Heating goes cold when stationary but warm when moving

[IanW Lurker Find all posts View Profile Close IanW]

Never noticed this last year, but recently I have noticed that the heating in my 2007 LC5 is working perfectly when the vehicle is moving, but once the car has been stationary, but idling, the hot air stops working. The heating system seems to still be working in the the fan is blowing away quickly as I guess it detects that the cabin temp is dropping below the selected value, however all it is doing is blowing out more cold air. Once the car has been moving for a minute or so the heat starts coming back through the vents?

Anyone come across this before, cannot decide whether this sounds like a fault or not?

Ian.

[sweetpea Senior Member Find all posts View Profile Close sweetpea]

Re: Heating goes cold when stationary but warm when moving

Never noticed this last year, but recently I have noticed that the heating in my 2007 LC5 is working perfectly when the vehicle is moving, but once the car has been stationary, but idling, the hot air stops working. The heating system seems to still be working in the the fan is blowing away quickly as I guess it detects that the cabin temp is dropping below the selected value, however all it is doing is blowing out more cold air. Once the car has been moving for a minute or so the heat starts coming back through the vents?

Anyone come across this before, cannot decide whether this sounds like a fault or not?

Ian.

Does the engine temperature also fall when iding?

Possibly the thermostat is stuck or not closing correctly.

S.

[IanW555 Lurker Find all posts View Profile Close IanW555]

Re: Heating goes cold when stationary but warm when moving

I did not notice the engine temp falling

[Derb Senior Member Find all posts View Profile Close Derb]

Re: Heating goes cold when stationary but warm when moving

Hi sweetpea. The opposite normally happens with a duff thermostat (read locked in the open position) - when you are motoring the temperature drops off and when you are parked up the temperature slowly rises. My prado did this when I 1st drove it up across the snow on the desert road on the way home from wellington. I thought the prado had dumped all the water at 1st when the temp guage went quickly to zero and the heater did the same but when I stopped it climbed back up to normal and the heater started working again. Also took off the cap and radiator was full. Cheers, Derb.

[Skajj Lurker Find all posts View Profile Close Skajj]

Re: Heating goes cold when stationary but warm when moving

Did just get the exact same problem as u describe.
U ever find a solution for this?

[lakes Lurker Find all posts View Profile Close lakes]

Re: Heating goes cold when stationary but warm when moving

I've had the same issues...

Went to the local garage (neighbour) and he told me to let the engine warm up with the coolant cap off and the climate control on max.

I did noticed in the morning when I started up the car, I could hear a "water streaming" sound.
Another thing, the pipe against the bulkhead behind the engine was also empty when I took of the water hose. It should be full with coolant.

So I filled up the coolant reservoir above max and let the car idle for about an hour with the coolant cap off. And now the problem seems to be gone.

Give it a go.....

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: Heating goes cold when stationary but warm when moving

Oh, an airlock - that would explain the symptoms exactly!

[Skajj Lurker Find all posts View Profile Close Skajj]

Re: Heating goes cold when stationary but warm when moving

I found my problem, airlock AND a stuck thermostat (in open position).

[brad_871 Lurker Find all posts View Profile Close brad_871]

Anyone have any info on how to remove the thermostat? Im assuming mine is gone as I have the same symptoms described in this thread. I was under the impression the thermostat may be on the drivers side of the engine down the bottom? Can anyone clarify this and/or provide steps for it's removal? Cheers.

[scales82 Junior Member Find all posts View Profile Close scales82]

I had the same problem and it was an airlock, did the topup trick, no longer heard water rushing in the cab (was the original symptom, never used heater much). and the heater now works fine.

I know a necro thread but wanted to add my success, found in a google search.

[Benny2627 Lurker Find all posts View Profile Close Benny2627]

Thanks

Just noticed mine doing the same, going to give this a go tomorrow. Thanks for the good info.

[Benny2627 Lurker Find all posts View Profile Close Benny2627]

All sorted

Problem all fixed thanks to PP members and their good info, thanks.