2002 Prius No Heat

Let's do easy questions first. Are you saying that the blower comes on and blows air, only the air isn't warm?

Does the heater report any codes? Key off, turn the fan switch to OFF. Key on and right away, press the A/C button three times then turn the fan switch to AUTO. Watch the blinks of the A/C light.

A steady fast blink means no codes. Otherwise, a two-digit code like 23 would be "blink blink ...pause... blink blink blink". If you have more than one code there'll be a longer pause between pairs of digits. When all the codes have been blinked out it wraps back around to the first one.

What's the engine coolant level in your reserve tank? How does the coolant look? Does the blue temperature light come on when you start the car? How long does it take to go out after starting?

If you have a ScanGauge II, what's the coolant temperature when you're expecting heat? If you don't have a ScanGauge, then after getting your hands on one (or any ordinary OBD-II reader, since coolant temperature is a standard parameter they should all be able to read), what's the coolant temperature when you're expecting heat?

When was the coolant last changed? What did it look like then?

There might be more questions before the puzzle is solved, but these should be a place to start.

Good luck!
-Chap

 

Ok, that's not the best news but it is one possibility I had in mind and it will definitely explain the problem. No coolant to circulate heat from the engine to your heater will definitely give you no cabin heat. And by the time you notice no cabin heat, your coolant is very seriously low. Go pick up some Toyota coolant now (the newer, Super Long Life Coolant comes premixed in the right proportions, or buy the original spec Long Life Coolant and a gallon of distilled water from the grocery store). Use alternate transportation to make this trip. Even if you do not see the red temp warning light on your Prius, with coolant this low the engine will be running much hotter in some places than others, and you risk some warpage or other damage. Some of that may have already occurred, but the first order of business is to get some coolant in there.

For instructions on coolant drain and fill, check the service manual for your car on techinfo.toyota.com for $15, or by investing more time you can find good threads about it in this forum. The tricky bit is getting all trapped air out. Some mechanics use a vacuum tool (such as "Air Lift") to speed that up.

Once you have coolant to capacity, you can run the engine up to operating temperature, and look around it for any leaks, and look at the exhaust for any appearance of steam or "white smoke" (or a sickly sweet smell). Pull the oil dipstick - does it look clear like oil, or milky/foamy? If you have none of those signs, you might take a chance and just drive it for a while, keeping a close eye on the reserve tank level.

Because your fan doesn't give you much airflow, it is probably worth checking your cabin air filter. It is behind the glove box. The glove box has two posts sticking out the sides (on the inside) that stop it at the fully open position. The official way to get to the filter is to twist and remove these two posts and let the glove box open all the way, but this flips the box upside down and dumps your stuff on the floor. Instead, look at the bottom of the glove box door for the two hinge pins. You can see these with the door closed. They pop out easily, and then you can just lower the glove box straight down so it hangs by the stop posts (which you didn't remove).

Straight back through the glove box opening you'll see the white filter carrier tray, just grab it by the handles on the ends and pull it out. My guess is you'll have a good accumulation of matter on the filter.

Toyota's filter is something like $16 new, but if you have the plain white original, it can be washed quite clean in soapy water and dried (after shaking out the worst stuff outdoors somewhere).

Good luck,
-Chap

 

Loss of freon potentially indicates a radiator problem. This could also lead to a loss of coolant.

If you open the radiator cap on the cold car, do you see coolant?

If not, do not drive car until water has been added. Then take the car to a radiator shop and ask them to see if they can find a leak and/or freon leak in the radiator.

GOOD LUCK!
Bob Wilson

 

Well, there's a bit more to it, partly because of some natural air traps in the system and partly because of weird Prius stuff like the electric heater pump (for giving you heat when the engine is stopped). The details are on pp. CO-2 and CO-3 of the service manual - I'm too pooped to type it right now, but $15 gets you access to all the manuals on techinfo.toyota.com, or if you search this forum carefully you'll find some good descriptions of the process. You do add some coolant to the reserve tank also in the last step.

I see Bob suggested a possible radiator leak (as the Prius radiator is shared by the refrigerant and the engine coolant, so a leaky radiator could explain both issues). The checks I suggested about visible leakage and coolant in exhaust or oil would be ways for you to make sure there's no cylinder head or gasket warpage or damage. If there is, we won't know for sure whether it was the cause of the coolant loss originally, or a result of operating without coolant, but either way it will be worth checking. (A compression test would be useful too, and it could help identify any head/gasket damage or burned valves. It's kind of a pain to do though, because only certain scantools are able to command the engine to crank for the test.)

In any case, get coolant in there first; then there's time for details.

Most on this forum do not advocate using any coolant other than Toyota's own LLC or SLLC (for reasons discussed at length in some other threads). It does look as if that Zerex product is attempting to be comparable. I don't know how the price compares. Around here, I see the genuine Toyota stuff for sale at CarQuest as well as at the dealer.

Plain (non-distilled) water would be a last resort, really only if you intend afterward to drain, flush well, and refill with the right stuff and demineralized water soon.

Hope this helps,
-Chap

 

Perspective:

If I remember correctly, our new Prius with warranty and collision insurance cost ~$300/month. In contrast, an out of warranty, used car (one 10 years old) will have random repair costs. Paying unexpected costs comes with a used car title. But for some of us, there is an advantage.

If you want to dive into the technology and try 'experimental' things, a used car, out of warranty is the way to go. It is this engineer's 'play toy.' <grins>

BTW, Chap is right to treat loss of engine coolant as a real risk to the engine. It would be a shame to lose a working hybrid drive train because a couple of dollars of coolant leaked out and damaged the engine, a multi-thousand dollar expense.

Bob Wilson

 

hopefully he caught it before damaging the engine, but on another thread a DIY mechanic swapped his engine out with about 10 hours labor and a $300 used engine. It amazes me how inexpensive it can be to keep these cars running.

07 prius eng swap | PriusChat

 

Yeah, being the engine in a Prius drive train is a pretty easy life, so it's been reported here that engines are generally just fine when the cars are totaled for other reasons, and demand is low, so the recycler engine prices aren't bad at all.

-Chap

 

We had frost here last night but I see Chicago's forecast looks above freezing for the week, so you might get by with water that long. Distilled/demineralized would still be the first choice rather than tap water. On the other hand, just buying a jug of the right coolant would be cheap insurance.

-Chap

 

That's probably from running for 40 minutes in the parking lot. Do a reset on the consumption screen and go take a 10 mile drive.

Was the oil on the dipstick still at the proper level?

 

Hey David, when you say

do you mean you just took it out and looked at it and put it back, or took it out and ran the engine?

The cabin filter you might leave out for a bit while you wash it, with no more ill effect than getting some extra dust in the cabin (though if you leave it out for a while you may find that the fan blade can very effectively chop random dead leaves, bees, etc., into a fill material it then packs into your heater or A/C coil fins).

But for the engine, remember that guy can breathe up to a few dozen liters of air per second, and any dust sucked in with that is abrasive.

Even if the filter is dirty, you're better off with it in until you have one to replace it. (The engine controls can actually sense the airflow, so if it's restricted by a dirty filter, the fuel mix is simply adjusted accordingly, so it doesn't have much effect on how the engine runs as it used to in older cars.)

That's an impressive close-up of your cabin filter. Maybe you could post a shot of what's on your dipstick.

-Chap