Water running/dripping down windshield

[YarisHybrid2016]

Hi,

My Gen. 3 had a massive problem with this last year; seems the Gen. 4 also has a problem.

My windshield is literally dripping with water, and there are multiple trails from water running down from the roofline down the windshield on the inside.

Is this normal or a sign something isn't sealed?

My Gen. 3 had a teaspoon or so of water run out of the driver side vanity mirror pivot point when the mirror was moved. That was bad enough.

So far, there are 7 or 8 trails where water ran down the window. It seems to be dry at the base of the window though.

I'm worried about it running into the sensor box mounted at the top of the window. Several of the water lines ran either side of this; I'm unsure if anything has run inside it.

[TonyHSD]

Water should not run from inside the windscreen, unless heavily steamed windows for some reason. 

[Bernard Foy]

I’ve owned quite a few different Toyota models, including the mark3 and mark4 never had any trouble with condensation on the inside of the car. I keep the air intake from out side, have the a/c on all the time, keep the temperature @22 Cel fan at 1 or 2 as necessary never have any condensation. Maybe I’m lucky🤔

[YarisHybrid2016]

Hmm. I run AC all the time, and set the heater to 25 in these conditions.

The car mists up quite a bit, but it does clear.

No signs of water ingress anywhere else.

Not sure how to check for leaks besides flooding the car with water for half an hour. Not keen on that idea.

[Cyker]

I had that when I had my windscreen replaced; Initially thought it was a leak, but now I think it was just damp in the car, as when the windscreen was being put in it was cold and there was hail at one point, and even tho' the car was under a canopy I suspect some may have been blown in.

I cleaned it all up and thankfully it hasn't returned, although I do use the AC all the time and the car has silica gel bags scattered everywhere to help keep down the internal humidity!

You could check if it's the windscreen seal by running a hose over the top edge and seeing if the water gets in, but if your previous car did this too, it may just be where you live has a lot of moisture in the air, esp. if it's only manifesting now - Do you leave it open for extended periods, e.g. for loading stuff, or is it just open-get in-shut?

Might be worth giving the windscreen a good wipe down inside with some glass cleaner just in case there's a chemical film on it; That was a real issue with mine when I first got it, with all the new plastics off-gassing.

[Gren]

It could be water off your feet making the carpet damp, then condensing on the windscreen.  One of my cars has rubber floor mats and sometimes there's enough water off shoes to be able to lift the mat out and let the water drip off.

[Big_D]

I also find that cleaning the inside of the windscreen helps. My logic says that if the inside of the windscreen is clean, there is less dust for any condensation to cling to, and then less chance of water / condensation forming on the inside of the windscreen.

I used to use Autoglym Autoglass, but found it took ages to get the windscreen a really clean. I have since started using Gtechnic G6 and this seems to be brilliant. 

I also run the a/c throughout the year.

I had a fair amount of condensation in the Yaris unit a couple of weeks ago when I first used the Gtechnic. Since then, there has been nothing (he says with his fingers crossed)

[Jules88]

Had this the other day. Initially thought they were on the outside and just ice melting but when it wouldn't clear from the wipers... D'oh, had to quickly wipe them before it rolled onto the dash. Was about 3 or 4 trails.

The condensation is driving me crazy, always delays my journeys. I have my break at work sat inside the car and about halfway through it's all steamed up. Gonna either have to stop doing that or get a load of moisture absorbers.

[Rhymes with Paris]

Apologies if covered already, but do you all crack a window open a bit as soon as hot air blowing out out of the vents or even before ?

Obviously not if aircon on , but with recirc setting, then maybe aircon when engine hot.

Done this for a long while with older cars, and dry ,touch wood.

I appreciate this may be different with hybrids and no engine heat to help 

[MikeSh]

1 hour ago, Rhymes with Paris said:

Obviously not if aircon on , but with recirc setting,

I have aircon always on, never in recirc (unless I'm going into a bank of smoke or suchlike).

 

1 hour ago, Rhymes with Paris said:

I appreciate this may be different with hybrids and no engine heat to help

Whatever makes you think that? My hybrid is probably the quickest to get heat out of all the ICEs I've had. Our 900cc Smart takes twice or more as long to warm up.

[Cyker]

I guess it depends - Of the 3 models of Yaris I've owned, the Mk2 1.33VVTi was by far the fastest car to heat up, with my Mk1 diesel taking a significantly longer amount of time, and my Mk4 hybrid being the worst, or at least the most variable.

If I get on a fastish A-road it will warm up fairly quickly as you say, but if I'm in slow urban traffic it literally never warms up if I just leave the HVAC on - The fans remove the heat faster than the engine can make it, so the combustion efficiency is garbage (Cold ICE = Inefficient ICE) and I'm still cold!

In contrast, when I was hauling donkey up the M1 yesterday, it got hot so fast I think the HVAC got confused as it started burning my face off   

Actually, it was a bit weird, as when set to 20C it was blasting volcano hot air at me face, but if I set it to 19C it was like it wasn't blowing any heat at all!

I hit the Auto button and it stopped blowing at my face and changed to footwell (I think, it kept changing??) and also felt colder until I set it to 23C to feel any heat. Was a bit of a weird glitch

 

[MikeSh]

1 hour ago, Cyker said:

Mk1 diesel taking a significantly longer amount of time

Diesels tend to be slower - more efficient, so less excess heat, and more metal in them due to higher compression ratio.

1 hour ago, Cyker said:

Mk4 hybrid being the worst, or at least the most variable.

I guess it's the trade off of greater efficiency, as with diesels.

[Rhymes with Paris]

2 hours ago, MikeSh said:

2 hours ago, MikeSh said:

Whatever makes you think that? My hybrid is probably the quickest to get heat out of all the ICEs I've had. Our 900cc Smart takes twice or more as long to warm up.

 

Hello Mike, I did not say that I think it.

I simply don't know as I don't own,or have driven a hybrid.

Maybe you can find it in your heart to forgive me for guessing,if not no worries as the Aussies say.

I am too old and tired to get into spats with anyone .

[Cyker]

52 minutes ago, MikeSh said:

Diesels tend to be slower - more efficient, so less excess heat, and more metal in them due to higher compression ratio.

I guess it's the trade off of greater efficiency, as with diesels.

Yeah that's exactly it - the 1ND-TV and M15A both have relatively peak thermal efficiencies so there is a lot less 'waste' heat to warm us up. On balance I'd rather that energy go to moving the car than heating us up, so probably shouldn't complain, but I'm going to wear my teeth down prematurely from them chattering in the morning if we have too many cold days!

 

[MikeSh]

1 hour ago, Cyker said:

I'm going to wear my teeth down prematurely from them chattering in the morning if we have too many cold days!

Yes. EVs often go large on heat pump A/C and heated seats. (P)HEVs should really be going the same way, but then it puts the sticker price up.

[TonyHSD]

Toyota hybrids definitely fastest to warm up from all ice cars , likely to be fastest to lose heat too. 
Excess moisture from inside the windscreen often a sign of water ingress into the cabin or wrong hvac settings. 
Using ac will help a lot against moisture and steaming up windows especially if you drive on short town trips where the engine doesn’t have enough time or load to reach normal operating temperature. Set in auto mode, select AC ON and chose your preferred temperature, let the system take care of the rest. If for any reason you don’t want AC to be ON or prefer manual control over speed fan , air flow etc best winter settings are as per the picture. 

[YarisHybrid2016]

After starting this thread I tried what was suggested above, and so far, no more problems! I run the HVAC at 20 or 22 (just to get it warm), and with fresh air open.

I blasted the heater and got the interior nice and warm and blasted the air at the windshield the entire time. I then gradually reduced the temperature to get the moisture out, and the last few days of -2 deg. C it was dry inside with light misting only, and no sign of water running anywhere.

Thanks for the tips! Also getting better fuel economy from not running the heater at such a high level, too. Win!

[YarisHybrid2016]

On 12/3/2023 at 9:15 PM, Cyker said:

I guess it depends - Of the 3 models of Yaris I've owned, the Mk2 1.33VVTi was by far the fastest car to heat up, with my Mk1 diesel taking a significantly longer amount of time, and my Mk4 hybrid being the worst, or at least the most variable.

If I get on a fastish A-road it will warm up fairly quickly as you say, but if I'm in slow urban traffic it literally never warms up if I just leave the HVAC on - The fans remove the heat faster than the engine can make it, so the combustion efficiency is garbage (Cold ICE = Inefficient ICE) and I'm still cold!

In contrast, when I was hauling donkey up the M1 yesterday, it got hot so fast I think the HVAC got confused as it started burning my face off   

Actually, it was a bit weird, as when set to 20C it was blasting volcano hot air at me face, but if I set it to 19C it was like it wasn't blowing any heat at all!

I hit the Auto button and it stopped blowing at my face and changed to footwell (I think, it kept changing??) and also felt colder until I set it to 23C to feel any heat. Was a bit of a weird glitch

 

The feeling of heat definitely changes if you drive hard/fast for the same temperature setting. If you listen to the HVAC system carefully at low fan set to face/floor, and turn the temperature down gradually, 20+ it just seems to get warmer. 19 it starts to bias towards the AC side, 18 more so, then as you go down towards 15 the fan speed actually increases, even though you didn't change the fan speed. At LO, it is super cold and will start the AC continuously, and the fan will run a bit faster than at 20.

I've found setting the HVAC to 20 or 22 is about optimum for warm air. Anything more just causes the ICE to run killing fuel economy, but never getting warm in slow/town traffic. Fan speed has a huge effect on peak water temperature, and I can get it so I only ever get 1 bar. I don't like it though as I don't think it is good for the engine. I'd like to know what the water temp around the engine block is. I suspect it simply doesn't circulate the water very much at all.

[TonyHSD]

No worries for the engine temperature as long as there are 5 min past initial cold start in any cold weather the engine oil temperature will be at least 30C° or more and coolant around 40C° + , therefore no risk of any mechanical issues, plus your cars running ultra thin oils with low viscosity and fast fluidity in low temps , 0w8, 0w16 or 0w20. 

[MikeSh]

9 hours ago, YarisHybrid2016 said:

and I can get it so I only ever get 1 bar.

Most car temperature gauges don't start reading (needle lifts off the bottom) until there's a fair bit of heat in the water, by which time as @TonyHSD says it's enough for all normal operations.

[MikeSh]

Without going too far off topic, I've always assumed the heater matrix in hybrids is supplied by a small electric pump, separate from the engine pump. Otherwise how does it keep heating when the engine is off?

Is that correct? If not, what is the system?

[YarisHybrid2016]

20 hours ago, MikeSh said:

Without going too far off topic, I've always assumed the heater matrix in hybrids is supplied by a small electric pump, separate from the engine pump. Otherwise how does it keep heating when the engine is off?

Is that correct? If not, what is the system?

As I understand the system, the coolant runs out of the engine, through the cabin heater block and back around. All that happens is a valve opens to let more or less coolant through the cabin heater block.

In the case the engine gets cold, the rate of water circulation reduces, until the water temp drops to a minimum defined threshold (the higher of cabin heat demand or minimum block temperature).

I have noticed that above 18-20 cabin temp setting, the engine starts earlier to maintain a higher temp. i.e., at 20, it will fire up at 1-2 bars on the temperature gauge; at max it will fire up at 3 or even run the ICE nearly continuously.

The fan seems to make a huge difference. If you sit stationary, or in slow moving traffic, have the heater set to 20 or 22, and the fan flat-out, it can prevent it getting warm at all.

I noticed on my Gen.3, and also on the Gen.4, if you have the blower set to demist the window (floor/windshield) or press the windshield button, it will be more aggressive at running the ICE to maintain temperature than if it is set to face or face/floor. Windshield only it is most aggressive. The end-result is it hits fuel economy quite hard if you have it set to demist only, high temp, and mid/high fan setting.

Setting floor/demist, 2-3 bars for fan, and 20-22, it doesn't try to run the ICE nearly as much, but remains just as effective.

[TonyHSD]

21 hours ago, MikeSh said:

Without going too far off topic, I've always assumed the heater matrix in hybrids is supplied by a small electric pump, separate from the engine pump. Otherwise how does it keep heating when the engine is off?

Is that correct? If not, what is the system?

The small electric pump is actually the water pump of the engine which is ecu controlled and electric so no need engine to be running as long as the coolant is warmed up  the pump will circulate it through the heater matrix and you will get cabin heat. This is the reason why we can see coolant temp drops down when we drive in towns and engine does not get loaded.

One trick to share how to warm up cabin without using petrol and engine been on, works only after a long journey and you stop and go out and back within 5 min or so.
Start the car and your hvac will blow hot air as per your pre set cabin temperature. All you need is to watch the temperature gauge, once it goes down to one bar turn off the car before the engine kicks in. The car will be warmer than before and no petrol used, but your coolant will be colder so the next turn on of the car the engine will kick in immediately. 
 

[MikeSh]

1 hour ago, TonyHSD said:

The small electric pump is actually the water pump of the engine which is ecu controlled and electric so no need engine to be running

Ok, I was assuming there was an engine driven pump. That makes sense.

Aside from the thermostat (assuming there is one) is there a valve to prevent the pump pushing water round the radiator when the engine is stopped? Obviously losing heat through the radiator then would be a waste meaning the engine has to run more, but then the additional cost and complexity of preventing that might be deemed too much.

 

1 hour ago, TonyHSD said:

works only after a long journey and you stop and go out and back within 5 min or so.

On my MK3 I can go out after 30 mins or so and get heat without the engine starting. The temperature gauge barely seems to go down in that time.

[TonyHSD]

1 hour ago, MikeSh said:

Ok, I was assuming there was an engine driven pump. That makes sense.

Aside from the thermostat (assuming there is one) is there a valve to prevent the pump pushing water round the radiator when the engine is stopped? Obviously losing heat through the radiator then would be a waste meaning the engine has to run more, but then the additional cost and complexity of preventing that might be deemed too much.

 

On my MK3 I can go out after 30 mins or so and get heat without the engine starting. The temperature gauge barely seems to go down in that time.

As far as I am aware only the thermostat controls the coolant loops, in Corolla 2.0 and maybe Yaris mk4 this is electronically controlled too. 
The water pump remains off for the first few minutes after engine starts up and hvac settings are in auto to let coolant warm up quickly. 
All systems works together very well in these cars.