fact open and stop the fans rather than start them running. Anyway, if I assume that the two switches are a normally closed circuit then a switch I might fit for manually operating the fans would need to open this circuit. Is this correct? I would be fitting this manual over-ride switch into the LG-B wire (presumably light green/blue?) that is shown in the diagram as coming from the relay and going to the A/C single pressure switch.
I could, of course, simply experiment and try either opening this circuit and see if the fans operate, or shorting it. But I thought I would ask the question anyway and also ask if having a manual over-ride is going to mess up the general automatic operation of the fans or the A/C system. I can't see that it will because I am simply fitting a bypass for the water temperature switch which will operate the fans in the same way that the temperature switch would do itself if the temperature got too high. And since there are two fans then the wiring diagram seems to show that one is for the A/C condenser and the other for the radiator, although at least once when the fans operated due to water temperature I checked and saw that both fans were operating (A/C was off) and I would like both fans to operate by manual control.
Regards to all and thank you kindly for any help.
 

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Is there any reason that you cannot just forget about the automatic fan and just install a toggle switch to control the rad fan manually. The wires going to the fan will be heavy enough to carry the current. One wire will be the ground or earth, don't use that one, just leave as is. The other wire will supply power to the fan. Cut that and tape off the end that would normally supply power to the fan. Take the other end of the wire (the one going to the fan) and using a butt connector run a wire back to a toggle switch mounted inside the cab at a convenient location. On the other terminal of the toggle switch run a wire to the fuse panel and find a location that has a suitable fuse to piggyback off, or run the wire back to the positive battery terminal, include an inline fuse of suitable amperage. Use at least 14ga. wire, 12ga would be better and remember that the fan will continue to run after you turn off the ignition and discharge the battery if you don't turn it off manually.
 

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The reason the temp. gauge takes longer to show that it's getting hot is because you have the radiator cap loosened to prevent pressure from building up and causing a larger leak, cooling systems are designed to run with pressure inside, no pressure=less heat, this is probably related to the fans not automatically turning on, so don't butcher up your wiring just yet.

The fix is one that you might be able to do yourself, if you have tools, no tools=no DIY fix! But the fix requires lifting the hood and draining the coolant, all of it, then pulling out the a/c condenser hopefully without disconnecting its hoses, there will be brackets to be dealt with, don't mix them up, label them and write down exactly where they go. Then yank the radiator hoses, the fan wires, etc. until you can get the radiator out.

Next you need to determine what exact metal part under the radiator is bent upwards, then bend it back downwards, this can be done with a heavy hand-mallet and an appropriate length of hardwood lumber like a 4x4 (100mm x 100mm) and beating the bent metal back down to where it should be. This can be a tough job, but it's VERY satisfying, you get to take out all your aggressions on it. Inspect the metal carefully, if it needs "massaging" then switch to another smaller hammer until the bent metal appears to be in its original location. Don't bend it too far downward, check the radiator fitment along the way.

When you're satisfied with the fit, meaning the new radiator fits, slowly close the hood making sure there is no contact between the two and nothing is going to interfere with reassembly, once that is done it's just a matter of putting everything back in the reverse order it was disassembled in. Voile'

Now add antifreeze because antifreeze also lubricates the water pump bearings, it's not just for cold weather, it needs to be your year-round coolant, and the water pump has been abused long enough with just water. Keep in mind that this is a fun learning experience, and it always helps to have a knowledgeable friend there to pitch in. Good luck.
 

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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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I totally agree with prospector!

You don't, I repeat don't have to remove the condenser, you have to remove the fans first then remove the hoses, disconnect the fan sensor, unbolt the supports, pull the condenser as far forward as you can, and finally lift the radiator out. When I was pulling my fans some of the bolts were heavily corroded and I used a small angle grinder to cut the bolts.

Not using antifreeze is BAD!!!! The antifreeze has lubricants and corrosion inhibitors. You can cause a water pump failure, cause your freeze/expansion plugs to corrode and leak, cause radiator corrosion, not to mention it cools a lot less efficiently. I assume you are using tap or well water which has all kinds of bad stuff in it for car engines. Also, not having a sealed pressurized system prevents the system for cooling properly as the water boils at a lower temperature when not under pressure and may be why your fans don't work.

See my thread - http://www.rav4world.com/forums/85-4-1-faults-fixes/243105-cooling-system-rebuild.html

By the way, I haven't had any problems with the fans I'm using, they are much quieter and appear to cool better than the OE ones. Being the fans are so slim I was able to install my new radiator with the fans attached which made for an easy install.

A fan sensor is not expensive if you need a new one. You can go to a junkyard and get a pull for radiator mounting frame and I believe it just bolts in. However if the "frame" that protrudes to the bumper is bent that would require straightening.
 
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