StevenJett

Guys, I am looking for directions to replace my thermostat properly without trial and error. Mine is not closing because my heater blows cold when not accelerating.
I am not able to locate a real Shop Service Repair Manual that is generic from an auto parts store. Does anyone know the best way to access the three bolts for the thermostat housing or have step by step instructions? I would also like to buy a true manual if at all possible. Any ideas or pointers would be greatly appreciated.

Thanks in advance
Steven

carid

Hi Steven, I've got those instructions for you.
1. Drain the coolant.
2. Next, remove the right engine support and the thrust. (see pic 1)
3. remove the drive belt by unscrewing this bolt (see pic 2) and removing the cap.
4. Move the clamp and disconnect the radiator pipes. Then remove the inlet pipe by unbolting 2 nuts (pic 3).
5. Remove and replace the thermostat and gasket, and assemble everything back.
If you want a recommendation on the thermostat, I'd pick one by ACDelco, it's of good value and is the same as the OEM one, I'm giving you the link if you want.

salimshah

Couple of things before you try to change the thermostat ... does the temp gauge rise up to near half way point after about 15 minutes of driving? It may take bit longer when it cold outside and you have the heater on at full blast.

If it does not then you need to investigate the thermostat or even the temp-sensor.

Talking about service manuals .. they are multivolume publications [or at least they used to be when published]. So one has to either buy the whole set or judiciously buy the volume of interest. [for first gen it was vol2 which covered most of the engine maintenance/repair. These days it is much easier and cheaper to subscribe to TIS (on line and pay for use service). If I am not mistaken they go hourly, daily, weekly, monthly, yearly. You can down load while your subscription is valid.

For copyright reasons, CL does not publish them on line.

Salim

Clutchless

This is from the Highlander forum as it has the same engine, although the covering is different. It has nice photos.

http://www.toyotanation.com/forum/12...placement.html

StevenJett

Guys, I need some additional help. I replaced the thermostat over the weekend and the car still blows cold when not accelerating. When driving it blows hot but as soon as I come to a stop or idle, its blowing cold again. Does anyone have any additional ideas what I can check? Is there some temp sensor that could be causing this?

Thanks for your help.

salimshah

Before we look at other things, tell us how does the temperature gauge move from the time you start till about 30 minutes.
The other thing you need to tell us is about the coolant level (cold condition) peering through the radiator cap and the level in the overflow reservoir [couple of days after the thermostat change]

Salim

StevenJett

The temp gage moves to the middle of the gage after about 5 min. The coolant is full and the overflow is also full.

salimshah

This indicates the problem is with the heat/ac of the cabin.
Check air flow:
Motor blower (change fan speed to confirm)
Air ducting (check cabin filter)

Temperature setting:
Change the temp (cabin comfort) to see AC kick in on cold and heater for HOT)
Mix servo (this changes position of the duct inside the heat exchanger unit)

Salim
ps: Not sure why the thermostat was a suspect to begin with.

StevenJett

I have switched all the setting from within the cabin. Changing the temp back and forth as well as moving the flow from feet to face. Also tried the fan speeds.
If the thermostat gets stuck open, it will perform exactly the way I described my problem.

salimshah

There are three independent things that are involved and I sense a bit of confusion.

Mode: This changes the air flow from vents
MIX: adjusts the cabin temperature by mixing cold with hot.
Thermostat: a) When this term is used in vehicles, it is the control of coolant flow from the radiator the engine block. Its sole purpose is to bring the operating temperature of the engine to the desired value quickly and then regulate it. My chain of questions has eliminated this as a possibility and made we wonder why was it even a suspect.
b) when used in home it is dial that sets hot and cold temperature.

So in our case here, we have a problem with either the air flow [not direction but the flow. The air must be run over the heat exchanger to gather heat... Another member mentioned they had critters nesting in the cabin filter preventing air flow] or the MIX control.
I think the mode is working fine as you can direct the air as you desire.

Hope this helps.

Salim
PS: If your thermostat is stuck open, your engine would take a long time to reach operating temperature. The temp gauge would stay near the cold. In this case the coolant will not not get hot and would not provide heat for the cabin. Although you are not getting the heat, but the temp gauge is telling you that the thermostat is working just fine.

StevenJett

I have been working on cars for over 25 years and understand what the thermostat does in a car. If your car is running unusually cool and not building up any heat in the engine, it's likely that your thermostat is stuck open and is letting too much coolant through.

So if it is MIX control, what can I do to troubleshoot?

N4TECguy

I haven't been working on cars for 25 years but if your engine temp gauge is not on Cold and you get heat when driving, you do not have a thermostat problem in all likelihood. How many miles on the vehicle and have you ever changed the coolant? If so, what color is it? You may have a blend door issue but I would suggest you try something before you throw more parts at it.

Rev it up in neutral (ie. Not moving, just get the engine to constant 2000-2500rpm) and see if you're getting heat then. If you do get heat in this circumstance, you likely have a flow problem to the heat exchanger, maybe either a water pump or a clogged heat exchanger or clogged lines. On my 2013 VW TDI, it had a faulty radiator that threw a bunch of particulates out and clogged up the heat exchanger, eventually resulting in no heat at all.

salimshah

Hint:

May like to search for your model, but it will not be drastically different.

Salim

StevenJett

thanks, I will locate it tomorrow and see if moving it manually will change my results. I may have to leave it to the dealership to tell me what is wrong.

StevenJett

Ok, the air blows cold on both sides when not accelerating. Are there any other ideas or things I can check?