07 TCH No Cabin Heat
 

Hi All,

This last week (in Ontario, Canada -- below freezing temps) or so I've noticed my 07 TCH doesn't produce much (any?) cabin heat. It's got around 161,000 kms on it (~100,000 miles) [side note, leaking coolant pump replaced around 80-90,000 kms], and aside from that everything seems to be working fine. The engine temperature looks normal and it gets there in the usual amount of time. The climate control seems to be sensing the cabin temperature rising eventually (I presume I'm now the heater lol) and it adjusts the fan accordingly. I have plenty of airflow out of the vents, it's just not hot or even warm air. Doesn't seem to matter if the engine is on or off, speed, etc. I really dislike my area Toyota dealer, so I'm hoping someone has a suggestion I can look at myself or "help" my local mechanic friend fix, or worst case head to the Toyota dealership having an idea what the problem is.

Edit: It looks like my coolant is on the low side (maybe 1/2 inch below the tab sticking out at the Low mark, but still fluid in the tank), and a bit of pink around the pump area again. Is that lack of cabin heat something that might happen with low coolant? Any idea if they replaced those pumps under warranty with a different/improved one or just slapped another defective one on there? (starting to think the latter lol)


Thank you very much for any insight anyone can provide!

Dave

Re: 07 TCH No Cabin Heat
 

The water pumps are replaced with an OEM unit (hence why I used after market) and yours could be leaking again. As far as your heater goes, yes, a low coolant level will cause the heater to not work or not work very well.

Hot water from the engine is circulated thru the heater core to produce cabin heat. One of the things you need to do while filling the coolant up after a water pump/coolant change is to run the heater wide open while filling the system to make sure it is also filed with coolant.

Re: 07 TCH No Cabin Heat
 

GeorgiaHybrid can confirm (or not), but I think there is a separate pump which circulates coolant to the heating system. It runs when the engine is off, and does not run when the engine is on (gets flow from the engine coolant pump). If it failed then you would get no heat when the engine was off. However, you say it does not matter. That would indicated the heater circuit is air locked, or possibly plugged. Not sure how it could get plugged though. See this information (page 8-5) on the Prius. I would think the Camry is similar, but not sure.

Re: 07 TCH No Cabin Heat
 

I don't think I'll tackle replacing pumps or anything like that myself, though in a pinch with instructions I'm sure I could manage it, but definitely outside my comfort zone on my daily driver!

Ron, I saw a "heater water pump" on a diagram, located towards the firewall, I presume that's what you're talking about.

Georgia, how much coolant should be in that tank normally when it's cold? I'm still going to get the pump looked at soon but in the meantime I'm thinking adding some coolant is an easy thing to try? If so what should I be buying?


Thanks!

Re: 07 TCH No Cabin Heat
 

The only thing that may temporarily help is to use the lowest fan speed once your temp gauge reads normal. You may not see it reach full normal if the temp is below freezing.

When it's that cold it takes my engine lots longer to warm up, usually about 4 miles. I use the lowest setting to help keep the engine warmer. I only use the 2nd fastest fan speed for a minute or two so to heat the cabin quicker. I find both the '07 and the '12 TCH being similar in this manner, the heater vs the outside cold. The '03 Corolla I had with the 1.8 liter 4-cyl engine was very similar. The heater vs the engine temp when driving in freezing weather.

I saw somewhere in the '13 TCH where it now has a coolant storage reservoir maybe located behind the passenger side headlight. This would help when making shopping stops on a cold day when in town. The engine would then heat up much faster with the help of the reservoir storing the extra hot coolant.

This summer I plan to have a look and price the storage reservoir to see if it can be added to the '12 TCH along with the extra coolant.

Others may have a different heater experience when driving in below freezing weather.

Re: 07 TCH No Cabin Heat
 

Mine seems to do that automatically, it turns the fan completely off when you first start and then gradually brings it up as the system gets up to temperature.

Re: 07 TCH No Cabin Heat
 

If you shine a flashlight into the coolant reservoir there should be a line on the side that says cold level. You will fill to that mark when the engine is cold. Adding coolant is easy. Keep in mind that coolant is toxic to dogs so be careful not to spill it or leave it open if around dogs.

Normally you mix it 50% full strength coolant and 50% water, ideally demineralized or distilled. It is also possible to buy it premixed, but is more expensive that way if you are buying a lot.

As to type the long life stuff is generally pink in color. Toyota says:

"Use either of the following:

• “Toyota Super Long Life Coolant”
• A similar high-quality ethylene glycol-based non-silicate,
non-amine, non-nitrite, and non-borate coolant
with long-life hybrid organic acid technology

Do not use plain water alone."

Toyota Specifications

Re: 07 TCH No Cabin Heat
 

For whatever it's worth mine has no hot/cold levels, only an "F" at the top and an "L" at the bottom. I may try bringing that level up a bit and see if that changes anything with the heater, but I guess at this point if the pump is leaking it's pretty pointless to put more fluid into it since that's all going to get drained out during that replacement.

I read somewhere else on this forum that the NAPA replacement pump is a good way to go, is that what you guys would recommend? I'm certainly not going to put a third OEM one on there!

Dave

Re: 07 TCH No Cabin Heat
 

If your coolant is between the F and L marks, you might have a different problem. There are several other areas that could be involved and they usually require a pro to look at them. The blend door, heater core bypass valve, temp sensor or BCM could be at fault (and others as well).

As far as I know, you only have the engine coolant pump to furnish hot water to the heater core. The advantage to the electric water pump on the 2012 and newer is the engine does not require a serpentine belt and the ECU will only turn the pump as required instead of all of the time.

Re: 07 TCH No Cabin Heat
 

Yes I quite like the idea of a totally belt-less design, it seems funny to have all that in there to run that one little pump now. Though it sounds like they've recalled the electric pump Priuses for pump issues too so I guess it doesn't solve everything!

It's definitely below the L mark, maybe 1/2 inch of fluid in the bottom of the tank when cold, so I'm hoping it's just low coolant. My plan is to give my mechanic a call first thing in the morning and see what their schedule is like and go from there. I'm guessing all those valves and sensors will show up on his fancy expensive scanner and hopefully he'll be able to track this down. Regardless I'll try to do the coolant pump replacement soon, as I presume when that completely fails a long way from home it's not pretty! Oh and I checked my records and it was replaced the first time at 64,000 kms not 80-90,000 like I thought, so that one's got almost 100,000 km / 60,000 miles on it now, which I guess isn't super terrible considering how early some of them have gone.

Thanks for all the help, I really appreciate you guys taking the time to read and reply to my questions. I'll report back anything I find out.

Dave