Interior Heating Blowing Cold

[Rabbijon]

Hi, I have an 07 t180 rav 4. The problem I have notice recently is the interior heater takes a lifetime to blow hot air. It literally takes 45 mins to start blowing hot. Till that point though it blows cold air. After that it seems normal. Even when on hi it still takes about 45mins to start blowing hot. Anyone have any ideas where to start looking/investigating to fix it.

[anchorman]

Where is the temp gauge during all this time?

[Rabbijon]

My temp guage is at the half way mark, which I assume is normal and healthy?

[anchorman]

Got to go out but will come back later.

[Rabbijon]

Okey doke. Any help would be great. Thanks.

[Aycee]

I would have said a failed thermostat stuck open but as temp gauge is showing normal probably not the case. Have you recently filled it with coolant, could there be an airlock in the heater matrix?

[anchorman]

OK. First of all, it is well known that these engines take a really long time to heat up. This is because diesel engines are highly efficient and most of the heat generated from combustion goes straight out through the exhaust. The temperature gauge is not calibrated so you tend to get up to full heat from the heater only when the engine is really hot and that means after it has settled (no longer rises) at normal temperature, half way up the gauge. To help with warming from low temperature, the heater is fitted with a PTC (positive temperature coefficient) radiator. It is an electric radiator that sits in the heater inlet and can be powered up in 3 stages depending on how cold it is outside. The whole thing is controlled by a heater amplifier which uses information from various sensors inside the car and out. The trouble is that the internals of the heater are by no means easy to access and the system is not easy to check without the proper toyota gear. So before you start, you can save yourself a lot of frustration by assuring yourself there is something wrong. I say again that they are normally very slow to heat up and that the heater cannot deliver full heat until it is fully hot and that may take quite some time. There is normally no benefit in turning the temperature up. If you set it at auto and your desired temp (say 20) it will heat up the interior and then stabilise (start mixing hot and cold air to maintain the set temp). If you turn the temp up to say 25, it will just add more hot air to the mix. You can spped it up somewhat by using the recirc function but it may cause the windows to steam. Make absolutely shure the cabin filetr is clean (see the pinned instructions).

If you look down the back of the engine you will see the heater pipes. If you lean down and feel them when you are confident the heater is working OK, one should be quite hot to touch and the other marginally less so. If you make the same check when it is warming up you can make some comparisons on what is reasonable. If you are any good with electrics and stripping cars, you can runs some electrical checks of your own. Let me know and I will send you a copy of the manual. However, if not you really need to take it in and get it checked as the Toyota DLC3 tester they use can check all of the components as long as the operator knows how to use it.

[Davrav]

Would the heater/aircon self test function help to point to a potential cause in this case Anchs?

[anchorman]

It does cycle all the servos and if you could look behind the dash it might show if the hot/cold mix servo was working OK. The trouble is, you can't and it is probably the hardest to tell if it is working (you can hear the direction and the recirc ones working).

[Rabbijon]

Hi thanks for the replies. Ive only noticed this problem in the recent cold snap. Bought the car back in summer and never noticed anything till now. I will time exactly how long it takes tomorrow to get heat through the blower tomorrow morning on my way to work whilst watching the temp gauge. As for stripping cars and electrics, im no car expert but I do like to give things a shot being quite handy (with instructions). Electrics are fine with diagrams. I will also check the heater pipes tomorrow and post result tomorrow.

[Rabbijon]

As for the length of time for the engine taking time to heat up, I had an auris t180 prior to the rav and it never took as long to get hot air through the vents.

[Big Kev]

.....aye....but the engine was nearer in that wee tiny car...lol....ma SR180 took ages too, but as he from the hills says, you almost certfully have a problem. Always at the cauldest times.....anybody else notice that.....?

Big Kev

[Davrav]

Hi thanks for the replies. Ive only noticed this problem in the recent cold snap. Bought the car back in summer and never noticed anything till now. I will time exactly how long it takes tomorrow to get heat through the blower tomorrow morning on my way to work whilst watching the temp gauge. As for stripping cars and electrics, im no car expert but I do like to give things a shot being quite handy (with instructions). Electrics are fine with diagrams. I will also check the heater pipes tomorrow and post result tomorrow.

Don't want to worry you but...........................It took Toyota four days to strip, diagnose and re-assemble mine - the WHOLE dash has to come out.

[Rabbijon]

What was the damage to your wallet for that davrav. 3, 4 figures?

I was hoping it was just a case of the rav takes ages to heat up. Ah well.

[Davrav]

Just a thought, are you aware of how to get the supplementary interior heater going to clear the windscreen?

Basically just switch on the front windscreen button on the heater controls. I am having to use this in the mornings down here just now. It helps to heat the cabin prior to the engine temp coming up.

I have the aircon set at 18.5 all year round - Scots antecedant genes I guess............................

[Rabbijon]

I usually turn that front windscreen button off once Ive left the house. I switch the car on for 5 or so minutes before I head off for work with that windscreen button on to clear the windows while I scrape the frost off. I will leave it on tomorrow and see if it makes a difference.

[Davrav]

What was the damage to your wallet for that davrav. 3, 4 figures?

I was hoping it was just a case of the rav takes ages to heat up. Ah well.

It does indeed take ages to get warm but not 45 minutes in my experience.

Fortunately the repair was covered by the warranty at that point.

Have you checked the cabin filter as Anchs suggested - it's dead easy to do. As the system will automatically recirculate cabin air to speed heating I'm guessing a blocked or dirty filter would inhibit this considerably.

[Guest]

as a rough estimate it takes about 4 miles to get warm/hot air coming out the vents on mine, that is one mile nose to tail and three miles on A and Motorway roads, I am sure I could leave it on the drive a week and it would only get tepid air out and I believe that is the supplemental electric heater doing its work.

Gus

[anchorman]

This 2012 of mine is the fastest I've come across. Maybe assisted by the auto box.

Gus. Without the cooling fans, a 4.3 left ticking over would eventually boil as hard as it seems to believe.

[Rabbijon]

I will check the filter tomorrow as well. Will let you all know how I get on. Many thanks for the help with this.

[Rabbijon]

Hello again. I timed it exactly today, temp gauge took just under 10 mins (around 3 miles) to get to half mark and the heater started blowing out hot air ten mins later, although it wasnt roasting. Outside air temp was 3 degrees. On the way home it was much quicker even though the Car had been parked at work from 9 till 4. I used the windscreen heater on the return trip which I assume is why it was quicker on the way home. Outside air temp this time was 5 degrees.

Are these times correct and Im now only noticing it due to the cooler weather or is there something up. On saturday it was a good 45 mins before I got a decent heat through. That was without the windscreen heater on and an outside air temp of 0 degrees perhaps just below freezing.

What kinda times does it take others rav's to start blowing out a decent heat?

[Davrav]

Blimey, if you're only doing three miles in ten minutes it can hardly be getting off tickover [or do you live in Brighouse?]

Does sound about right to me though - I was shocked too when I encountered my first winter in the RAV

Did you check the cabin filter?

[Rabbijon]

Still to check cabin filter, hopefully get the chance tomorrow. The 3 miles is getting out of town through hordes of traffic lights. I will continue to check the times it takes to heat up. I am shocked at the length of time if it is normal. Apart from that, its a great car. Oh and the run flats but im slowly getting rid of them.

[firemac]

Still to check cabin filter, hopefully get the chance tomorrow. The 3 miles is getting out of town through hordes of traffic lights. I will continue to check the times it takes to heat up. I am shocked at the length of time if it is normal. Apart from that, its a great car. Oh and the run flats but im slowly getting rid of them.

I have to say that I always found that my D4D RAV & LC took ages to warm up in winter. I put it down to the fact that diesels are much more thermally efficient than petrols so there is less residual heat going to the block & thence to the water jacket. My Saab & BMW were also horribly slow to warm up compared to the petrol engines that I was used to for years beforehand.

[Big Kev]

Hello again. I timed it exactly today, temp gauge took just under 10 mins (around 3 miles) to get to half mark and the heater started blowing out hot air ten mins later, although it wasnt roasting. Outside air temp was 3 degrees. On the way home it was much quicker even though the Car had been parked at work from 9 till 4. I used the windscreen heater on the return trip which I assume is why it was quicker on the way home. Outside air temp this time was 5 degrees.

Are these times correct and Im now only noticing it due to the cooler weather or is there something up. On saturday it was a good 45 mins before I got a decent heat through. That was without the windscreen heater on and an outside air temp of 0 degrees perhaps just below freezing.

What kinda times does it take others rav's to start blowing out a decent heat?

Nah.......something far wrong if it takes twenty minutes to blow wam air. I am 7/8 minutes drive from City centre, usually by not too busy M80 / M8. Heater in my Sr180 was slow, but was well warm by then. Methinks youwill be removing a cabin filter which is totally gubbed, possibly damp with heavy contents.

Big

Kev