My 2007 es350 77k miles. Heater starts to get warm and then it blows cold air. What could cause this. Any ideas.

 

I read something on here about the same problem and it ended up being a water pump problem, I'm not 100% sure tho, maybe make an appointment to have it looked at. I'll try and find that thread and post it.

 

If your antifreeze in the radiator & overflow tank aren't 100% full, what you described can occur. You may also experience overheating, which can & will destroy your engine. A leaking water pump can cause this, or a leaky radiator.

If you are unsure what to do, immediately seek a knowledgeable person to assist you, like your nearest dealer.

You may be on thin ice here--don't fall in!

 

I am having a similar problem with my 2007 es350, it looks like when the car is running it starts hot air but eventually it blows clod air. Similary when I have stopped the car a signal or traffic cold air starts blowing. couple of times I did try the air intake to change from outside to inside but still the problem exist but some times it blows so hot air that I turn off the heater, can any one suggest what is the fix for this issue, did anyone face the same issue and how it was fixed.

 

As mentioned.......check the coolant level ASAP. If the coolant level is not between the L and F marks on the coolant tank (or lower, or not visible in the tank) then you've had a loss of coolant. In the case where the heater output flunctuates, or blows cold air when it shouldn't, then chances are the coolant level is really low. If it's really low do not drive the car until you add coolant, then get the source of the leak repaired. Another indication of a really low coolant level is a coolant temperature gauge that is not responding correctly. If the coolant temp gauge does not get up to about mid-range after about ten minutes of driving (reading low) then that can be another indication of a low coolant level. Did you ever notice the temp gauge needle in the HOT zone even for a short time, anytime in the past?
Also as mentioned the coolant pump on these cars has been the source of coolant leaks on many occasions and is a known issue. There is a TSB "L-SB-0091-11" that has the procedure for inspecting the coolant pump.

 

Thanks Oldgrump for suggestion. I did check and there was no coolant in the tank, so I filled it with Prestone 50-50. I don't think the issue is fixed yet as I started heater only once since then and I still feel the air was not warm enough at the constant set 72 degree

I am trying to understand the logic between the engine coolant and the heater as I remember in previous old car I rarely filled any coolant in the coolant reserviour and I use to feel the heat not sure may be I use to keep it in Max all the time. Surprisingly my other car has also no coolant in its tanks, honestly I never checked till lately and its heater work perfectly and as per your question the temp gauge never went above the center line of C & H in any of the cars including my current ES.

Is there any heating coil that throws hot air in the car that might be going bad??

 

If there was no visible coolant in the coolant tank and because you still don't appear to be getting heat then I'll bet that the cooling system is still not close to being full. You need to add coolant (ENGINE COOL) to bring the coolant right up to the radiator fill port (in other words the radiator has to full as well). The radiator cap is hidden under the forward engine compartment cover (which is retained with several "push to remove" fasteners). Make a note on how much coolant/water you have to add to the radiator to fill it. You appear to have lost a large amount of coolant and you ABSOLUTELY have to find the source of the leak. IF you haven't seen coolant dripping, or haven't smelled it, then the leak is probably a very small/slow leak. The coolant pump shaft seal has been known to leak on these cars, as I mentioned above.
Unless there is a AC/heater control module or other electrical problem that is causing an operating issue with one or more air diverter doors (controls the air temperature) and as that there is always coolant flowing through the heater core (assuming the system has enough coolant and the heater core is not plugged) when the engine is running, you should be able to get heat.
Once the leak has been found and fixed, I suggest that you use the recommended Toyota coolant (it's pink/red in color).
Remember people.......periodically check/monitor the coolant level! It's really important.

 

Thanks Oldgrump, I did not know there is toyota specific coolant, I used Prestone 50-50. As suggested I will check the radiator level also. the cover has too many pop up screws and I damaged one edge and one screw while popping up the screws to fill the coolant, I did not check the radiator level I just filled the reserviour to the max level. BTW what is the best way of popping up the screws I used hand but it was not coming out so I used screw driver to pull from one side I broke the screw.

 

The center part (the lock) of the fastener is pushed in about 1/16", and then with finger nails or a thin/flat tool just pull/lift the whole fastener out. To install these fasteners, first push the whole fastener against a flat surface to push the center part (the lock) back until it snaps out more than about a 1/4" (it kinda floats) with the main body of the fastener, and then install the fastener and then push the center part in so it's flush with the main body to "lock" the fastener.

 

Two years ago I had the coolant and thermostat replaced at Mr Lube here in Montreal West, Canada. Yesterday -15c, cold air was coming out of the heater. Went back to Mr Lube and I luckily got a very competent mechanic (technician). After reading the comments here, I was very concerned that it might be a sensor or a valve or a water pump $$$$$. The mechanic knew right away what it was (LARGE MOVING AIR BUBBLE IN THE SYSTEM). He had me rev the engine at 2000 rpm for about 5 minutes while he gradually sucked out the air pocket simultaneously replacing it with coolant. Took about 15 minutes. As I was a previous customer, NO CHARGE.

No parts, no labor costs. GREAT DAY !

 

 

This is an OLD post and funny thing is the OP posted once and never posted again LOL. However I also wanted to contribute to this thread because I recently did a simple coolant drain and fill. I jacked the car up on jack stands and let it drain only from the radiator. I believe there are one or two more drain ports for the engine block but since I only had 62k miles I just did the radiator. I left the car on the stands and let it run for about 5 to 10 min to "burp" / bleed the system. The next day I checked and saw that the overflow tank was very low. I had filled it to the F the day before. I filled it to F again and it has been good. My point is whenever you do coolant service, for the next few driving sessions, be vigilant about checking the coolant level. Im actually very surprised that big air pocket of yours didn't cause an issue for 2 years?!?!

 

i knoticed this was a 5 year old post i was going to reply to the first thread when i found out that it was from 2013 first post in here.
i just had a issue late last year with heat the dealership flushed out the cooling system and i havnt had a issue since

 

No leaks.
Coolant overflow container has remained at the proper level ever since I had the coolant replaced wwhen I bought the car 1 1/2 years ago.

 

What in gawd's name are u talking about...?