Oil in coolant

[Hiluxforever]

You got lucky. Wow.

Yes. I have been super super stressed about this since August.

But after my bad accident on the second day of the new year I needed a break.

 

[Splat]

'Lucky' is not how I would characterize a $7,000 repair bill.

Blown head gaskets are not a common GX460 issue. Why do you think yours failed?

Did your car overheat? Did you ever change the coolant prior to reaching 100k?

 

[Hiluxforever]

'Lucky' is not how I would characterize a $7,000 repair bill.

Blown head gaskets are not a common GX460 issue. Why do you think yours failed?

Did your car overheat? Did you ever change the coolant prior to reaching 100k?

Radiator failure

heads are pretty expensive and so is the block.

A 22r headgasket done at the dealer was about 2200 or so about 27 years ago. That was a single head, not two. They also didnt have to remove the body to do it.

 

[Splat]

Radiator failure

Can you elaborate? Did you keep driving it after your temp gauge pegged?

 

[Hiluxforever]

Oh god no. Thats why my heads were not warped. Had a weird failure that wasnt allowing the overflow circuit to function correctly.

Half the folks with blown head gaskets claim no overheating observed, and because fo the placement of the temperature transducer, you may not even see the spike.

I saw 2 and immediately intervened both times.

I have never blown a head gasket before and didnt need the head surfaced. So thats actually kind of a big deal.

I use torque pro religiously to monitor OBD 2 telemetry.

I dont know the accuracy of the temp transducer. Its COV is 1.6.

 

[r2m]

Just got it back from the Dealer. With a new Starter it was just under 7k with tax.

Great news!
Looking at the big picture, $7k is a lot cheaper than having to junk you vehicle and buy a new one.
And on that note, you should be good for another couple hundred thousand miles now! Or about 10 to 15 years?
So, yeah, that was a painful pill to swallow, but better than the alternatives.

 

[Hiluxforever]

Great news!
Looking at the big picture, $7k is a lot cheaper than having to junk you vehicle and buy a new one.
And on that note, you should be good for another couple hundred thousand miles now! Or about 10 to 15 years?
So, yeah, that was a painful pill to swallow, but better than the alternatives.

Absolutely. I have had 13 other vehicles go through my hands that needed zero engine repairs, so I was overdue for a hit there.

 

[Hiluxforever]

Got up to about 9300 feet today. My overflow tank did not budget a mm.

Truck ran flawlessly.

 

[Hiluxforever]

I have been doing a lot of thinking, and I dont think my second radiator failed. I think it was the head gasket the whole time.

It got me wondering, and I would be curious to see how many people with head gasket issues also had valley plate issues and if the headbgasket failure could induce valley plate failure through excessive pressure to the gasket compound.

 

[r2m]

I have been doing a lot of thinking, and I dont think my second radiator failed. I think it was the head gasket the whole time.

It got me wondering, and I would be curious to see how many people with head gasket issues also had valley plate issues and if the headbgasket failure could induce valley plate failure through excessive pressure to the gasket compound.

Being lazy and not bothering to search, did you have a valley plate leak earlier?

 

[Hiluxforever]

Being lazy and not bothering to search, did you have a valley plate leak earlier?

Yep. Done a year ago with a timing cover reseal. My cooling system issues were an 18 month thing.

 

[Splat]

Did you ever change your coolant prior to the valley plate repair?

 

[Hiluxforever]

Did you ever change your coolant prior to the valley plate repair?

Yes, my first radiator failed at 120k and thats when my cooling system issues started. At 145k it started rolling white smoke at startup and I bought a commuter, which was then totaled out on the 2nd of January in a severe crash. Thus triggering the repair of the GX before I had all the money saved.

 

[Splat]

I've asked about your coolant change because old, acidic coolant is directly related to the gasket problems (head and valley plate) that you experienced.

Lexus recommends changing the coolant at 100,000 miles (or 10 years). Afterwards, the interval is every 50,000 miles (or 5 years).

The Car Care Nut and others suggest doing the first change at 50,000 miles.

Why is this important?

(the following is copied from AI)

Effects of Acidic (Old) Coolant​

​

Coolant contains corrosion inhibitors that maintain a specific pH balance (typically alkaline). Over time, these inhibitors break down, and the coolant becomes acidic.​

​

1. Corrosion of Internal Components​

Once the coolant turns acidic, it begins to eat away at the metals it touches. In a GX460, this primarily affects:​

• The Aluminum Engine Block & Heads: Acidic fluid can pit the aluminum surface.​

• The Radiator: It can lead to "pinhole" leaks in the radiator core.​

• The Water Pump: Acidic fluid can degrade the pump's seals, leading to premature failure.​

​

2. The "Achilles' Heel": Head Gaskets​

The GX460's engine uses multi-layer steel head gaskets. If the coolant becomes acidic, it can begin to eat through the delicate coating on these gaskets. Community data suggests that neglected coolant is a primary contributor to head gasket failures on high-mileage 4.6L V8s.​

​

3. Valley Plate Leak​

The "valley plate" is a plate located in the "V" of the engine that seals a coolant passage. Acidic coolant can degrade the sealant used here, leading to a slow, "crusty" pink leak that is notoriously expensive to fix (often $1,500+) due to the labor required to reach it.​

 

[Hiluxforever]

Yes

I've asked about your coolant change because old, acidic coolant is directly related to the gasket problems (head and valley plate) that you experienced.

Lexus recommends changing the coolant at 100,000 miles (or 10 years). Afterwards, the interval is every 50,000 miles (or 5 years).

The Car Care Nut and others suggest doing the first change at 50,000 miles.

Why is this important?

(the following is copied from AI)

Effects of Acidic (Old) Coolant​

​

Coolant contains corrosion inhibitors that maintain a specific pH balance (typically alkaline). Over time, these inhibitors break down, and the coolant becomes acidic.​

​

1. Corrosion of Internal Components​

Once the coolant turns acidic, it begins to eat away at the metals it touches. In a GX460, this primarily affects:​

• The Aluminum Engine Block & Heads: Acidic fluid can pit the aluminum surface.​

• The Radiator: It can lead to "pinhole" leaks in the radiator core.​

• The Water Pump: Acidic fluid can degrade the pump's seals, leading to premature failure.​

​

2. The "Achilles' Heel": Head Gaskets​

The GX460's engine uses multi-layer steel head gaskets. If the coolant becomes acidic, it can begin to eat through the delicate coating on these gaskets. Community data suggests that neglected coolant is a primary contributor to head gasket failures on high-mileage 4.6L V8s.​

​

3. Valley Plate Leak​

The "valley plate" is a plate located in the "V" of the engine that seals a coolant passage. Acidic coolant can degrade the sealant used here, leading to a slow, "crusty" pink leak that is notoriously expensive to fix (often $1,500+) due to the labor required to reach it.​

Everyone knows that already.

 

[Splat]

Everyone knows that already.

I was reacting to what you wrote here:

I would be curious to see how many people with head gasket issues also had valley plate issues and if the headbgasket failure could induce valley plate failure through excessive pressure to the gasket compound.

You had 3 sealant/gaskets failures (valley plate, timing cover and head gaskets) on your truck. And head gaskets are not a common problem on the 460.
I'm saying acidic coolant may be a contributing factor.