LS430 (2003) Heaters not working properly

[Abid221]

Hello

The LS430 only blows warm air when I accelerate. What's up with it.? 

Need my heaters working quick before winter sets in. 

 

Thanks 

[steve2006]

Assuming the engine is fully warmed up and confirmed by temperature gauge, low coolant level which should flag a warning light or poor coolant circulation (when was the water pump last replaced).

Check the heater valve mounted on the engine bay firewall is open by feeling both rubber pipes connected to it, they should both be a similar temperature indicating the valve is open and coolant is flowing.

[Abid221]

3 minutes ago, steve2006 said:

Assuming the engine is fully warmed up and confirmed by temperature gauge, low coolant level which should flag a warning light or poor coolant circulation (when was the water pump last replaced).

Check the heater valve mounted on the engine bay firewall is open by feeling both rubber pipes connected to it, they should both be a similar temperature indicating the valve is open and coolant is flowing.

I've never changed the water pump in my 3 years ownership. Previous owner changed the cam belt so might have also changed the water pump. Not 100% sure. 

 

I've noticed during my ownership that the coolant nearly always goes below 'LOW' level when cold. Is this an issue? 

[steve2006]

The level markings are based on cold coolant levels so if it is below min/low with a cold engine then yes I would top it up between the 2 level indications.

[Abid221]

I've just taken 2 pictures. 

The temperature gauge is is in the middle. 

But the coolant is low.. should I top it up. 

a few days ago I opened the coolant tank cap when the car was on and hot and the coolant when right up. 

 

[Abid221]

just got instant results. 

topped up the coolant and it's working now. 

so do you recon there's a leak? 

[Abid221]

spoke too soon. 

I topped up and for some reason the coolant dissappears and goes low again. 

Does this mean that the coolant was really really low and I just have to keep topping it up up till it gets to the right level? 

[Malc]

Adam hi, good morning

Are you using this car as a daily driver ? or has it been laid up thru' the covid time and you're just bringing her back into regular use ?

Reason I ask is that after mine was effectively left for a long long time doing almost nothing I too had some very strange coolant level problems ..........  when she got back into daily use mode

Malc

[Abid221]

10 hours ago, Malc said:

Adam hi, good morning

Are you using this car as a daily driver ? or has it been laid up thru' the covid time and you're just bringing her back into regular use ?

Reason I ask is that after mine was effectively left for a long long time doing almost nothing I too had some very strange coolant level problems ..........  when she got back into daily use mode

Malc

It's in daily use. I do 150 miles a week (on LPG). 

Not sure what's going on with the coolant levels. 

[GEN]

I'm not mechanically minded so, for what it's worth, I had a similar experience (same symptoms) with my Ls600hl: it needed a new radiator and it seems I got to the garage not a moment too soon (the coolant temperature was going through the roof by then) so check the radiator?

(I seem to recall some of the Ls430s had a problem with the radiator coolant feeding through to the transmission?)

Hope it's none of the above.

[Malc]

Oh my YES  😵 ..........  that sure is an age old issue with the Ls430, 460 and 600 .......... there's a likely potential leak at some time from the radiator to transmission connection at the radiator and the leakage simply destroys the gearbox ....  it's an inherently bad design from scratch ...... and that does involve changing the radiator BEFORE it destroys the gearbox ..........  and it's not just Lexus either I've read on here too

I was unaware a tell tale sign could be loss of coolant from the reservoir, but of course that could readily happen

There's people on here who have experienced this issue for sure, first hand and will hopefully come to your rescue with more appropriate advice

Thankfully the Ls400 doesn't suffer from this ignominy 

There's plenty of write-ups on here about it when you start searching

Good luck with it all .................... if it is this then it will need sorting very very promptly and could be a comparatively cheap fix to replace the radiator, of course with the correct one for your specific car as I've also read that there are variations at the hose connection points too

Malc

[steve2006]

Spot on Malc, if you are losing coolant and there are no obvious signs of where from there is a good probability that the combined radiator/ transmission cooler has failed internally allowing engine coolant to mix with the transmission fluid with expensive if not terminal results to the transmission.

Personally if the radiator has never been replaced I would not bother with testing the system just buy a replacement of the correct type and have it fitted ASAP.