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Discussion Starter · #1 ·
Hello,
Over the weekend I was driving and the serpentine belt broke unbeknownst to me. When this happened i lost heat, power steering, and the alternator. I continued to drive without for several miles. I replaced the belt and when I did the car continued to have no heat. initial thought was the thermostat was stuck or burnt up from not having circulation. When I started driving the temperature gauge shot all the way up to high. Jump ahead to having it in a garage and working on it, the thermostat seemed to work fine after driving it a bit, the heat turned on and the temperature gauge ran normal. Now whenever I start it in order to get heat I have to rev the engine for a few seconds for heat to turn on. Today when I started it I revved it and got heat but as soon as I stopped the heat gradually went away. Could this be a thermostat issue or is it something more serious like a water pump or a head gasket?
 

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Your Humble Administrator
2008 RAV4 Limited V6
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You should have pulled over and stopped the engine the moment you lost power steering and got the alternator light. You could have overheated the engine. In any event it sounds like a bad water pump to me.
 

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it in order to get heat I have to rev the engine for a few seconds for heat to turn on
This is also a classic sign of low coolant level. If the engine got too hot when the belt broke it may have boiled off some of the coolant and could now have an air bubble trapped in the cooling system.

-Saturday
 

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Check your coolant level and let us know before we run thru all the other possibilities.
 

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There usually is a bleeder port near the thermostat housing to allow all the air out.
As Junebug said you should have stopped as soon as the possible after the belt broke to avoid engine damage such as a blown head gasket.

And continuing the drive with low coolant level WILL do damage. You need to be much more concerned with your engine's "comfort" than yours.

I had the serpentine belt fail on my '01 F-250 while towing my trailer on I-495 around Boston recently. First my alternator light came on, then I lost power steering and power brakes so I knew what happened. Losing A/C was the least of my worries. Unfortunately I had just passed an exit and had to drive 6 miles to the next one. The temperature gauge stayed normal for a few miles but was into the red by the time I was able to exit. After letting it cool off the reservoir level was normal. I carry a spare belt and was able to change it and get home that night with no engine problems.
 

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When the thermostat was replaced was the cooling system purged to get rid of air which would have gotten into the system? Air in cooling systems tends to get into the heater coil and be trapped since that is the highest point in the system, and interfere with or even stop the circulation of heated coolant in the coil.
 

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Discussion Starter · #7 ·
The thermostat hasn't been replaced yet. I did check the antifreeze level and it was severely low. I added some and it still did not seem to fix the issue. With the vehicle running I felt the top hose running to the radiator and it was still cold. I also noticed that the vehicle seems to be running at a cooler temperature than normal. Is this a sign of the thermostat being stuck open? Also, where is the bleeder located to purge the system of air? Any help is greatly appreciated!
 

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With the vehicle running I felt the top hose running to the radiator and it was still cold.
On a warm engine, a cold radiator hose is an empty radiator hose. When you added coolant was that directly into the radiator or into the coolant recovery tank?

-Saturday
 

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Discussion Starter · #9 ·
At first it was in the overflow tank, however, today I added some directly to the radiator itself. The cold radiator hose problem does not seem to be a problem any longer as i have been checking it after driving and it is hot to the touch. What should my next step be to diagnose the problem if there is even a problem left? After driving it the past couple days it seems to be running normal...temperature and heat seem to be maintaining at a normal level.
 

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At first it was in the overflow tank, however, today I added some directly to the radiator itself.
IMO the only issue ever was low coolant. And until you filled the radiator it was still low. Just keep checking the overflow tank for proper level and the system should be good now.
 

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Sounds like you are on the right track. Continue to keep an eye on the coolant level. It is hardly uncommon for older vehicles to loose a little coolant as they age... I drove an old truck for years that always a green drip hanging off the bottom of the block. But it didn't leave spots on the drive and only actually lost about a pint of antifreeze per year.

-Saturday
 

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Discussion Starter · #12 ·
Hello all,

After monitoring for a few weeks after adding antifreeze to the radiator everything seems to be fine. The heat is working without revving and the level of antifreeze has not dropped.

Thank you for all the help!
 
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