Lexus LS430 - Water Pump Leak

Lexus_2023 · August 13

My car recently had its annual service, including a brake fluid change. During the inspection, the mechanic noticed that the coolant level was slightly below the minimum mark, which I had also observed. Initially, I assumed this might be due to evaporation, but upon further investigation, the mechanic discovered a small leak in the water pump and recommended replacing it. Since the water pump is connected to the timing belt, he suggested replacing both. This car is a pre-facelift model, and the timing belt, water pump, and drive belt were last replaced in 2015, with the radiator and drive belt being changed in 2020. I’m a bit surprised that the water pump is leaking after just nine years. I'll monitor the coolant level over the next few days to determine if this repair is necessary. Please let me know your thoughts on this...

GEN · August 13

Not quite on topic but my radiator(replaced by Lexus 3 years ago) has apparently developed a small leak! I know they don't build them like they used to but 3 years for a radiator! (Probably long enough that the replacement will be on my tab).

Malc1 · August 14

Gen hi …… that’s so disappointing ……. and Lexus would have used a proper OEM one too and charged you mega bucks I’m sure ……. very sad

Malc

Malc1 · August 14

and CV ……,,, you’re Ls430 …… what’s the mileage covered since the cambelt and waterpump replaced in 2015 ?

They’re replaced together being in the same “ impossible “ location

They say cambelt life is maybe 10 years / 100k miles but it’s a hugely expensive long hours job to replace but good preventative maintenance …….. and if the cambelt goes pop then your car’s going to be an economic write-off sadly with engine destruction ……. it’s as simple as that sadly

Malc

Lexus_2023 · August 14

@GEN I agree with you and have been thinking about the cost of OEM parts from manufacturers. If the quality of OEM parts isn't the same as the originals, why should we pay more instead of opting for third-party alternatives? The issue we face is the high labour cost, and we'd prefer to avoid redoing the work by using reliable OEM parts directly from the manufacturer. However, these days, I'm uncertain whether paying the extra for manufacturer OEM parts is really worth it.

GEN · August 14

6 minutes ago, Lexus_2023 said:

@GEN I agree with you and have been thinking about the cost of OEM parts from manufacturers. If the quality of OEM parts isn't the same as the originals, why should we pay more instead of opting for third-party alternatives? The issue we face is the high labour cost, and we'd prefer to avoid redoing the work by using reliable OEM parts directly from the manufacturer. However, these days, I'm uncertain whether paying the extra for manufacturer OEM parts is really worth it.

I'm on my third Lexus in over 10 years and I suppose I've been lucky in that I have only used Lexus dealerships (Woodford and now Sheffield) and have found them to be entirely satisfactory (knowledgeable, helpful and efficient) and I don't blame the dealership for the radiator. As you know Lexus won't fit parts they don't supply and so to use non-OEM parts I would have to go through all the potential trials and tribulations of finding a equally satisfactory independentwhich I think is a tall order. My previous experience was with VW and Porsche dealerships and they were far from satisfactory...

Malc1 · August 14

And your Ls600 is such a rare car and finding an Indy mechanic to work on it might be challenging too …….. thankfully your visits for repairs should be infrequent …… but then again, you are driving an amazing car 👍

Malc

Lexus_2023 · August 14

2 hours ago, Malc1 said:

and CV ……,,, you’re Ls430 …… what’s the mileage covered since the cambelt and waterpump replaced in 2015 ?

They’re replaced together being in the same “ impossible “ location

They say cambelt life is maybe 10 years / 100k miles but it’s a hugely expensive long hours job to replace but good preventative maintenance …….. and if the cambelt goes pop then your car’s going to be an economic write-off sadly with engine destruction ……. it’s as simple as that sadly

Malc

@Malc1

Please find the details below.

Year 2015 - 66,000 Miles - TB, WP, Spark Plugs, Drive Belt and associated components
Every year annual Service with appropriate maintenance schedule (Not even single year missed!)
Year 2020 - New Radiator, Coolant Change and Second drive belt change
Year 2024 - 119,500 Miles - Intermediate Service with Brake Fluid change (BF is due this year) - Done now.

Year 2025 - Next TB, WP etc is scheduled (I have been planning to do that next year).

I agree with you; driving this amazing car brings me so much satisfaction (We did a 4-hour drive on Sunday, and it was incredibly smooth and calming). So, I was a bit surprised to find out that the water pump has started to leak slightly.

Just placed an order for new Lexus WP, TB and WB. Collecting other parts information now!

Lexus_2023 · August 14

31 minutes ago, GEN said:

I'm on my third Lexus in over 10 years and I suppose I've been lucky in that I have only used Lexus dealerships (Woodford and now Sheffield) and have found them to be entirely satisfactory (knowledgeable, helpful and efficient) and I don't blame the dealership for the radiator. As you know Lexus won't fit parts they don't supply and so to use non-OEM parts I would have to go through all the potential trials and tribulations of finding a equally satisfactory independentwhich I think is a tall order. My previous experience was with VW and Porsche dealerships and they were far from satisfactory...

Yes, having a competent mechanic to investigate and repair any issues is crucial. We go to an independent specialist in Japanese cars called Japex in Kings Langley. They’re reliable, professional, knowledgeable, and always helpful. The service manager, Danny, knows every detail about these cars. It's amazing how he remembers both the customers and their vehicles!

GEN · August 14

4 hours ago, Lexus_2023 said:

Yes, having a competent mechanic to investigate and repair any issues is crucial. We go to an independent specialist in Japanese cars called Japex in Kings Langley. They’re reliable, professional, knowledgeable, and always helpful. The service manager, Danny, knows every detail about these cars. It's amazing how he remembers both the customers and their vehicles!

Sadly I'm almost 200 miles North of Kings Langley...

Lexus_2023 · August 24

Just a quick query. When we replace the timing belt (TB), we will include TB idler, TB tensioner, and water pump etc.

I'm considering including the drive(serpentine) belt since the labor cost would be the same. Given that both the drive belt's idler and tensioner have been running for two decades+, would it be advisable to replace them as well?

Malc1 · August 24

I’m presuming you’re saying that the simpler drive serpentine/ fan belt is included in the price ? Not additional cost ! Other than maybe the very few ££ that simple belt costs

I don’t know about the other you mention …….. on my 95 Ls400 at 250k miles I don’t think they’ve ever been replaced tbh 🤔

My last cambelt ( timing belt, ) and all that challenging stuff I had dealt with at @ 205k miles ……. it’s a huge expensive job for sure but ESSENTIAL preventative maintenance

Malc

Lexus_2023 · August 24

2 hours ago, Malc1 said:

I’m presuming you’re saying that the simpler drive serpentine/ fan belt is included in the price ? Not additional cost ! Other than maybe the very few ££ that simple belt costs

I don’t know about the other you mention …….. on my 95 Ls400 at 250k miles I don’t think they’ve ever been replaced tbh 🤔

My last cambelt ( timing belt, ) and all that challenging stuff I had dealt with at @ 205k miles ……. it’s a huge expensive job for sure but ESSENTIAL preventative maintenance

Malc

Thanks @Malc1 I assume the drive serpentine/fan belt will need to be removed to replace the cambelt and water pump in the Lexus LS 430. Therefore, the drive belt replacement shouldn't require additional time, so the labor cost should remain the same. However, I may need to confirm this with the garage.

My question is: When we replace the cambelt (timing belt), we typically also replace the timing belt idler, tensioner, water pump, and related components. However, when it comes to replacing the drive belt, very few people mention its idler and tensioner. So, I'm wondering—if we replace the entire cambelt and its associated parts every 10 years and the drive belt every 5 years, why don't we replace the drive belt's idler and tensioner as well? These parts have been running for over 20 years now without replacement.

Malc1 · August 24

I don’t have an answer for you but hopefully another member here does

Someone should be along soon to advise

Good luck

Malc

The-Acre · August 24

3 hours ago, Lexus_2023 said:

Thanks @Malc1 I assume the drive serpentine/fan belt will need to be removed to replace the cambelt and water pump in the Lexus LS 430. Therefore, the drive belt replacement shouldn't require additional time, so the labor cost should remain the same. However, I may need to confirm this with the garage.

My question is: When we replace the cambelt (timing belt), we typically also replace the timing belt idler, tensioner, water pump, and related components. However, when it comes to replacing the drive belt, very few people mention its idler and tensioner. So, I'm wondering—if we replace the entire cambelt and its associated parts every 10 years and the drive belt every 5 years, why don't we replace the drive belt's idler and tensioner as well? These parts have been running for over 20 years now without replacement.

It's obviously good practice to replace idlers and tensioners, especially after so long, the difference being that the aux belt won't cause severe engine damage if it or its components fail like a cam belt would. It's also worth mentioning that replacing the aux belt on the 430 is simplicity itself, taking less than 10 mins!

Lexus_2023 · August 25

Thanks Phil. I’ve been thinking the same thing. Let me check with the garage first. If they charge extra labour costs, I’ll wait and do the serpentine belt next year when it’s due. Otherwise, I’ll replace it this year since it would only involve the cost of parts.

The-Acre · August 25

13 hours ago, Lexus_2023 said:

Thanks Phil. I’ve been thinking the same thing. Let me check with the garage first. If they charge extra labour costs, I’ll wait and do the serpentine belt next year when it’s due. Otherwise, I’ll replace it this year since it would only involve the cost of parts.

The aux belt has to come off to replace the cam belt, but removal literally takes 1 minute, You have a car with one of the finest engines ever produced, so getting your water pump leak sorted and the security of a cam belt replacement will give you much peace of mind.

In my many years of various LS ownerships, the only issue with any engine was a coil pack on an early MK2. Hang on to what you have and look after it, there really is nothing else out there like it, and I believe it ended with the demise of the LS430, and every LS before it shares the same honour!

steve2006 · August 25

I bet it was the passenger side coil pack Phil, located in the most challenging position and gently heated by the exhaust manifold 😀

The-Acre · August 26

14 hours ago, steve2006 said:

I bet it was the passenger side coil pack Phil, located in the most challenging position and gently heated by the exhaust manifold 😀

Correct!