My 1995 4Runner, 3.0, Auto, 2WD has recently started overheating this summer. So, with a little help from my mechanic buddy, I've been throwing money at it trying to find a solution. We've done everything except chase/replace head gaskets. I'm aware of the reverse installation issue but these were replaced 8 years ago and there has never been any indication of a problem.

I'm here today to ask about the electric radiator fan. Mine is not running at all even with the engine well heated up. I unplugged it and hit it with 12v. It made a horrible racket and the blades didn't turn. Its not frozen up. I checked to see if there was 12v from the control/sensor and nothing there.
So, first...I'm pretty convinced that the fan is bad. I guess a generic replacement is the way to go?
Second...can't say yet about the controller without doing some further checking.

I guess I'm looking for some validation that I'm barking up the right tree and would appreciate any tips regarding this.

Thanks,
Bill

 

The electric fan that you have on your 4Runner is aftermarket, right?

To my knowledge, all of the 3VZ-E engines came from the factory with a mechanical fan with a viscus fluid coupling.

If this were my 4Runner, I would install a factory mechanical fan with fan clutch. The factory fan cools pretty darn well. Most electric fans people have installed for these engines just don't move enough air to keep the engine cool.

 

It has the "normal" belt driven/clutch fan and thats working properly. The electric fan I'm referring to is on the front of the radiator. It may well be something aftermarket. I bought the vehicle used 10-12 years ago and just don't know about it.
Here on the island the speed limit is 35 mph and its hard to routinely get the fan up to speed and I think this could be why a helper fan was added if in fact its not original. I've never had to give it any thought before now but it seems like a good idea in this environment.
Edit...I might add that this fan looks suspiciously similar to a Dorman fan I see at AutoZone. The fan is billed as an Air Conditioner Condensor Fan.

 

Ah, yes.

What you are seeing is the Air Conditioner Condenser fan.

That fan should only come on when the Air Conditioning is on. It sounds like it is bad.

Your engine should not overheat with just the normal mechanical fan, so you also have another problem.

Let's backup a little bit. Can you tell us what you and your mechanic buddy did so far? The more details the better.

 

Like all old87Yota said^^^.
Search the forum for all that people did to troubleshoot their overheating problems.

 

Ok, catching up.
The water pump/timing belt have been changed. No slippage of the fan clutch. Engine flushed. Thermostat wasn't installed but I put one in. (correctly). I've read other people's posts until I'm dizzy - haha. The only thing not done is check on the head gasket(s). Gauge sensor replaced...it broke when I tried to pull the connector. Fresh coolant in it. I'm probably forgetting something!

I'm running out of ideas then I noticed this additional fan. Yes, apparently it is stock. The A/C is not functional and hasn't been for a long time so it has not called attention to itself. I have no idea how long the fan as been defective. As I understand you it only runs when the a/c is on? It sure seems like it might be essential in other times, if not then certainly an advantage. The Ac coil completely covers the radiator and the fan covers at least half of that.

Anyway, I pulled that fan and the blade assembly has broken away from the motor. I don't know yet if that's fixable. I'm in the middle of things right now.

Thanks all.

 

A little something a lot of people don't think about is the fan shroud. It makes a difference in the way the stock fan and clutch cools. Including the little clip-on part on the bottom.

Is the fan shroud still there and all together? Without it, overheating is a possibility.

Also, the thermostat: I am no mechanic at all, but I've been told by several professional mechanics that it's important to have the thermostat in the system. Even when it's open, it restricts the flow of water through the radiator slightly. This is important in the whole scheme of how the radiator cools the water. Without a thermostat in, the water flows too quickly through the radiator, and doesn't have enough time to exchange the heat to the air outside the radiator before it flows back into the rest of the system, picking up even more heat.
Were these guys correct? I can't say, but I've never run my systems without a thermostat, that's been tested and verified working properly, or replaced new out of the box. Only overheats I've ever had were the two times the water-pump belt broke on me while driving in the 4Runner.
Well, one time it happened to a "friend" I let borrow the truck, and he just drove it till it was way overheated, stopped to let it cool, drove it until it was overheated, etc, until he got it back to my place. Cracked the head. There was a new belt in the back, and tools to install it, but he cracked the head. Some friend...
The second time, many years later, I just pulled over, let it cool, replaced the belt and drove home, no problems.

The little piece on the bottom of my 4Runner's fan shroud vanished somehow, so I cut a piece of tin to fit, and screwed it in. Works great.

Finally, are you sure the radiators, including the AC condenser radiator, aren't clogged with bugs, mud, etc? A quick back-flush through the radiators with an airgun on a compressor, or even a good nozzle on a water hose, will make sure the radiators are clear. Makes sure the air can flow freely, allowing a good exchange of heat out of the water of the cooling system, to the air flowing through the main engine radiator. Pretty important. Also, make sure the fins on the radiator aren't bent over, blocking the air flow.

Just my experiences...
Pat☺

 

You only suspect bad HG IF, and only IF:
1) You have milkshake coolant, AND/OR
2) You're losing coolant excessively.

You could lose coolant if:
1) It enters cylinders and is getting burned. / vaporized, OR
2) if bad GH allows exhaust gas into cooling system, pressurizing it, and pushing coolant out to and through the overflow reservoir. Overflow vaporizes while engine is running / engine compartment is hot so it might not leave a trace. I tested this and eliminated doubt about it by old-school glove method. here: https://www.yotatech.com/forums/f116.../#post52438581

 

Radiator(s) are clean and free of debris of any sort. When I was flushing it I did hit it with pressure and everything seemed free and clear. I'll have to recheck the shroud specifically for any damage.
I repaired the cooling fan. The blade assembly had simply unscrewed from the motor axle. I put it back and straight wired it in for testing. Can't say that it contributes anything towards this situation. If anyone can find a wiring diagram that shows this fan and its control wiring I'd love to see it! I do want to test/fix that.
Thermostat. The car ran at least 8 years without the t'stat without showing any obvious effects. It never gets below 70 degrees here so I don't really feel its needed. It has one now and the car heats up quicker than before as to be expected. Dash gauge starts rising immediately when engine is started.
I might add that nowadays I only drive maybe 2k miles/year. Much of that at not much more than idle speed around the neighborhood. Maybe one trip to town (5-6m each way) once a month. This seemed to start abruptly a couple of months ago. Can't even make it to town (gas station - haha) now. With no more driving than that its difficult to evaluate if its losing any water or some went to the overflow tank, etc.

 

The electric fan will only run if your A/C works and is turned on.
as others have stated, the fan shroud is important, also you should check the mechanical fan clutch. with the engine off spin the fan by hand, it should come to a stop quickly. give it a wiggle, there should be little or no play/wobble.
If everything looks good you should really evaluate coolant loss. make sure everything is topped off and all the air is burped out of the system then get or rent a cooling system pressure tester and see how long it will hold 15 psi.
If the pressure drops quickly (just a few minutes) you can pull the spark plugs and start looking for where the coolant is going, either on the ground or into the cylinders, possibly into the oil pan or exhaust or intake, even into the cab from a leaking heater core.
let us know what you find.

 

Thanks all.