Ls430 Gearbox/transmission Design Question

cruisermark · June 5, 2015

Hi Guys

We all know the pre-facelift 430s have the bad design of the transmission cooler pipe running through the rad which have known to leak and mix fluids resulting in gearbox failure.

Can sombody tell me wether this design was modified on the post-facelift (53 plate onwards). I have a facelift 430 and always thought this was the case without having officially read it anywhere.

I have just seen a facelift 430 on eBay with the same problem hence why i am asking here

thank you

ColinBarber · June 5, 2015

I don't think it was changed. It is a common design that Toyota use on most of their vehicles. The LS has always had this arrangement. Not sure why the early 430s seem to suffer more than older 400s. The GS430s seem fine too. Maybe the LS430 radiator is subject to more vibration, I believe it is the joints that fail rather than corrosion.

The-Acre · June 6, 2015

I always understood the design was the same. All I can say is that fitting the cooler was very easy, and inexpensive. Last Monday I gave it a really good test, driving through London with very slow, and lots of non moving traffic, and all seems fine. The other way of course is just to replace the radiator. That would prevent the problem and take away the possibility of a near future radiator failure.

cruisermark · June 6, 2015

thanks for the replies guys - how would one check if this failure - i was washing the car today and check the fluid level which at the right level and colour - i also check the oil cap and was dry - not much to see.

these oil cooler pipes do they leak on the outside aswell i.e will their be drips on the ground

a pipes diagram would be helpful showing the pipes etc.

Loathecliff · June 6, 2015

So not all Lexus rads fail the Valeo mixing way. - (Now there was a case for a class action when there was an epidemic of failures some years ago. It's possibly still happening)

http://www.ebay.co.uk/itm/2004-LEXUS-LS430-AUTO-BLUE-/231583901172?pt=LH_DefaultDomain_3&hash=item35eb79e5f4

Driving home one evening a few months ago, one of the transmission cooler hoses parted company with the radiator and dumped all of the automatic transmission fluid.

........

Being picky, the goal is really transmission oil temperature maintenance, so surrounding transmission oil pipes with rad temperature liquid is a good thing.

It could be said that keeping the oil temperature low is not that good an idea. A UK winter, driving in below zero temperatures plus wind chill; but don't ask me what the alternative is for us hapless owners.

ColinBarber · June 6, 2015

They don't seem to fail until vehicle are at least 10 years old. Preventative maintenance may be the best advise, replace the cooler inside the radiator every 10 years to avoid the issue.

Loathecliff · June 6, 2015

^ I assumed the radiator was a throw-away unit. It really can be taken apart?

ColinBarber · June 6, 2015

it can yes, here is an example diagram:

http://www.lexussouthatlantaparts.com/images/parts/toyota/fullsize/164420.jpg

The-Acre · June 6, 2015

thanks for the replies guys - how would one check if this failure - i was washing the car today and check the fluid level which at the right level and colour - i also check the oil cap and was dry - not much to see.

these oil cooler pipes do they leak on the outside aswell i.e will their be drips on the ground

a pipes diagram would be helpful showing the pipes etc.

The pipes that go to the bottom of the rad are rubber, it seems to be internally where the corrosion occurs. Also there's conflicting info, some say you can't cool the transmission enough, some say it can be cooled too much. What I do know is that my aftermarket cooler still gets very hot, so its not over cooling it.

cruisermark · June 6, 2015

yes i see it now in the diagram now and understand it a bit better.

im going to give this some serious thought and do a but more research

ColinBarber · June 6, 2015

The pipes that go to the bottom of the rad are rubber, it seems to be internally where the corrosion occurs.

Apparently it isn't corrosion that causes the problem, and there certainly shouldn't be any corrosion if Toyota coolant is being used. The pipe joints at the cooler body, inside the rad, seem to fail.

Also there's conflicting info, some say you can't cool the transmission enough, some say it can be cooled too much. What I do know is that my aftermarket cooler still gets very hot, so its not over cooling it.

I'd say both apply. The cooler inside the radiator is in a controlled temperature environment. It helps get the transmission up to temperature quickly and maintains it at the designed temperature. An external cooler could potentially under cool in hot weather and over cool in cold weather. In this country we don't really have the have extremes of temperature that this would be such an issue, provided a cooler of the approximately correct size is used.

tonyflynn1 · June 6, 2015

Didn't someone from here fit an aftermarket cooler recently?

That would surely negate the problem.

cruisermark · June 6, 2015

yes that was "acre" above who done it recently

The-Acre · June 6, 2015

it can yes, here is an example diagram:

http://www.lexussouthatlantaparts.com/images/parts/toyota/fullsize/164420.jpg

But the problem is still internal, regardless of whether it's corrosion or joint failure. I looked into taking the bottom of the radiator apart but couldn't find any info at all. With the aftermarket cooler it gets up to temperature very quickly, perhaps even quicker than if it was running through a cold radiator at start up. It's certainly not being excessively cooled when driving, it still feels hot when I check. Because of where it's placed it should also be cooled enough from the left side fan at standstill. I always put it in neutral at lights etc, it gets hotter if it's in drive with the brakes applied.

Titch LS · June 6, 2015

Swop the radiator for a new one. Its an easy DIY job and not too expensive either if you shop around. It's good preventative medicine.

The-Acre · June 6, 2015

Swop the radiator for a new one. Its an easy DIY job and not too expensive either if you shop around. It's good preventative medicine.

In all honesty I think that's the best thing to do. As I said, it also reduces the risk of a future radiator leak. In hindsight I probably should have done that myself, in fact I may still do it at some point should I keep the car for a while, especially as my radiator is 13 years old.

tonyflynn1 · June 9, 2015

So not all Lexus rads fail the Valeo mixing way. - (Now there was a case for a class action when there was an epidemic of failures some years ago. It's possibly still happening)

http://www.ebay.co.uk/itm/2004-LEXUS-LS430-AUTO-BLUE-/231583901172?pt=LH_DefaultDomain_3&hash=item35eb79e5f4

Driving home one evening a few months ago, one of the transmission cooler hoses parted company with the radiator and dumped all of the automatic transmission fluid.

........

Being picky, the goal is really transmission oil temperature maintenance, so surrounding transmission oil pipes with rad temperature liquid is a good thing.

It could be said that keeping the oil temperature low is not that good an idea. A UK winter, driving in below zero temperatures plus wind chill; but don't ask me what the alternative is for us hapless owners.

Time to come clean Gents, this was my car.

The-Acre · June 9, 2015

So not all Lexus rads fail the Valeo mixing way. - (Now there was a case for a class action when there was an epidemic of failures some years ago. It's possibly still happening)

http://www.ebay.co.uk/itm/2004-LEXUS-LS430-AUTO-BLUE-/231583901172?pt=LH_DefaultDomain_3&hash=item35eb79e5f4

Driving home one evening a few months ago, one of the transmission cooler hoses parted company with the radiator and dumped all of the automatic transmission fluid.

........

Being picky, the goal is really transmission oil temperature maintenance, so surrounding transmission oil pipes with rad temperature liquid is a good thing.

It could be said that keeping the oil temperature low is not that good an idea. A UK winter, driving in below zero temperatures plus wind chill; but don't ask me what the alternative is for us hapless owners.

Time to come clean Gents, this was my car.

So do you know what actually caused the failure, was it corrosion?

tonyflynn1 · June 9, 2015

It was definitely corrosion, the metal pipe from the radiator was still attached to the rubber hose.

The-Acre · June 9, 2015

It was definitely corrosion, the metal pipe from the radiator was still attached to the rubber hose.

Did you loose the radiator coolant as well?

cruisermark · June 10, 2015

reading this with interest guys - 2 questions

1) Tony would you say the corrosion was from outside to inside i.e caused by road moisture.salt grit etc?

2) when we talk about replacing the radiator we are talking about the small ATF radiator which i assume is sold as a seperate part t the main radiator?

The-Acre · June 10, 2015

reading this with interest guys - 2 questions

1) Tony would you say the corrosion was from outside to inside i.e caused by road moisture.salt grit etc?

2) when we talk about replacing the radiator we are talking about the small ATF radiator which i assume is sold as a seperate part t the main radiator?

As far as I know, if it is possible to buy the cooler part alone, it would only be a main dealer part. For that reason it would make sense to buy the whole thing, which would probably work out cheaper anyway. If there's corrosion at the bottom, it surely follows that the top isn't far behind. A complete radiator can be bought for £85 upwards.

cruisermark · June 11, 2015

reading this with interest guys - 2 questions

1) Tony would you say the corrosion was from outside to inside i.e caused by road moisture.salt grit etc?

2) when we talk about replacing the radiator we are talking about the small ATF radiator which i assume is sold as a seperate part t the main radiator?

As far as I know, if it is possible to buy the cooler part alone, it would only be a main dealer part. For that reason it would make sense to buy the whole thing, which would probably work out cheaper anyway. If there's corrosion at the bottom, it surely follows that the top isn't far behind. A complete radiator can be bought for £85 upwards.

phil do they come complete with the ATF radiator aswell? do you have a link?

Loathecliff · June 11, 2015

It was definitely corrosion, the metal pipe from the radiator was still attached to the rubber hose.
Did you loose the radiator coolant as well?

This is what puzzled me. Tony said said he had lost the fluid rather than the box taking in rad water.

I've had two epicyclic auto boxes dump their fluid onto the road and lose drive, but never did it damage the box in any discernable way.

Drag home - repair pipe (usually) - refill & drive.

I'm still using one of the cars five years on, a W124.

The-Acre · June 11, 2015

reading this with interest guys - 2 questions

1) Tony would you say the corrosion was from outside to inside i.e caused by road moisture.salt grit etc?

2) when we talk about replacing the radiator we are talking about the small ATF radiator which i assume is sold as a seperate part t the main radiator?

As far as I know, if it is possible to buy the cooler part alone, it would only be a main dealer part. For that reason it would make sense to buy the whole thing, which would probably work out cheaper anyway. If there's corrosion at the bottom, it surely follows that the top isn't far behind. A complete radiator can be bought for £85 upwards.

phil do they come complete with the ATF radiator aswell? do you have a link?

This is just one example, there are many others. if you look at the picture you'll see the two hose connectors for the transmission fluid at the bottom, so it's the complete assembly

http://www.ebay.co.uk/itm/TOYOTA-LEXUS-LS430-4-3-32V-2000-2006-AUTO-RADIATOR-/200704223540?pt=LH_DefaultDomain_3&hash=item2ebae76934