Acrad

OP: How far away are you from Lexus powertrain warranty expiration? This will be 6 years from first sale date or 70k miles within that 6 year period. Factor that in as you pursue resolution to issues here.

or do you have an extended warranty as well?

xychromo

6 years powertrain warranty expires at the end of this month, so time is of the essence! I have an appt at the Lexus dealer tomorrow morning so will at least have a record of this issue before the warranty expires. I did take it to the same dealer last month for the fuel pump recall and also paid extra for an inspection since I had just purchased the vehicle (from a diff out of state dealer) and wanted to get an all clear since my warranty is due to expire. The inspection supposedly included looking at the coolant, which they checked as 'passed inspection', so you can bet I'll be bringing that up during my visit!

xychromo

Update: So I'm currently at the dealership and have finished talking with the master tech about my coolant issue. First of all, and most interesting, the coolant color was not an issue. It is an optical illusion of the coolant against the black background of the radiator opening. The tech actually pulled some coolant out with a tester and it shows as bright pink. He then topped up the radiator with some coolant from a bottle and it again appears orange/brown in the radiator. Weird, yes, but now I know that the color isn't an issue.

Secondly, as for the coolant level, they ran a pressure test and found no leaks. The tech seems to think that the low level was likely due to the fact that the car had the timing cover reseal service 40k miles ago. There may have been some air in the system after they replaced the coolant at that time and it wasn't topped off since then. Fast forward to today where I notice the low level. He also didn't seem to think that the low level would be due to the coolant valley leak as he didn't see any evidence of this, although didn't take a close look at the rear of the engine. He said that in his experience, if he saw that, it would be in an older, higher mileage model and very rarely in a GX. His suggestion was to continue to monitor the coolant level and if it drops considerably in the near term, to bring it back in. At least I now have a baseline with Lexus on this in case I need to return to address this same issue.

Overall, I was happy that I had face time with the tech, he answered all my questions and didn't give me the runaround. The dealer also didn't charge me for the visit, I was expecting a diagnostic fee, so that was a nice surprise, and they even washed the car for me! So kudos to the dealership on this one.

Acrad

IMO: That seems like a long period of time since repair for it to finally burp out 2 quarts of air space. You should know soon enough if their diagnosis was correct or not.

xychromo

Agreed, however I don't know how long it's been low on coolant for since I've only had it a month. The last lexus service on record was at 54k (I purchased at ~64k), which notes a 'multipoint inspection', including a check of fluids. Losing 2qt in 10k rather than over 40k would be more alarming assuming they actually did check the coolant level. So I will just continue to watch the levels closely and see if there are any significant changes in the short term. Another possibility the tech mentioned was a malfunctioning radiator cap which may be off-gassing more than it should. I may just get a new one since that is an easy and cheap maintenance item.

KYGX

I have a similar issue. Bought my 2011 with 140k the last day October. Had it checked out by a friend who is a good mechanic. He added coolant to the reservoir. Had my first oil change about 2 weeks ago, they noted they added coolant to the reservoir. Popped the hood today just to do it, and noticed there is no coolant in the reservoir. I can see no evidence of leaks, and I'm quite worried about this. I guess I will begin with having the coolant pressure test done as soon as I am able to get it in.

Acrad

Any residue around the coolant recovery tank lid? Another cheap thing to do is replace your radiator cap to ensure you have a good seal too that could allow boil off

Radiator cap
PN: 16401-30020

KYGX

Thank you so much for the part number. I'll investigate around the recovery tank lid, and I'll go ahead and order a new cap too.

KYGX

Also, I have noticed my GX has white exhaust on startup, but so did an almost new 2019 I test drove before buying my 2011.

Kandabear

Check out this thread.
https://www.clublexus.com/forums/gx-...te-leak-3.html
Scroll to the bottom.

I had the same issue. No visible leak, but losing coolant.
Lexus master tech looked at it, did pressure test and said it was fine.

No. It was not fine.

I "scoped" the underside of the intake and there was in fact the valley plate leak. This did NOT show a leak under the dealership pressure test.
I Showed the tech the photos from the scope and it was repaired under my extended warranty.
Have them look again. Or better yet, get a cheap flexible inspection camera and look yourself, take photos, and take them to the dealership. That's what I had to do.
This is not an easy or cheap repair.
That much coolant loss from lack of a system burp is not possible.

xychromo

Thanks for the info and the link. I am encouraged that after almost 1 month and 900 miles, the coolant level has not moved in my expansion tank. However I'll get my hands on one of those scopes and take a closer look to put my mind at ease. Is this type of leak more common in the earlier versions of the GX460, i.e. '10-'13, or is it just more common is higher mileage versions, regardless of year?

xychromo

@Kanda, what size of boroscope would you say to use for this? I'm looking at a relatively inexpensive version online and it has a width of 8mm, would that be too wide?

Kandabear

This is the one I used. It is also 8mm head diameter.
it will NOT fit under the manifold to inspect everything, but it was good enough in my situation to see what I needed to see in the lateral recesses around the valley pan.
It was an Amazon purchase. I think I paid 25 bucks or something super cheap. Interfaces through Android via WiFi and an app so it's easy to take photos.
smaller one would definitely be better for this purpose but the 8mm did what it needed to.
Good luck!

KYGX

I'm going to pickup a borescope to see what I can find. I replaced the the radiator cap, but I've filled the reservoir 3 times and it's empty again. Still no coolant smells or visible leaks. I'm assuming it's nothing a coolant valley gasket replacement won't fix; unfortunately.

xychromo

refilled 3 times over what time frame? I've been checking my level weekly since the last refill (about 5 weeks ago) and my level hasn't changed. My boroscope arrives on Thursday so will check again then.
Good luck to you!