A/C drain pipe location

GregB · June 25, 2018

Hi there Lexus owners!!

I have a little bit of problem and i need your help. I want to disinfect my IS300h-s air conditioning system, and i read before that the most effective way to reach the evaporator is to lift the car up and spray the disinfectant through the condense water drain pipe. Can someone please help me to locate the pipe? Thanks a lot!!

sorcerer · June 25, 2018

Easy enough to do in this weather, just take it for a run and then look underneath when you get back, you'll see where the water is dripping from.

GregB · June 25, 2018

Hi!! Clever idea enough, i allready spotted that it is somewhere under the cover of the transmission. It is hard to see under the car, it is sitting quite low and lots of covers everywhere. The car has to be lifted and the cover to be taken off. I hoped that someone knows exactly so i don't have to mess about too much at my mechanic's place.

wharfhouse · June 25, 2018

On all the cars I have owned I have run the air con at all times summer and winter (in Auto mode) and had very few, if any, unpleasant smells. Occasionally I have bought some air con disinfectant aerosol spray that is sprayed down the cabin vents, left for a bit and then the air con run with windows open for a bit to air it just to make sure all stays fresh. If you aren't experiencing any unpleasant odours then no real need to disinfect from under the car. On one car (BMW) the drain pipe blocked and so caused condensation on the inside of the windows so had to be cleared using compressed air but that's a different problem....

GregB · June 25, 2018

Might be an option to run the aircon all the time, but i will try to foam the condenser first. As i have read many Lexus owners have the same problem.

wharfhouse · June 25, 2018

12 minutes ago, GregB said:

Might be an option to run the aircon all the time, but i will try to foam the condenser first. As i have read many Lexus owners have the same problem.

Generally unpleasant smells are caused by the air con being switched off (for example after summer) and there is some condensate left that then stagnates and breeds bacteria and hence the smell when it's run again. I don't think it's a particular Lexus problem but afflicts any car with air con and why I alway keep mine on (and accept the very small mpg hit - with modern systems it's not much and even in winter is useful in keeping windows clear from fogging up in damp conditions). However if you've had the system switched off or have recently bought the car then may be worth the disinfection but leave it on from there and you shouldn't have to worry again.

GregB · June 26, 2018

Thanks for the advice, what i will do is that i will disinfect the whole system and leave it on auto mode after. I hope i will find the drain pipe today. I'll update this topic with pics of the location if found.

cruisermark · June 26, 2018

I agree with phil above - my 430 is 14 years old and I leave the aircon all year round - never had any smell problems.

sorcerer · June 26, 2018

4 hours ago, cruisermark said:

I agree with phil above - my 430 is 14 years old and I leave the aircon all year round - never had any smell problems.

Me too.

OviR · August 8, 2023

On 6/26/2018 at 8:58 AM, GregB said:

Thanks for the advice, what i will do is that i will disinfect the whole system and leave it on auto mode after. I hope i will find the drain pipe today. I'll update this topic with pics of the location if found.

Any update, did you find location of the drain pipe?

IS300FSPORT · August 8, 2023

I tried looking for it a year back, It is above the transmission oil pan. & its an absolute bugger to get to I'd say its nearly impossible without a ramp. Maybe easier to trace the pipe from inside the car will be interior strip down.

Recently experienced a smelly air con first 2-3 seconds at start up. I left mine on always to fresh air rather than recirculate smell seems to have disappeared.

Remove cabin filter air con on spray Dettol disinfectant spray into the vents under the wiper blast 2-3 shots in 10 second intervals let it run 5-10 mins windows down & fit new cabin filter.

No smell now think it needs doing annually.

https://www.amazon.co.uk/Dettol-Crisp-Linen-Disinfectant-Spray/dp/B084R1XD3T/ref=asc_df_B084R1XD3T/?tag=googshopuk-21&linkCode=df0&hvadid=501251247783&hvpos=&hvnetw=g&hvrand=3185796776093048172&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9046656&hvtargid=pla-947060589056&psc=1&th=1&psc=1

Similar setup to the IS350

OviR · August 8, 2023

1 hour ago, IS300FSPORT said:

I tried looking for it a year back, It is above the transmission oil pan. & its an absolute bugger to get to I'd say its nearly impossible without a ramp. Maybe easier to trace the pipe from inside the car will be interior strip down.

Recently experienced a smelly air con first 2-3 seconds at start up. I left mine on always to fresh air rather than recirculate smell seems to have disappeared.

Remove cabin filter air con on spray Dettol disinfectant spray into the vents under the wiper blast 2-3 shots in 10 second intervals let it run 5-10 mins windows down & fit new cabin filter.

No smell now think it needs doing annually.

https://www.amazon.co.uk/Dettol-Crisp-Linen-Disinfectant-Spray/dp/B084R1XD3T/ref=asc_df_B084R1XD3T/?tag=googshopuk-21&linkCode=df0&hvadid=501251247783&hvpos=&hvnetw=g&hvrand=3185796776093048172&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9046656&hvtargid=pla-947060589056&psc=1&th=1&psc=1

Similar setup to the IS350

Thank you for information, very helpfully 👍

Mr_Groundhog · August 8, 2023

I bought the Lexus/Toyota AC spray and after reading the instructions to apply it (you have to apply it into the evaporator) and being told I can also do it down the vents, I decided to leave it to the Dealership: I will ask them to do it next time I take the car in for service (they may charge me an extra 15min to do it but surely they'll do it the right way?)

DavidCM · August 8, 2023

If you intend turning off the a/c,you could turn off the a/c switch BEFORE coming to a halt and then run the fan on high for a minute or so.This will blast out any moist air from the system and prevent condensation which causes the musty smell.