Hey guys,
Now that it has turned cold, I have noticed a heater issue with my 07 ES350. I typically have the controls set to auto @ 72 degrees. When the car is cold, the motor stays off until the car gets up to temp. After a minute or two, the fan starts to ramp up and warm air comes out. After another couple of minutes though, the air starts to turn cold. Not freezing cold, but definitely not warm. This of course makes the fan go faster, b/c it feels the interior cooling off and is trying to help.. If I wait it out, usually about another 3-4 minutes or so, I can feel the heat start to return.
I have read some posts about heater control servos under the dash. Does this apply to this car as well? Has anyone serviced this part before on an ES? I had read that it can be removed and cleaned which might buy it some more time.
Thanks!

 

Sounds like automatic temperature control sensor might be dirty or need replacement. Maybe have Toyota dealer diagnose.

 

I assume you're asking because you're out of warranty. My best tip is - just don't use auto.
If they have to take off the dash the cost of labor isn't worth it. As someone who has done it... It is not recommended at all for someone to attempt to take the dash off. - guy who spent 5 days and at least 50 hours taking apart and reassembling his whole interior.

 

Thanks for the reply guys.

xanderES - I dont think it's just in auto, but I'll find out for certain. Its just more noticeable in auto because the car senses the interior getting colder and is trying to compensate by ramping up the fan speed, which just blows the cold air harder! But I agree, I have no interest in taking the dash off. And yes, the car is out of warranty.

garsarno - Thanks for the info. At first, I thought you meant the coolant sensor, but then I did a bit of looking, and I think you mean the sensor in the lower dash panel right near your right knee? Any good tips for cleaning/testing it?

Thanks again!

 

Well, I'm not convinced its just the Auto mode having the issue. When the air started to turn cold this morning coming out of the vents, I switched to manual and cranked up the temp from 72 to 85. It still took it a few minutes before the warm air started to flow. Once it did, I switched back to Auto, set it at 72, and it was fine. So, two questions:
1. Does the temp sensor control have any input when using manual mode heat?
2. Does anyone know where the heater control servos are in this car?

Thanks!

 

Have you noticed any change in the operation of the coolant temp gauge? Is the coolant level between the L and F marks (with the coolant cold)?

 

No, the temp gauge acts as I would expect. Cold on start up, then gradually climbs to the midpoint. Once it gets off of the cold mark, that's when the fan Auto mode starts up the fan, and the air is warm at that point, for a few minutes anyway.

 

oldgrump - It occurred to me on the way to work this morning that I might have mis-read your post. I didn't check the coolant level, but I'll be sure to do that today. Thanks for the advice.

 

I finally checked the coolant level and it was low, as it was not registering on the reservoir. I added probably a quart before it filled up, but I wonder if I need to check again after the car has run and the thermostat opens up, because the heater was still having the same issue.

I guess I have been somewhat negligent in checking this car because it is 'newer'. My other car is a 98 Expedition with 190k miles, and I check it all the time. My attitude has been adjusted.

oldgrump - Thanks for the tip about the coolant. I doubt I would have checked it until a more serious problem arose.

I'll check the level again tomorrow morning to see if it needs even more.

 

If it was only about a quart that it took to bring the level up to between the L and F marks then I'd be surprised if that makes any difference with the heater/AC system issue that you described. The total system capacity is 9.5 qts.
But......I would sure have the area around the coolant pump leakage witness weep hole checked for indication of coolant leakage just as described in the SB, as well as the other usual areas for coolant leakage. You have had, or are having some leakage of coolant.

 

I just realized that there is a radiator fill cap on these cars and that the "reserve" coolant tank is not that big so it may only have a capacity of a quart or so. If you find that the reserve/expansion tank level is basically zero (below the "L" mark) then to actually determine how much coolant has actually leaked from the system you have to remove the radiator cap (coolant COLD) and check if the radiator is actually full or not.
The radiator cap is under the plastic fairing and just in front of the oil dipstick. If the coolant is not right up to the top of the rad (visible when you remove the cap) then the coolant level is way low and coolant should be added (keep track of how much you are adding) to bring the level right up to the rad cap seal seat. Install the rad cap and the plastic fairing and then run the car until the engine and coolant are fully warmed up. Let the engine/coolant cool down and then add coolant to bring the level in the reserve/expansion tank to between the "L" and "H" marks.
Once again.......these cars (and every car for that matter) do require the coolant level to be visually checked every so often. If the coolant level has dropped to below the "L" mark or lower as I explained above then the source of the leak has to be found, particularly with the known issue of leaking from the coolant pumps on these cars.
I urge everyone that has a car where the powertrain warranty coverage is coming to an end to check the coolant level BEFORE the powertrain warranty expires.

 

I would wait until the car is cool and check the coolant level in the radiator. The ES has had issues at times with water pump leaking, and low coolant in cooling system will cause issue with temperature in vehicle.

I would check this before condemning the servo actuator on the system. It is all one assembly at this point, not like the RX, and is not cheap....

 

Thanks for all of the information! Over the past couple of mornings, the heater has worked as expected. I will remove the plastic cover and double check the radiator level to be sure its full. As I think back, I'm pretty sure it was leaking fluid over the summer, but from where the puddle was, I thought it was just condensation from the A/C. But I could never explain why it had a very light pink tint... well now I know. I have not seen the puddle for some months now, so hopefully it was one of the temporary leaks as described in the TSB. The car is out of warranty (and has been for some time), so the water pump is on me if it goes bad. I'll report back when I check the radiator and the water pump weep hole for coolant residue.

 

Have you checked fluid level yet?

 

ELI,
Yes, I finally checked the fluid yesterday. It was 'maybe' a cup low, and that was with me almost overflowing the radiator. I have been keeping an eye on the garage floor, and so far, so good. On the next oil change, I'll take a peek at the water pump and look for coolant residue.
I am half temped to cut a couple of inches from the factory plastic under the hood so that I can check the radiator w/o having to remove that piece. Seems odd that they would cover that part up. It right at the edge, so it would not take much cutting to do.