I Got a Great Deal On a Lexus GX 460, Now Lexus Tells Me There’s a Valley Plate Leak That’s Going To Cost $3,000 Or More

"We got a great deal on a 2016 Lexus GX 460, but now I'm not so sure it was a good idea to buy it. I love the SUV, but now it needs an expensive repair."

That's what Michelle, a nurse at a hospital in Lone Tree, told me as I was waiting for my wife to be admitted for a gallbladder surgery this week. After she learned I was an automotive journalist, Michelle told me about the great deal she and her husband got on a 2016 Lexus GX 460.

But Her Great Deal Wasn't So Great

Michelle told me she owned a more expensive Mercedes-Benz E-Class and had a $500 monthly car payment. So, she sold it, took the balance from what she owed, and paid cash for her 2016 Lexus GX 460.  

Her dad, a car salesman in Oklahoma, found the car and told her about it, and her husband flew to Oklahoma to buy it. She paid $17,000 for it, which is less than what it was selling for in Denver, CO. She loved it because she needed a vehicle with a third row and enough room to carry her furry friend. 

Despite the poor gas mileage, she loved the new large SUV, but shortly after she purchased the SUV, the 2016 Lexus GX 460 developed a coolant leak. Now her husband has to check the coolant level and add antifreeze weekly. It's a pain. 

However, now she's wondering if the great deal was a mistake.

"I took the GX 460 to Lexus, and they told me it had a valley plate leak. It will cost $3,000 or more, depending on what they find once they tear it down for inspection. I can't afford the expensive fix, so I guess I'll keep adding coolant." 

How common is the valley plate leak issue on the Lexus GX 460?

It is a common issue with the GX 460, the Toyota Sequoia, and the Toyota Tundra truck.

The coolant leak issue in Lexus GX 460s involves the valley plate leak. This leak occurs in the engine valley, often near the intake manifold, and can be difficult to pinpoint. The leak may be caused by a faulty seal or gasket in the valley plate, which is designed to cover a coolant passage. 

Additionally, the radiator itself can leak, typically at the connections between the plastic tanks and the core, especially after high mileage, as seen on a post on Reddit. 

Elaboration:

• Valley Plate Leak: The Lexus GX 460 has a valley plate underneath the intake manifold that houses a coolant passage. Over time, the seal or gasket holding this plate can fail, leading to coolant leaks. 
• Radiator Leaks: Radiators in the GX 460 can develop leaks, particularly at the connections where the metal core meets the plastic tanks. 
• Diagnosis: To diagnose the cause of a coolant leak, it's important to check the engine valley for signs of coolant and the radiator for cracks or leaks. 
• Solutions: Repairing a valley plate leak involves replacing the seal or gasket. Radiator leaks may require a complete radiator replacement. 
• Preventing Future Leaks: Regular coolant flushes and replacements, as well as proper maintenance, can help prevent future leaks, especially in older vehicles. 

What are other Lexus GX 460 owners experiencing?

Reddit user gmoragus says, "Oh, the infamous valley plate leak. Probably the 'only' major issue in these V8 engines. I took my 2011 to several shops in the SLC area, and they all refused to service the vehicle. I had to go to a local Lexus dealer. It took a lot of willpower to take it to a dealer. But they did a good job. The total cost was $1700. No leaks reported after the service. The vehicle now has 170k miles."

Another post on Reddit from jl938206 says, "I have a 2018 GX 460 with 46,000 miles. My water pump already went out, and I am in the middle of getting my valley plate resealed (dealer quote is $3,400). I also replaced the rear control arms because the rear suspension made noises over bumps. That replacement didn't do anything, and I just learned to live with the noise. I bought mine in 2021 with 22k miles on it, do all regular maintenance, and baby the thing."

What About the Toyota Sequoia?

The Toyota Sequoia and other vehicles using the 5.7-liter V8 engine (like the Tundra and Lexus GX 460) can experience a valley plate coolant leak. This is a common issue, often due to FIPG (Final Install Plastic Gasket) sealant failure on the heat exchanger located in the valley plate area. 

What Should Lexus GX 460 and Toyota Sequoia Owners Do?

While some experienced DIYers may attempt the repair themselves, it's a complex procedure and often best left to a trained Lexus or Toyota service technician. Or, you keep adding coolant and hope it doesn't worsen over time like Michelle. However, it's important to note that ignoring the coolant leak can lead to overheating and potential engine damage.

How About You?

Are you a Lexus GX 460 or a Toyota Sequoia owner dealing with a coolant leak? Share your experience by clicking the red Add New Comment link below.

Check out my Lexus RX 350 story: So, I Bought a New Lexus RX 350 Just to Get the 360 Camera, Now I Have a $770 Car Payment, and I’m Wondering If it Was Worth It

I am Denis Flierl, a Senior Torque News Reporter since 2012. My 30+ year tenure in the automotive industry, initially in a consulting role with every major car brand and later as a freelance journalist test-driving new vehicles, has equipped me with a wealth of knowledge. I specialize in reporting the latest automotive news and providing expert analysis on Subaru, which you'll find here, ensuring that you, as a reader, are always well-informed and up-to-date. Follow me on my X SubaruReport, All Subaru, WRXSTI, @DenisFlierl, Facebook, and Instagram.

Photo credit: Denis Flierl