Have any 5th Gen owners experienced a head gasket failing? This mechanic says the 4th Gen 4.0L Toyota engine (5th Gen also has) has a problem with head gasket failures over 120k miles???? I’ve never heard of this being a common failure on the 4.0L engines. My 5th Gen has 130k miles on it so this video has me a little worried. I change my oil every 5k and change my engine coolant every year (overkill I know) other than that how do you prevent this from happening? Thanks. https://www.youtube.com/watch?v=9WKUxVR7wIU&feature=youtu.be
5th Gen Head Gasket problem?
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Never heard of a problem with the head gasket in a 5th generation. Nothing you can do about it, anyways.
Whippersnapper02
Senior Member
Supercharged at 80K miles and went to 145K before my 2010 Tacoma was totaled without issues and that was with numerous full throttle runs. The early engines 05 maybe 06 did show some headgasket issues but that's almost 20 years ago.
2021nightshade4x4
New member
No one wants to fess up but the red coolant (OAT) causes gaskets to swell more than green (IAT) and compromises the good factory seal.
I remember just enough of high school chemistry to know that it’s just as bad to keep adding fresh coolant because the new stuff is what REACTS, old stuff is stable and has already gotten into the gaskets and expanded.
You’re doing a good thing for the COOLING system keeping fresh coolant in there, but those engine gaskets keep having a fresh supply of red that has not yet reacted with the gasket material and expanded further.
Like the old LLY GM Duramax trucks with 300k+ miles on them have heads done at least once. Usually at around 160k. The ones without head jobs were owner maintained (read: oil changes only) and left the original coolant in or just topped it up as needed.
Counterintuitive as all hell but makes sense when you think about it. A manufacturer would never advise you to NOT get something done - they have a vested interest in you getting fluid changes and the subsequent engine work thereafter.
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I remember just enough of high school chemistry to know that it’s just as bad to keep adding fresh coolant because the new stuff is what REACTS, old stuff is stable and has already gotten into the gaskets and expanded.
You’re doing a good thing for the COOLING system keeping fresh coolant in there, but those engine gaskets keep having a fresh supply of red that has not yet reacted with the gasket material and expanded further.
Like the old LLY GM Duramax trucks with 300k+ miles on them have heads done at least once. Usually at around 160k. The ones without head jobs were owner maintained (read: oil changes only) and left the original coolant in or just topped it up as needed.
Counterintuitive as all hell but makes sense when you think about it. A manufacturer would never advise you to NOT get something done - they have a vested interest in you getting fluid changes and the subsequent engine work thereafter.
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TOYO74
New member
Are you saying that changing coolant at specified intervals is what causes head gaskets to fail? I have never heard or read anything like that. Is this your own theory? If not, would you provide a link to where you got this info? I would be interested in reading it. Thanks
That is fascinating I’ve never heard of this but it makes sense.
Charlievee
Senior Member
Head gasket fails... Take a weekend and replace it?
2021nightshade4x4
New member
Specifically with red, yes. I wished they used green.
Hits Tacomas and 4Runners alike: Head gasket failure on 4.0 Toyota engines | Tacoma World
Here’s a good short read with pictures of what happens. It’s a GM article but all red OAT (organic) coolant behaves this way: http://www.zr1specialist.com/HAT We...at DexCool Harms the Cylinder Head Gasket.pdf
Plenty of anecdotes: Top 78 DexCool Reviews
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2021nightshade4x4
New member
The people you won’t hear from are the ones who trade before they even have enough mileage to see these kind of problems. I believe 4Runners are traded up more often than Tacomas.
For those of us in this for the long haul, 140k miles is too early for head gaskets to go. I’d expect that out of a Jag or Range Rover, but not Toyota.
I don’t want to crap on Toyota but I really need to know if flushing and switching to green will void my warranty. I am asking for future reference - I only have 1000 miles on my 4Runner LOL
I have several domestics that don’t even have a pressurized overflow tank (they have a flip cap) and have zero issues at 300k miles and are driven 10-15k miles a year each.
This style below. Not secure at all but the level has not had to be topped off since the last time it was drained. (Water pump several years ago). But it’s green so that doesn’t matter.
https://cimg3.ibsrv.net/gimg/www.ch..._dfc0ba12544d06ff3cb185fee9aa0c347a24a962.jpg
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For those of us in this for the long haul, 140k miles is too early for head gaskets to go. I’d expect that out of a Jag or Range Rover, but not Toyota.
I don’t want to crap on Toyota but I really need to know if flushing and switching to green will void my warranty. I am asking for future reference - I only have 1000 miles on my 4Runner LOL
I have several domestics that don’t even have a pressurized overflow tank (they have a flip cap) and have zero issues at 300k miles and are driven 10-15k miles a year each.
This style below. Not secure at all but the level has not had to be topped off since the last time it was drained. (Water pump several years ago). But it’s green so that doesn’t matter.
https://cimg3.ibsrv.net/gimg/www.ch..._dfc0ba12544d06ff3cb185fee9aa0c347a24a962.jpg
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Syr4RinNC
New member
I wouldnt worry about your head gasket.
This is not a common enough problem to stress over. Ive had a 95, 03 and now 08 and monitor my parents 2018.
Head gasket issues were common prior to 2005. (1st, second, 3rd gen). Vehicles manufactured 12/2005 and later are low risk for head gasket issues, assuming normal use and maintenance. As noted heat is not your friend, so dont let your engine overheat and keep an eye on the coolant. I would continue to follow the maintenance recommendations and recommended fluids.
Even with bullet proof reliable toyotas, occ issues come up with head gaskets, transmissions etc, but are relatively uncommon in comparison to other vehicles
This is not a common enough problem to stress over. Ive had a 95, 03 and now 08 and monitor my parents 2018.
Head gasket issues were common prior to 2005. (1st, second, 3rd gen). Vehicles manufactured 12/2005 and later are low risk for head gasket issues, assuming normal use and maintenance. As noted heat is not your friend, so dont let your engine overheat and keep an eye on the coolant. I would continue to follow the maintenance recommendations and recommended fluids.
Even with bullet proof reliable toyotas, occ issues come up with head gaskets, transmissions etc, but are relatively uncommon in comparison to other vehicles
Not looking to argue, but I didn't have that information fixing cars the last 10 years. Not sure I'm convinced. Also, I'm pretty sure the gaskets are MLS. How does that gasket swell?
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TOYO74
New member
Toyota Red is not OAT coolant, it is IAT (Inorganic Acid Technology). It is similar to the old "green" coolant you refer to. Don't base what happened with GM engines and DEX-COOL with Toyota engines. I don't believe the head gasket failures in the late 90'-early 2000's were due to red coolant.
Your 2021 Toyota has PINK coolant which is OAT.
I've been driving Toyotas since 1974 , have always used the factory recommended coolant and have never had a bad head gasket.
My 2016 4R has pink coolant and I trust Toyota info saying that this is the best coolant for this engine. Use green if you want, it is your vehicle.
2021nightshade4x4
New member
If it’s not fiber then it shouldn’t do it. The ones in the link were fiber over steel.
I guess we rule that out for the Toyota’s. What do we think is causing the gasket failures?
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2021nightshade4x4
New member
Good to know for the earlier ones - as for me, I guess we’ll see. I’m already planning on halving the fluid change intervals. 10k for oil is too much for my brain to accept. 5k should be ok since I’m going in for tire rotation anyway.
Just daydreaming, I wonder what would happen if I ran straight Water Wetter, LOL!
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Where_am_i
Junior Member
The head gasket issue affected the 03-05 4th gens. It was resolved with the facelift 4th gens starting in 06.
a47chuck
New member
"But the Toyota 4Runner's V6 engine is completely different from the Toyota Tacoma's. The 4Runner has a 4.0-liter V6, making 270 hp and 278 lb-ft. The only available transmission is a 5-speed automatic. So, no, the Toyota Tacoma and Toyota 4Runner don't share the same engine."
Do the Toyota Tacoma and Toyota 4Runner Have the Same Engine?
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EddieV4runnin
New member
Yeah that’s not what’s happening, besides that channel on YouTube is never accurate. They literally will make up problems that aren’t common to the vehicles. Pink or green doesn’t change anything, that’s just a dye. If you want to be accurate Asian manufacturers use OAT coolant with phosphates. American auto manufacturers like to use silicates. Phosphates based on their studies wouldn’t clog passages like silicates did. OP don’t worry about blowing head gaskets. Change out your coolant and enjoy your 4Runner. Have you ever heard of electrolysis?? Not changing your coolant will pockmark the pump and other components.
2021nightshade4x4
New member
See that’s the kind of specifics I like reading. That’s great to know. “Bob is the Oil Guy” but coolant.
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CutthroatSlam
Senior Member
260k miles on a 2014 and no head gasket problems. Really no problems other than tire balancing shakes.
FYI:
There is a difference between Toyota's red concentrate and Toyota's SLLC 50/50 Pink.
Red uses a sodium benzoate inhibitor and Pink uses Sebacic acid
Zerex Asian vs. Toyota "Pink" SLLC
However most of these non OEM pink-compatible fluids also use Sodium Benzoate like the Toyota's red.
The only aftermarket coolant I found that used Sebacic acid was Aisin's ACT002
There is a difference between Toyota's red concentrate and Toyota's SLLC 50/50 Pink.
Red uses a sodium benzoate inhibitor and Pink uses Sebacic acid
Zerex Asian vs. Toyota "Pink" SLLC
However most of these non OEM pink-compatible fluids also use Sodium Benzoate like the Toyota's red.
The only aftermarket coolant I found that used Sebacic acid was Aisin's ACT002
