No heating when standing still

[Jureb]

Hello,

I've noticed that when I'm moving and have the heating (A/C turned off) setting on maximum, there is nice hot air coming from the vents. When I stop, warm air stops blowing and a rather cold air starts to blow from the vents. (outside temperature is now cold around 0°C). I have to mention that radiator, water pump, coolant have been changed in 2021 (approximately 6000 km ago). I think water pump and radiator shouldn't be a cause. It comes to my mind that maybe I don't have enough coolant in my engine cooling system but the dash emergency light for "low coolant level" has not turned on. I opened the coolant expansion tank when the engine was stone cold and the expansion tank was basically empty (bottom filled with maybe 2cm of coolant) but I'm guessing in 1KD-FTV in j95 this might be normal as there is no "max" / "min" indication written on the expansion tank (picture below). I could however be completely wrong. How should I check the correct coolant level in my car? I've checked the owners manual for J90/J95 LC which I've found on this forum but it doesn't cover 1KD-FTV engines and is not helpful in my case. Low coolant level comes to my mind because a lot of work has been done in my car's cooling system so some air could be trapped in the system which is maybe now gone and has to be replaced with coolant.

If it's not the coolant level then the heater core might be somehow faulty... or something else. I'm interested if somebody experienced similar problems.

 

[RichC4]

Have you checked the level in the radiator by popping the cap off?

 

[Jureb]

I've removed the cap and there is some kind of metallic plate/membrane underneath the cap when I removed it. I didn't poke it in or anything, I put the cap back on.

 

[Aeroelastic]

You should see coolant at the radiator neck if coolant level is correct with cap off (only during cold engine!)

Was Your thermostat changed during the water pump & radiator work?

 

[Shayne]

Start the engine when its cold , put the heating on full , then top up the radiator .

Give it 5 minutes and your heater should blow warm , then top up the rad again .

You can't put to much in thats why you have an expansion tank .

 

[Jureb]

I've checked the situation again. I opened the radiator cap and I couldn't see any coolant, only the radiator "ribs" I also found the max/min markers on the expansion tank (not easy to spot!) and since the expansion tank is basically empty, there must be at least 0,5 L of coolant missing (rough guess). Air must have escaped the system and now there's not enough coolant I suppose. There is no "milk" in oil and there are no wet spots under the vehicle. Gonna top it up tomorrow.

 

[Jureb]

You should see coolant at the radiator neck if coolant level is correct with cap off (only during cold engine!)

Was Your thermostat changed during the water pump & radiator work?

No, thermostat wasn't changed. Maybe I should have changed it then...

 

[Shayne]

You drain a lot more coolant than you can refill . The heating system takes coolant a lot higher than the radiator, so when you turn the heating on it sucks coolant into the empty pipes dropping the level in the radiator so it can take another litre or more .

 

[Jureb]

You drain a lot more coolant than you can refill . The heating system takes coolant a lot higher than the radiator, so when you turn the heating on it sucks coolant into the empty pipes dropping the level in the radiator so it can take another litre or more .

Good to know, maybe because I don't have enough coolant it never reaches the heating system since it's higher.

 

[Jureb]

Update:
Problem solved, hot air now blows when standing still.

Poured at least 1,5 L of coolant into the radiator and expansion tank. There are no signs of coolant leaks. It seems like many air bubbles must have been caught in the system when the work was done on it.

 

[Aeroelastic]

Good to know, keep an eye on the coolant level over the next few days… Toyota cooling system sometime takes a few warm engine runs to bleed properly. You might still need to top up.

 

[Jureb]

I've been doing some more research regarding the coolant loss and I read about the problems with coolant loss on 90 series with automatic gearbox. Apparently there is an ATF cooler inside the radiator (part of the radiator?) which can get punctured and the coolant starts draining into the autobox. Is that correct?
I hope my coolant loss was connected with system air bleeding and not coolant leaking into the autobox... I mean, I have a new radiator so the problem shouldn't be there.

Now I am concerned about the previous radiator which was in a bad shape (but wasn't leaking, according to the mechanic) and we didn't check for the punctures on the ATF cooler back then. Maybe the mechanic checked for ATF cooler punctures/checked the ATF but I'm not aware of it. I assume that ATF leaks from the hoses a little when you unhook them from old to new radiator? Mechanic would have probably seen the unusual ATF color/density if something was wrong with the old ATF cooler? Could somebody tell me where the ATF dipstick is on an EU spec 1kd-ftv with LHD?

 

[RichC4]

There is a water to oil cooler for the ATF in the bottom of the radiator. You lose a little ATF when changing the radiator, your mechanic should have checked the levels when commissioning the new one. I would think he would have spotted water contamination at the same time.

 

[Jureb]

Update:
I checked the ATF on dipstick and it seemed very clear, red and oily, like it's supposed to look. Not milky at all. I hope I don't have any water in my autobox.
Pictures of ATF condition (looks orange on the dipstick because of flash on the phone camera):

Thoughts?

 

[Aeroelastic]

Mixed coolant and ATF appears pink in colour if I am not wrong from reading online stuff.

 

[RichC4]

I dropped some water in the atf while changing my radiator the other day, it goes sort of milky. That looks like clean atf in the pics I think.

 

[Shayne]

I read "milky" as lacks transparency , so i guess i'd investigate with a glass ?

 

[chadr]

Since you've already replaced the radiator, why not flush and replace the ATF for peace of mind? Not a big job and not expensive if DIY.

 

[Jureb]

Since you've already replaced the radiator, why not flush and replace the ATF for peace of mind? Not a big job and not expensive if DIY.I'

You're right.