Lexus ISF coolant leaks/frequent low level

simranjit Jhita · May 16, 2022

Hi, not sure of this has been covered or asked before but i seem to be topping up my coolant frequently every week. Only reason I noticed the problem was when my car wouldn't provide heating when car idling, this is going back 5/6 years ago now after i had all the recall work done. I keep telling the garage that i have this problem but they say it's normal to lose a little coolant and it could be an air lock.

Well i was getting exhaust work done and i noticed coolant on the underside of my car....i'm now convinced there is a leak and surely Lexus surely should have picked this up on a service/vehicle check as they definitely look under the car to inspect! I've sent them an email now and see what they say but i'm unsure if anyone else has had this problem?

I have attached photos i took while the car was up in the air.

Arqum · May 17, 2022

Hey man, long time no speak. Get your Rad changed ASAP………. It’s a known weakness and to prevent anything worse happening get it done.

it could be the valley plate leak but you will see coolant near the head up top.

I suspect the rad is leaking from the join on the underside.

4969_LXS · May 17, 2022

From reading around, if heating is lost and the coolant is dripping down the transmission bell housing, which it looks like it is on image 2, it's usually the valley plate leaking.

Charliecloud · May 17, 2022

Every week is not right, where are you having it serviced ? They should have picked that leak up. Check under your engine cover to see if you can see that pink liquid stain on the valley between the heads.

BTCC_ Racer · May 17, 2022

Looks like you need radiator. Was this ever changed in the cars life?

simranjit Jhita · May 17, 2022

7 hours ago, Arqum said:

Hey man, long time no speak. Get your Rad changed ASAP………. It’s a known weakness and to prevent anything worse happening get it done.

it could be the valley plate leak but you will see coolant near the head up top.

I suspect the rad is leaking from the join on the underside.

Hey man yeh long time indeed!

I got the rad changed the first time I saw it was leaking down the radiator etc.. they did that FOC as they damaged it when replacing the water pump!

this time I’m getting it leaking underneath and nothing from top is visible!

simranjit Jhita · May 17, 2022

5 hours ago, Charliecloud said:

Every week is not right, where are you having it serviced ? They should have picked that leak up. Check under your engine cover to see if you can see that pink liquid stain on the valley between the heads.

I get it serviced at Tunbridge Wells. And for years I’ve been telling them yet they said nothing is wrong, that it’s normal etc… only at the weekend I finally saw underneath the car to notice the leak.

I’ve read a lot about valley plate on the American forums. Seems like it affects a lot of owners. Also I heard about it could be a cracked manifold?! I hope not!

simranjit Jhita · May 17, 2022

1 hour ago, BTCC_ Racer said:

Looks like you need radiator. Was this ever changed in the cars life?

Yeh got a new radiator years ago when they replaced my water pump.

BTCC_ Racer · May 17, 2022

I doubt its the manifold which will cause a leak.

Could be that the coolant as just aged and started rotting the new pipes of the rad? Get them to source the leak if its a rad get it changed asap i wouldnt drive the car to be on the safe side.

simranjit Jhita · May 17, 2022

3 minutes ago, BTCC_ Racer said:

I doubt its the manifold which will cause a leak.

Could be that the coolant as just aged and started rotting the new pipes of the rad? Get them to source the leak if its a rad get it changed asap i wouldnt drive the car to be on the safe side.

Haha bit late for that I’ve been driving it for about 4 years with this problem 😂 Lexus kept telling me it’s an air lock due to the new radiator fitted. I’ve contacted them and they will investigate. I’m inclined to think it’s a valley plate issue.

BTCC_ Racer · May 17, 2022

Fairplay - keep us updated, im fairly new to the ownership of a ISF. First thing i did was got the manifolds welded and changed the Rad.

simranjit Jhita · May 17, 2022

6 hours ago, BTCC_ Racer said:

Fairplay - keep us updated, im fairly new to the ownership of a ISF. First thing i did was got the manifolds welded and changed the Rad.

I will definitely keep you updated. Seems to be a fairly common problem in the states.

Also welding the manifolds was a good shout, where did you get this done and how much did it set you back if you don't mind my asking?

ubersonic · May 21, 2022

On 5/17/2022 at 1:33 PM, simranjit Jhita said:

I’ve read a lot about valley plate on the American forums. Seems like it affects a lot of owners.

A lot of American owners, the valley plate issue is related to issues with the north American climate and the sealant Toyota use on the 2UR-GSE valley plate, which were obviously never identified during the cars development in Japan, it's not really something you have to worry about in Europe (or at least the UK) unless you're super unlucky.

On 5/17/2022 at 1:41 PM, simranjit Jhita said:

Haha bit late for that I’ve been driving it for about 4 years with this problem 😂 Lexus kept telling me it’s an air lock due to the new radiator fitted. I’ve contacted them and they will investigate. I’m inclined to think it’s a valley plate issue.

If I've read the thread right you say you originally say the radiator leaking after getting a new water pump fitted and they replaced the radiator for free because they damaged it changing your water pump, but after this you still had a leak just not from the radiator and this has been going on for years now. Is it possible that the new water pump was never sealed properly and has been leaking slightly ever since? If they damaged the radiator when reinstalling it then a leak from the pump would probably have been masked by the leaking rad when they replaced the rad.

BTCC_ Racer · May 22, 2022

On 5/17/2022 at 8:26 PM, simranjit Jhita said:

I will definitely keep you updated. Seems to be a fairly common problem in the states.

Also welding the manifolds was a good shout, where did you get this done and how much did it set you back if you don't mind my asking?

I used a Toyota specialist it wasnt cheap but I had the work carried out along side a full service, all fluids changed, new brakes, and a few more bits and pieces.

The garage is based in Manchester.

simranjit Jhita · May 23, 2022

On 5/22/2022 at 12:47 AM, ubersonic said:

A lot of American owners, the valley plate issue is related to issues with the north American climate and the sealant Toyota use on the 2UR-GSE valley plate, which were obviously never identified during the cars development in Japan, it's not really something you have to worry about in Europe (or at least the UK) unless you're super unlucky.

If I've read the thread right you say you originally say the radiator leaking after getting a new water pump fitted and they replaced the radiator for free because they damaged it changing your water pump, but after this you still had a leak just not from the radiator and this has been going on for years now. Is it possible that the new water pump was never sealed properly and has been leaking slightly ever since? If they damaged the radiator when reinstalling it then a leak from the pump would probably have been masked by the leaking rad when they replaced the rad.

Ahh i hope so, banking on it being a relatively simple solution as the water pump seal rather than valley plate issue, either way i'm very disappointed with Lexus Tunbridge Wells as they have effectively been selling it as a simple air lock, and consuming coolant over time is normal behaviour. I've booked it in for them to look at next week.

simranjit Jhita · July 2, 2022

UPDATE:

So Lexus have diagnosed the problem as the valley plate leak. They want to replace the heat transfer unit and the sealant however the sealant is out of stock.....surprise surprise! So they put my car back together and told me to wait till it comes in stock....been like a month now and haven't heard anything from them.....i've emailed Lexus UK and basically got told to just wait and they won't get involved.

F4Fun · July 2, 2022

2 hours ago, simranjit Jhita said:

UPDATE:

So Lexus have diagnosed the problem as the valley plate leak. They want to replace the heat transfer unit and the sealant however the sealant is out of stock.....surprise surprise! So they put my car back together and told me to wait till it comes in stock....been like a month now and haven't heard anything from them.....i've emailed Lexus UK and basically got told to just wait and they won't get involved.

Got to be one of the first valley plates here in the UK?

simranjit Jhita · July 2, 2022

5 hours ago, F4Fun said:

Got to be one of the first valley plates here in the UK?

This is my thinking, they didn't even know what a valley plate was until after they did research etc... i'm just overall disappointed with Lexus, it's an expensive issue to rectify. I'm going to ask around to see if i can get the job done for cheaper

4969_LXS · July 2, 2022

That's a bit concerning they didn't know what the valley plate/heat exchanger was. Hopefully they know to be very, very careful with doing the job as it's not uncommon for direct injector connections and knock sensor's to get broken. They get brittle with age and heat cycling. They're not cheap either 😕

simranjit Jhita · July 3, 2022

15 hours ago, 4969_LXS said:

That's a bit concerning they didn't know what the valley plate/heat exchanger was. Hopefully they know to be very, very careful with doing the job as it's not uncommon for direct injector connections and knock sensor's to get broken. They get brittle with age and heat cycling. They're not cheap either 😕

Me too hope they don't break anything further, but so far everything seems all good. I'm a bit shocked they hadn't heard of a valley plate too, lets hope it doesn't affect anyone else in the UK, but I fear I not the only one.

ubersonic · July 3, 2022

10 hours ago, simranjit Jhita said:

I'm a bit shocked they hadn't heard of a valley plate too

Until now It had always been considered an issue with the north American climate, not something that effects Euro/JDM cars. So it kinda makes sense that UK dealerships wouldn't be aware of it, especially considering they only sold 225 ISFs in the UK (Lambo have sold twice as many Aventador here lol), most Lexus service staff have never seen an ISF in person.

Womble72 · July 6, 2022

Ring up Westfield motors in Rayleigh, essex, Ian or Chris (owners) Andre (one of their employees has an F) they’ve always looked after mine and there’s at least another two ISF’s they look after, only use genuine Lexus parts BUT they’re half the labour cost of Lexus and twice as good

simranjit Jhita · July 6, 2022

3 hours ago, Womble72 said:

Ring up Westfield motors in Rayleigh, essex, Ian or Chris (owners) Andre (one of their employees has an F) they’ve always looked after mine and there’s at least another two ISF’s they look after, only use genuine Lexus parts BUT they’re half the labour cost of Lexus and twice as good

Brilliant, thanks for this i will give them a call and see what they can offer me. I think it's a relatively easy fix but just a pain to get to the area! Lexus want to replace the whole heat transfer unit etc.. which is concerning for me as it leads me to believe either it's damaged and they haven't told me or they just taking the easy route out by replacing it rather than cleaning it up.

simranjit Jhita · August 1, 2022

So got this done finally....my bank account ££££'s lighter but i have a fully functioning car again. I have noticed that the cold start ticking noise has reduced slightly in noise level. Only time will tell if it definitely has fixed the problem but it all seems good so far.

I fear i will not be the only one that suffers from this problem in the UK. I strongly urge you all to keep an eye on coolant.

BTCC_ Racer · August 4, 2022

Nice one, did they change the manifolds? The tick is usually down to them. I had driverside manifold welded up. No more ticking noise. Alot of ISF out there have the famous tick! Absolute pig of a job to remove manifolds.

Did the clean and reseal the valley plate?