Who replaced the thermostat? The best choice is to buy an actual OEM part from a dealer. (It has a jiggle piece that lets air escape.) That way you are sure to get the air venting type of thermostat along with reliability. ... Also, it must be installed with the correct orientation in the housing. ... It must be installed with the correct side UP.

 

Who replaced the thermostat? The best choice is to buy an actual OEM part from a dealer. (It has a jiggle piece that lets air escape) That way you are sure to get the air venting type of thermostat along with reliability. ... Also, it must be installed with the correct orientation in the housing. ... It must be installed with the correct side UP.

That was a previous problem. I ordered the toyota standard thermostat that has that jiggle piece, and it came with the gasket as you described. The old therm didn't have it at all. Before changing the therm, that lower hose was cold while upper radiator hose was hot. Now both hoses get hot.

Could I still have air in the coolant system? Car rides fine, with no hesitation. Onpy problem now is, the cooling fans do not come on without the AC turned on.

 

Removing the fan switch and fans come on only proves out the electrical and relay - not the switch.

I suspect you have a bad switch.

 

Good God, I was contemplating on replacing both fans, lol. That switch came from a junkyard, and even that switch didn't work. It looked like it was recently changed out. I will buy one from an auto parts store this time. Gonn have to drain coolant from radiator again. I have seen in some vids where they recommend taking the skid plate off to get to the switch. All I did was take the fan that was over it, off and proceeded to unscrew the switch with a 19 wrench.

So, if it turns out not to be the swit h after this, what else could it be?

 

So you are saying that even when the temperature gauge on the dash panel registers high ... above the middle ... the main radiator fan does not come on?

 

Yes that is the problem as of yet.

 

Do you have a multi-meter? That switch can be tested for continuity. If the coolant temperature is below 203 degrees F, that switch should be closed ... very low resistance. Above 203F, it is open ... very high resistance.

 

The switch is normally closed - current flows. This is a fail safe feature. The green "gunk" would have simulated the fan on position if it were having an effect of no current flowing.

Make sure you clean the connector contacts before hooking up the new switch. You can use an electrical cleaner spray.

 

I dont know what it is, but I replaced the switch and those fans still didn't come on. Is it a good thing if the top radiator hose is shrinking?

 

I'd check to see if the radiator has some cloggage or something, for the hose collapse.

For the switch, check RockAuto's catalog under your car -> your engine -> Electrical - Switch and Relay -> Radiator Fan Switch

I've had good luck (not a single failure in tens of installs over the past five years) with the Beck/Arnley offerings. If there is a different part for US-built vs Japan-built, check your VIN...US-built starts with 4T and Japan-built starts with JT.

I just realized, I've only ever replaced these on 4-cyls...never seen a V6 unit fail. I may be grasping at straws here - and not to go OT too much - but I seem to remember several discussions about how the 1MZ warms up slower than the 5S, not sure if related (or if the 5S runs hotter, etc.).

 

Is it possible that the radiator can clog up, causing the radiator fan switch to fail? The bottom coolant hose gets hot too, which means the coolant is circulating.

 

My solution in any regard is to purchase a brand new radiator and never look back.


The critical item here that you are trying NOT to ruin besides your Engine is the Automatic Transmission what has Cooling Lines going to the bottom Plastic Tank area of the Radiator.


Should temperatures get really hot and you get stuck in heavy traffic with a clogged UP radiator, you just might over-heat the Automatic Transmission! Not a Good thing!

 

You need to replace the number 1 fan relay. Cheap plug n play- joy. You can swap the number 1 and number 2 fan relays to prove the number 1 is bad, since after the swap, your fans will work like they should. Since the AC makes the fans come on, you know its relay is good. Keep that relay and replace both of them and have a spare for 10 years from now when this happens again. Don't laugh- Toyotas have long lives.

 

Both fans come on when switch connector is removed.How is that the relays??

 

Yes, Complete Cooling System Flush and then, purchase a Brand NEW Radiator.

Depending on how old that Radiator plus stresses of going higher Temperatures when in fact that Radiator has been clogged then, it is just a matter of time that the upper and perhaps lower PLASTIC Tank will develop stress cracks.

 

I just checked my oil dip stick and the dang thing had no oil in it. It is possible that the oil burned drastically and is also helping with the engine overheating.

All of you guys been laughing this whole time, lol. I replaced the radiator over a year ago. My dad is a firm believer that the water pump is failing and yet the coolant is still circulating.

 

The relays are controlled by the switch which senses temperature, turning them on and off as needed. They are needed while idling at the stoplight where you've been overheating. Take 15 minutes in the driveway to replace the less than $20 number 1 relay. You don't need to replace the radiator. I had this very problem and eliminated it by replacing the faulty fan relay. Your fans work. Your switch works. Your relay doesn't. Save your weekend for fun, not for overhauling, unless you already cooked the engine and blew a head gasket. Good luck.

 

I have to agree!:smile:


OP (Joseph) did post that he performed a Coolant Flush so, perhaps the radiator might be okay?:wink:


Go slow and one item at a time. Just don't take a long trip!:laugh:

 

Hey guys, i just replaced the radiator. Now I am suspecting the switch, and the wiring. The relay, amd RDI and CDS fuses are fine, not blown. It has gotten better since trying to drive before required Ac and defrosters and full heat blast. Now it is just AC and heat full blast. The engine isnt seized, but the radiator is still releasing bubbles. I switched over to full blast cold, and more bubbles were coming out of the radiator. It revved higher and even more bubbles came out.

The OEM thermostat must be working because of it having the small pin in it and lower hose heating up. Coolant is circulating because water pump.

I changed out the oil and its filter after seeing no oil on the dipstick.

Like I said, I am now suspecting that switch and the wiring. Going to replace the switch today and see what it does, and it isn't coming from a junkyard, lol

 

but the radiator is still releasing bubbles. I switched over to full blast cold, and more bubbles were coming out of the radiator. It revved higher and even more bubbles came out.

You probably have a cracked head from the over heat. If you have no oil in coolant and no coolant in oil and no coolant in cylinder then I doubt head gasket.

 

Hey guys, just replaced the auxillary fan switch, and have nothing else to trouble shoot. The cooling fans still do not come on. I am still stuck driving with the AC on with full blast heat. What else could there be? Whenever trying to drive with the AC off, the car accelerates very well. Is there supposed to be a specific direction the cooling fan switch should be on the radiator?

Could it possibly be the engine coolant temp senser? You know the one that usually has the green electrical on top. Should be the bigger temp sensor next to the smaller temp sensor, just on the side the engine, on the water neck.

Also, is there a chance that the wiring from the switch can go bad too? The relays are not the problem.

 

Please clarify ...
Do the fans come on under any circumstance?
Have you replaced any of the fan relays?
The No. 2 and No. 3 Fan Relay are identical and can be inter-changed. The No. 1 Fan Relay is unique and cannot be interchanged.
... There is also a Main Engine Relay that is unique.
... Is there another similar year Camry nearby that you could temporarily borrow a No. 1 Fan Relay ... just for diagnostic purposes?
Also, do you have the V6 engine?

 

I have a 4 cyl. I have replaced all of the relay fuses for the fans, including the cds and rdi fuses for the cooling fans. I read up that if the coolant temp sensor is bad, the computer will fail to get a reading, and car will over heat. Both fans turn on, when plug to radiator, cooling fan switch is unplugged.

Im puzzled, do I let the car complete heating cycles with the the plug on the coolant temp sensor, unplugged. I hope to god it isn't that small sensor next to the coolant temp sensor. That thing is so easy to break.

 

The ECU Temperature sensor adjusts fuel flow to the injectors and
is not directly associated with the radiator or condenser fans.
The two wire thermal switch that is located at the lower, passenger side of the radiator would be responsible for the radiator fan not turning on as the engine coolant warms up. This switch is called 'Temperature Switch No. 1'.
It would be necessary to drain the coolant from the bottom radiator wing-nut valve, and then disconnect the electrical connector, and unscrew Temp Switch No. 1, and replace it with another identical switch. If you are not inclined to purchase a new switch, then check with your local salvage yard.

 

Is there a certain why the radiator fan switch goes in there. I have it in the radiator now, which is a newly bought sensor, and the cooling fans still fail to turn on. I drive with the ac on. I turned the switch too much on the last rad, and stripped the tread.

 

If the No. 1 Temp Switch is new, the part to suspect as a problem is the No. 1 Fan Relay. This relay is located in the relay box under the hood, next to the driver side fender. Have you replaced this one yet? Be sure it is the No. 1 Fan Relay.

 

Yes I replaced it already. You know, it could just be that wire going to the radiator fan switch itself. The fans do come on after that two wire wiring is unplugged, from either end.

 

When the coolant reaches 203F, that switch is supposed to pop open and the radiator fan turns on. It is not supposed to turn on until the coolant warms up, unless that is, you switch on the AC.
So are you completely sure that it is not working?

 

Yes, unless I turn on the AC, the fans do not spin and cool the engine. When I take it for a drive, the temp needle seems to climb near 8/10 of the gauge, but when braking and stopped at say, a red light, the temp dwindles fast to the middle of the gauge. All of this is when the AC is turned on. I would like to drive without the ac on. Thr car rides better with it off, and fuel doesn't get chugged as fast.

I like how I am not holding up traffic at red light stops with the AC off. That car will accelerate, but I am not a street racer, lol.

Im at a loss, but the car isn't undriveable...

 

Have you ever replaced the radiator cap? After so many years, they lose the ability to seal, and when that occurs, the coolant is not able to get hot enough. The cap must seal. Buy a new cap, if yours is original or old.

 

I will try this. I tried unplugging the coolant temp sensor, and car would not start, lol. So that sensor is good. The smaller sensor next to it is okay too since it just senses the engine temp.

I was told by an exp'd mech that the radiator cap was still good. Example being, the coolant in the radiator does heat up. When the car is shut off, the radiator hose shrinks creating that vacuum in the coolant system.

Are you sure there isn't some calibration that I missed with the cooling fan switch. Should I turn it into the radiator until it stops turning. It looked like it wouldn't go in anymore, but kept turning.

 

I tried unplugging the coolant temp sensor, and car would not start, lol.

OK, I'm confused. Few things:


1. Did you replace the thermo fan switch (radiator fan switch) at the bottom, passenger side of the radiator with a brand-new, reputable-brand part?



2. That fan switch looks very similar to the two up top. You tried unplugging the engine coolant temperature (ECT) sender that feeds data to the ECU. Car wouldn't start, that's the expected behavior. If it was bad, more than likely the car would run rough and get poor fuel economy after warming up. The other sender there (one wire) feeds the gauge on your cluster. If it goes bad, the gauge won't work properly.


3. Can you clear up in one post what's happening? If it's just the fans not turning on, but they turn on when you unplug the switch at the bottom of the rad or have to turn on A/C to keep them running, then replace the fan switch. Ignore the ECT senders up top by the head as they have no direct effect on the fans turning on/off. Also, when I say "reputable-brand," I mean something like Airtex/Wells, Beck/Arnley, etc. Stay away from "OES Genuine," Stamdard Motor Products "T-series," eBay sensors, and used parts.

 

Is there coolant about half way in the fender reservoir bottle? The cap should allow the reservoir bottle to top off the radiator coolant.
Tightening the switch some more is one possibility. It should not be loose, but that is something to be cautious with. I would suggest taking it out completely, and wrapping a layer of white Teflon sealant tape around the lower threads. A trick to avoid cross-threading is to insert it so as to start it, applying light pressure, and twist backwards until you sense a 'click', which indicates that the threads have begun to mate, at which point you begin twisting in the clock-wise direction, knowing that the threads are straight and have no problem. ... Try out with any threaded object/assembly.

 

The last mistake with the replaced radiator, was that I turned the switch too far and ruined the tread. I will try turning until it stops and see what happens. O can at least drive the car, so getting a radiator cap isn't an issue. Could I possibly find the wiring that goes to the switch, on ebay too.

I have noticed not one change with that coolant overflow tank reservoir since replacing the coolant after the flush. after I filled it up halfway, it stayed stagnant.

 

With the engine cool, remove the radiator cap and see if the water is at the neck of the radiator cap opening ... As I recall, there is a small opening within the neck, where a rubber hose goes to the reservoir bottle. If the coolant level in the radiator is not right up to that tube opening, then there is a problem someplace ... maybe your radiator cap is not two-way, like it should be. Sometimes, it is best to get a cap from the dealer, just for reliability/correctness.
I find it unlikely that there is a wiring problem.
Have you noticed any leakage or coolant in the vicinity of the water pump? The water pump has a diagnostic 'weep hole' which is designed to leak water prior to a pump bearing failure. ... that is something that requires a flashlight and some looking around.

 

The water pump is fine, or else the coolant wouldnt be circulating. I had it replaced a couple of years ago. I haven't noticed any leakage of coolant. Still haven't tries to tighten the coolant fan switch yet.

I am still surprised at how easy it is to get to it. I was told to take the slid plate off by 1A auto, lol...

 

The water pump is fine, or else the coolant wouldnt be circulating. I had it replaced a couple of years ago. I haven't noticed any leakage of coolant. Still haven't tries to tighten the coolant fan switch yet.

I am still surprised at how easy it is to get to it. I was told to take the slid plate off by 1A auto, lol...

dc_98_cam posted something that is sound. A water pump will still WORK and have Coolant Circulating while it leaks at the "weep hole." When bearings are about to fail or have failed, usually the Pump will leak while the car is parked and not running.


So, you looked at the Passenger side and you don't see coolant, correct?:|

 

Okay,


Good luck with the Radiator and hopefully you can get another one and fix the Fan Switch tightening issue.

 

The one question is, with the engine cold, does the coolant level come all the way up to the top of the filler neck, or is the level someplace lower down in the radiator?
Wait until it cools down and see where the coolant level is. Your mentioning of a collapsed hose due to a vacuum doesn't sound right. A correctly working radiator cap should allow air bubbles out, and coolant from the reservoir bottle in. Ordinarily, you can check the radiator coolant level by just keeping an eye on the level in the reservoir bottle. However, you have to have the correct radiator cap.
... Also, if one of the two wires going to the lower radiator thermal switch was broken, the radiator fan would come on immediately after the engine started ... not what it is supposed to do (with the AC off).

 

The coolant is not lower than what it should be in the radiator. The level of it has not changed in the reservoir.

The radiator hose does not shrink while the car is running. I only notice this when the car is cooling down after a while of being off. I have taken the radiator cap off and the radiator hose sprung back like it wasn't shrunk. I might not have let all the air bubbles out yet either. The coolant has a tendency to go down after releasing air bubbles too. Is it a good idea to floor the accelerator to let loose alot of bubbles?

Thanks for clarifying the wiring on the cooling fan switch.

 

never ever. Put on that temp or coolant sensor without a washer. The lady at advance auto told me just put it on, and that it would affect anything. Yeah, she was about to go on her smokinh break and couldn't be bothered to help find a small washer...