skeener

Maybe the head or deck is warped or cracked? No head gasket is going to fix those things.

alfreema

Asked them about whether the head would need to be machined or anything and the service tech assured me they test it somehow. Can't remember how he put it but part of the Lexus protocol is to test them for flatness or something?

IanG

Exactly, head gaskets usually fail for a reason that is usualy a warped head .
This is rare on the GX but any engine can experience a head gasket failure from a warped head.

skeener

Well that leaves a crack, defective gasket, or faulty installation then.

alfreema

With these symptoms can it be anything other than a head gasket issue? Computer issue, or something crazy that was misdiagnosed or something?

If it was a faulty installation, then that's twice. You'd think once it was returned they'd make darn sure to get it right the second time.

Gerf

Did you have any symptoms of a head gasket problem like excessive smoke from the exhaust/milky oil/overheating/coolant reservoir overflowing ??

skeener

If the offending cylinder looked steam cleaned, that would tend to corroborate a coolant leak via head gasket,

alfreema

Before I agreed to the head gasket job, I did have whiteish smoke from the exhaust, (kinda like when you run seafoam through a tractor but not nearly as bad). The oil never showed milky. The car never overheated. The technician said they saw coolant in the heads, but I got the impression it wasn't too bad (though, any is bad enough I suppose?). Coolant reservoir never overflowed.

Gerf

I can understand how someone might connect that misfire code with a head gasket issue but if that were the case the engine should be running rough all of the time and clearing the code/codes will not make it run smooth even for a short time.
That s/plug looks like it may be burning oil or not firing properly or has never been changed.

It's been about a year since your problem started and last November for the second repair right? how much coolant have you had to add in total to now? If the head gasket is leaking internally or externally you will lose coolant unless you're not driving the vehicle.

jakemt

I just had a synthetic oil change as well on my 2012 GX460. Right afterwards, I went into a car wash which was next door to the garage, and these same codes show up but the car now barely starts and then dies. I hope it's not the same situation like yours. Can you please provide some details as to how they destroyed your original engine with a routine oil change? Thanks.

alfreema

Interesting. Well after the head gasket job, when the codes came back, clearing the codes did not help. But it did help initially prior to the head gasket job.

I didn't drive it much and kind of sat on it, not sure what to do -- spend gobs of money on a head gasket, get a new engine, take it to an indy, take it to a certified service center. I was just kind of paralyzed. I work from home so it wasn't being driven hardly at all from May until November (I think) when I finally decided to just spend the money on the certified service center.

It has definitely been maintained per Lexus scheduled maintenance, but I don't know at what interval those would get swapped? It was kind of "wet" and charcoaly, if I remember -- been awhile now.

Trying to recreate the timeline ... I think I took it in in November maybe? They had it for two weeks. Then I got it back and it took maybe two or three months to throw the code again. I scheduled up something a week out so I could get a loaner car (maybe February) and this time it fired the code just a few weeks after getting it back. It does run rough now (kind of has the sound of a leaking exhaust header), and resetting the code doesn't help one bit. I have it scheduled to go back in next Thursday (first day they had a loaner available).

wildcat767

I'm having the exact same issue too. The Lexus dealer already fixed it twice with a new plug and coil and it came back again. I noticed smoke out the exhaust on cold start but it went away. I'm trying the PCV valve next. I heard that can cause these issues too.

OP: any update on the fix for yours?

Thanks!

alfreema

Just dropped it back off at the certified Lexus service center after two head gasket repairs (second was a warranty by Lexus factory because they thought it was a bad gasket). Returning it for a third head gasket job is unprecedented so I am waiting to hear what the next step is.

wildcat767

Wow. That is not encouraging at all! Sorry to hear this. I'm hoping mine isn't a head gasket. Did you have smoke out the exhaust all the time or just at startup?

alfreema

Yeah, I didn't want to be the bearer of bad news. Sorry!

I only had smoke at start up.