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No heat/loud squeak

6K views 27 replies 6 participants last post by  leon r 
#1 ·
Hey folks, I've been reading a lot here and am totally appreciative of all those who post and respond helping each other out. I have yet to read a car guy/tough guy argument!! :laugh Anyway, I have a couple problems and I'm asking for advice or tips or answers.

Problem #1: LOUD belt squeak when starting. Only when the AC or heat is on mostly but it has happened with neither on. From what I've read it could be the AC compressor belt or clutch or the compressor itself. Any tips or suggestions? But then I am wondering why would it happen with no AC on. I just bought the Rav and the AC did not work at all. I charged it and it works great.

Problem #2: NO HEAT!!! The heater core hoses are not hot. One is mildly warm and the other not warm at all. I plan on getting a flush as step one soon but just wondering that since one hose does get warm does that mean the heater core works or can it be bad and still put out a bit of warm?

As you can tell I don't know **** about working on cars. What I do know I've learned from reading this forum. I just bought the
 
#2 ·
I had that problem some years ago - the problem was the thermostat, which was stuck open. The way that it was designed that problem directed nearly all of the coolant to the radiator. That also resulted in the temp. gauge reading abnormally cold much of the time. Yet the problem which you are describing could be a heat control which is not working properly (is the dash climate control wire attached to the control valve, for example?) and prevents coolant from flowing through the heater core.
 
#6 ·
If your RAV's coolant temperature gauge shows abnormally cold temperatures after the engine should have warmed up (driving it on the highway, for example) then that would be one clue that the thermostat is the problem. Unfortunately actually checking the thermostat itself involves removing it from the cooling system (possibly difficult access) and examining it visually - it should be closed at room temperature. If it is open at that temperature then it is defective. Checking the heating control cable to see whether it is connected to the heater core regulator valve - it is under the dash work but you may be able to see the connection at the heater core control valve without contorting yourself too much. If the cable is connected there then turn the heat control on the dash back and forth and see whether the cable moves the valve - it should, if the connections are OK. I am assuming that your system is manually activated without my actually knowing. Perhaps another forum member knows for certain.
 
#4 ·
Welcome,
Try removing the belt that drives the ac compressor and alternator, see if it still makes the sound, if it does it could be the water pump, you don't mention any overheating issues but the pump could be on its way out.
Have you checked the belt tension on the power steering pump?
Before getting under the car, start it and pull the steering hard, see if the squeal gets worse.
Let us know what you find
Good luck
 
#12 ·
When I cut the wheel all the way a belt noise comes that is not there otherwise. WHen the squeal at startup happens I don't think it could get any louder, wheel turned or otherwise.:oops:

The PS belt doesn't seem loose to me though. Not nearly as loose as the drive belt.
 
#5 ·
VIDEO ADDED!!

Ok so I checked the pump drive belt and it seems tight. But the generator drive belt seems loose to me. I took video, can anyone take a look and weigh in on whether they think it should be tighter? Keep in mind when I am moving the belt I am using minimal effort.

Thanks!!

 
#7 ·
To me the engine temp seems ok. The gauge is functional and is usually about 1/4 to 1/3 of the way up. When sitting at an idle it will rise to about half way and the cooling fan will come on. Temp seems to remain steady at that level. Does that sound like it's abnormally cool? It isn't for the other cars I've owned but I have never owned a Japanese car older than 4 years old. Until this Rav of course.

And yeah, your're right. Checking the thermostat is beyond my current mechanical abilities. Perhaps someday??
 
#8 ·
I don't know what your temperature gauge is supposed to show when the thermostat is working properly but from your description the thermostat seems to be OK.


Then if there isn't a problem with the heater core valve control cable being disconnected or broken there may be something which is blocking the flow of coolant through the heater core. Does the coolant show any signs of rust, and has it been changed according to Owner's Manual recommendations? Perhaps as you suggested at the start a cooling system flush with an approved cleaner may solve the problem.
 
#9 ·
That's my plan is do either get a flush done or do it myself. I have never done it on any car but never needed to either. But yes I do think the coolant looks pretty crappy.

So just changing the coolant is not a flush, how would I go about flushing it myself?? Or perhaps could you point me in the right direction of somewhere I could find a how to? I've searched but haven't found an instructional thread.
 
#10 ·
First off your belt looks too slack, it ought to be tight, very minimal deflection, maybe a quarter inch or so in each direction, it's very easy to tighten, the adjuster is up there in front of the alternator.
The thermostat is easy to do, follow the bottom hose up, there are two 10mm nuts, loosen them and pull it away, the thermostat is inside. Get a new thermostat and rubber seal/ gasket first, rock auto have many to choose from.
With the stat out you can reverse flush, stick a hose pipe up the bottom hose, water should run through and out where the thermostat sits.
Plain water is fine, run it until it comes out clean then make sure you add anti freeze when you refill and if your water is hard then use distiller/ionised water, or pure rainwater will suffice so long as it's filtered first.
Otherwise remove the top hose and stick the hose in there but you need the thermostat out anyway since it will be cold and therefore closed.
The temp gauge from what you say sounds about right therefore I doubt poor circulation caused by a broken water pump is the cause of your lack of heat, unless it's so cold there already that your engine is running cold!! Somehow I doubt that....yet!
More likely the thermostat is stuck open, hence my suggestion you got a new one anyway after flushing.
Follow Blogson's suggestions too, you'll find the cause soon enough.
 
#13 ·
I am away from home and don't have my RAV with me to look at but you need to loosen the alternator pivot bolt first then tighten the adjuster.
I have just worked on a different car here and it had one hell of a screech on start up, it was the alternator belt that was too loose, the alternator works hardest then and therefore is harder to turn so the belt slips if it's loose.
If you get another squeal when you turn the wheels to full lock then the power steering belt is also loose. If the noise is like a low pitched shhhhhhh then it's the valving in the rack relieving pressure, it's supposed to do this.
 
#14 ·
Thanks for the help. I'm going to tighten the alt. belt and do a coolant flush this weekend. I have a feeling that alt. belt is the cause of the squeal after seeing how loose it is.
But one thing I'm wondering is that if it is the alt. belt, why would the AC being on have to do with it? Anyone??
 
#15 ·
That's the easiest of your questions yet.... the alternator belt and the air con belt are one of the same.
As I said, the alternator puts a load on the belt and so does the air con compressor when the a/c is switched on.
Check the condition of the belt and if you see any cracks in the ribbed side replace it. Its best to remove it and flip it inside out to do this. If its old its more likely to squeal anyway as it looses grip.
 
#16 ·
Well... kinda feel stupid now. Haha. But I'm new to working on cars and learning.. a ton in just a matter of a few days. Thanks for the help and I'll probably have more questions this weekend.

WAIT... I just thought of one. If I do the coolant flush and still no heat, could I then do a heater core flush without doing the coolant flush again? I ask because I would rather not do a core flush unless I find it necessary since I'm new to working on cars. I don't want ti eff anything up unless i have to!!
 
#17 ·
The coolant flows through the engine, into the radiator and into the heater matrix which is a small radiator, so you will be flushing the entire system. Make sure you set the heater control on the dash to hot to open the valve.
Look at the thermostat when you remove it, hopefully you are fitting a new one, but you are trying to determine if the old one is stuck open and if that is the reason you can't get the heater to produce heat.
They should look similar, if it's stuck open then you will see the spring is compressed.
You can test a thermostat by puting it in a saucepan and heating it, you'll see it opening if it's okay. It's okay to do this to the new one as well, I do, to ensure it's working okay.
If flushing and a new thermostat does not resolve the problem then it is likely the water valve that let's the hot water flow to the heater matrix may be stuck closed. Personally i haven't experienced this on a RAV though.
It's okay to refill the system with plain water while you determine if you have solved your problem but if you have then let it cool and drain the water out through the petcock (a tap at the bottom right corner of the radiator when viewed from looking under the hood) and refill with anti freeze and distilled or filtered rain water ( you dont want hard deposits in the system)
Good luck.
 
#28 ·
The coolant flows through the engine, into the radiator and into the heater matrix which is a small radiator, so you will be flushing the entire system. Make sure you set the heater control on the dash to hot to open the valve.

Are you sure that heater controller actually restricts the coolant flow in a Rav4?


The only car I saw do this was at Triumph TR7 and I am sure that some other cars do this. But most cars allow 100% coolant go through the heater core 100% of the time and use a "blend door" to achieve desired temperature. Can someone please confirm which system is used on Rav4?


Looking at the factory temperature gauge to diagnose your thermostat is not very effective. Those gauges rarely have the accuracy to tell you +/- 20* deviation from the "normal". Instead, you should ether use an infrared thermometer or use OBD2 scanner to tell you actual, measured temperature.
 
#18 ·
Ok so I did the coolant flush and it definitely needed it. But now the hoses into the firewall that go to the heater core: One is HOT and one is cold. Before I jump to the conclusion that the heater core is bad... how would I go about doing just a heater core flush?

It has been mentioned to change the thermostat. I bought a new thermostat but forgot to buy a new gasket. But worse than that... I have no f#$%ing clue where the thermostat is or how to change it!! No matter what I search I cannot find a pic or a video. (I am a very visual learner)

Anyone help?? Thanks!!
 
#20 ·
Without removing the thermostat you won't have flushed the engine block, the 'stat' would have been closed and will have prevented water from flowing through the engine and probably the heater.
Did you put the heater on hot to open the valve?
Can you hear/feel the hot lever opening the valve?
If the valve is stuck closed you will have one hot hose going into the heater and one cold where no hot water is comming out.
If you want to only flush the heater matrix (I advise you remove the stat and flush the engine properly) and as you have identified which pipe going into the firewall is hot and which is cold then simply disconnect the rubber hoses from the aluminium pipes and flush, don't put too much pressure through, you only want the water to flow through gently.
If it doesn't flow then the valve is probably stuck closed, this is more likely than the entire heater matrix blocked, but that is a possibility.
I explained previously to follow the bottom hose from the radiator to the engine, remove two 10mm nuts, thats where the thermostat is, inside the housing at the end of the hose. Get a new rubber gasket first and do what I said to test the new and especially the old thermostat.
Go over my previous replies again before you have another go.
Did you tighten the belt, has it stopped squealing?
 
#21 ·
Yeah I can feel the hot lever moving and changing from hot to cold. There doesn't seem to be any problem there, from what I am seeing anyway. I will give the thermostat change a try and then do the flush.

On the belt subject... YES!! I tightened the belt and squeal is completely gone so far. I was planning on letting you know that and say thanks.

I'll keep updating as I go.
 
#22 ·
Well... I've got heat!!! I didn't end up changing the thermostat (yet) but i did a heater core flush. That combined with the coolant flush did the trick. At least for now. It's not suuuper hot heat by any means and the hose coming out of the core is still only warm, not hot. But for now, it's ok.

So... I have some heat and no more squeak!

But... today the P0401 code popped up. I read it's an EGR problem. Does anyone have an opinion on whether the coolant flush is related somehow? It's an odd coincidence if not.
 
#23 ·
EGR and coolant are in no way related, maybe you flushed water Over the EGR vsv which is down the back of the engine, leave it to dry out or spray WD40 if you can find it (see sticky at the top of this forum for pics) or maybe you dislodged something like a vacuum pipe to the EGR modulator or EGR valve, both are close to the heater inlet/outlet's.
Glad you have heat now but please, since it sounds like you have some sludge in there, buy a can of coolant flush, add it, run it with the heater on, then remove the thermostat, flush the entire system with the heater valve on hot and finally refill with anti freeze mixture before it gets cold there.
 
#24 ·
maybe you dislodged something like a vacuum pipe to the EGR modulator or EGR valve, both are close to the heater inlet/outlet's.
Now that you mentioned it I did bang on the EGR modulator pretty hard by accident trying to pull off the heater core hose. Hope I didn't kill it. So how would I know if I damaged it, other than the check engine light? (I cleared the code and am waiting for it to come back.)

I am going to try to do the thermostat this weekend. And I do want to thank you again for all of your help. You saved me a lot of money, mate!!
:cheers:
 
#25 ·
Gład to hear your going to try and flush again, if you made progress already then another flush could fix it for good, I mentioned adding something, you can buy an additive that should loosen all the sludge in there, add it, run it and then flush it. (Instructions on can!)
Now the EGR...... The modulator - that's the round plastic thing on top of the inlet manifold, hitting it probably won't hurt it unless something broke off, it's a vacuum operated diaphragm that modulates the pull on the VSV, I can't put my hand on the test stuff I found when I tested mine right now but the two pipes on the right suck in different stages and lift the diaphragm inside and divert vacuum to the VSV, which in turn diverts vacuum to the EGR valve.
You could unplug the vacuum line that runs from the modulator (on the left side) to the VSV with the engine running and see if you can feel vacuum on the modulator port, if you do then it's probably ok. Put the pipe back on.
Next, with the engine running, place you hand on the EGR valve and feel underneath it, blip the throttle and you should feel the EGR valve lift and open, if it does then the modulator, VSV and the EGR valve are probably ok but the EGR valve may be blocked with sludge, remove and inspect it, if there's sludge then you may need to remove the throttle body too and clean it and the inlet manifold out.
If the EGR VSV is not working then there is a ton of info on here about how to replace it, I wrote a bit a few years back when I moved mine to the firewall by reaching down from the top of the engine but I saw something here only yesterday with pics on how to do it, basically, if you can't reach it then just disconnect it, leave it where it is and fit a new one on the firewall, but that as they say is another story that for your sake I hope you won't need to read.....
 
#26 ·
Just thought I would update this thread with my results. I had the thermostat replaced and the heat is nice and toasty!!

I'm updating because I hate when people have a problem, get help with the problem but then never return to say whether or not the problem got solved.
I was almost one of those twits but here I am updating!! Better late than never!!

Thanks for all the help!!
 
#27 ·
Thank you for the update! Sounds like the old thermostat was stuck open after all.
 
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