I contacted the service manager to explain the coolant level is still going down. They will take another look at it next week.

 

Follow up:
Dropped off my 2020 for the 5,000 checkup. On service drive it was, of course, reeking of coolant smell.
Advisor was shocked at the potent smell. Thanks to this forum, I advised him of the speculation that it is a valve in the heater-a/c core or a leaking head gasket. The smell pulses very strong every 11 to 16 minutes. Happens every time I drive it.
Advisor Is Pursuing it with Lexus/Toyota next week.
I expect him to say: Yes problem, no cure. Then I will take it in every month to complain of the coolant smell—trying to create a string of constant complaints til Toyota/Lexus comes up with some cure.
More follow-up later.

 

I still regularly smell coolant outside the car when the car is warmed up, however the coolant level does not drop anymore so I don’t even mention it anymore. An ES loaner also smelled like coolant so it may actually be “normal”.

 

Follow up:
Today, shop foreman asked me to drop by and go over a complete engine inspection while it is up on a lift. Also, the shop Tech guy in charge of TIS said he's been complaining about this to Toyota/Lexus since 2018.
Preliminary phone call to Lexus produced a TAC number. "The closed coolant system is venting." Nobody at dealership is satisfied because the smell is horrendous.
I said, "Fine, show me the vent." Silence. Waiting on the engineer who designed the cooling system to get back on that part.

Several ideas to pursue came out of this "Stage One" meeting of minds:
1. During the Fall of 2020, dilute the antifreeze with a large amount of distilled water (50-60%). 2. Re-program ECU for a cooler operating temp, drop in a cooler thermostat. 3. Find the "vent"; use a charcoal canister to suppress the fumes. The street rodder/road racer in me came up with these, with #1 being a great direction to move in. The fact that I can actually create the smell through my daily driving routine is significant. And because I idle so much, I have chronicled the smell occurring every 11-15 minutes.

At least no one used the lame "assembly coatings burning off". I have had antifreeze leak onto and burn on the headers of my old Shelby--I know what I smell...burning coolant, not steaming coolant.
There's consensus that the heater core and coolant routing through the valving at the rear of the passenger-side cylinder head is NOT to blame.

Gonna take the loooong road to get this stopped. An amazing $75K sedan with powerful bi-turbo six cylinder. Like a pretty face with an unstoppable really bad fart (coolant burn) problem.

I will DIY it with engineers and tech folks as long as they listen...

Car still in the shop.
Prof

 

The cooling system on this car is complex to say the least. Intercooler, two coolant reservoirs (caps on each), and a "water control valve" that also has a cap. Many many hoses and pipes. But glycol coolant doesn't smell really bad unless it is burning.

 

Did you already add UV dye in large amounts? The point of burn or leak or whatever will build up dye residue and may allow you to find the real issue

Its a last resort option I use if a car simply won't show me any sign of where coolant is going and the exhaust doesn't show it burning and oil tests clean. It's "expensive" but I'm sure a 500 owner won't care about $40 unlike some of my customers.

I would suggest at this point check every single coolant drain and air bleed screw on the block, coolers, rad, etc, top off all reservoirs to spec when fully cold, if you have any electric pumps anywhere then turn them on when doing this to move any air out, and then pressure bleed the engine and cooler loops. Then wash the entire engine bay to remove anything that is UV reactive. After that's done and you are certain all air is removed and all drains/vents are sealed like they should be and the level at each rank is correct then add three bottles of dye to the engine and one to the cooler(s) and then drive it a decent bit with as many hot/cold cycles you can to see where the dye appears.

Then you can determine if the parts the dye is appearing on are these alleged vent assemblies or if there's a leak. Use a strong light in a garage with the lights off to make it easier, after it's confirmed fixed change the coolant if you want to.

 

THE “LS STINK” COOLANT SMELL IS CURED!
CONCLUSION:
I will post this to everyone, knowing some of you will find the information either boring, mis-informed, or insufficient.

These two photos will be referenced as I proceed. One is my Lexus service paperwork, the other is the over-flow of black flecks and other contaminates in the factory-installed coolant.




My background: 50 years working on cars, RVs, boats, street rods, restoring vintage Trans Am era cars, technical scrutineer for Formula 1 Teams, and regular road racer with the SCCA.

In my last post, I mentioned that I requested Toyota/Lexus to conduct a compression test, head gasket inspection, note vent location(s), and have the lower plastic panel to be removed permanently.

Friday, after two weeks in the shop, my car was returned to me. Again, I was able to visit with the shop manager in Plano, Texas, for a 45 minute Under-the-car update on the situation. I have included a picture of the paperwork so others can pursue the TAS case # in the Toyota/Lexus database.

Background: Here in Texas, decorative engine covers are a VERY terrible idea. I toss them in the attic on my first day of ownership and return them to the car years later if I am trading it in. Lexus engineers say the upper u-shaped covers are for decoration (serve no other purpose—and traps bad smells!); the lower plastic cover only prevents turbulence from causing the hood to flex in the low pressure area near the windshield. So yeah, that one is now tossed in the attic too. But it tells a story...

Here we go...
1. A few basics I learned: the passenger side coolant tank is for the engine block cooling/driver’s side is dedicated for the turbos. Each separate cooling system has its own electric water pump. The vents for the cooling system are a small slot cut into the bottom of the each coolant tank’s stem. (Remove the small black caps to see—gotta look real close); the little black cap covers most of the venting slot. The large flat softball size device front center is the complex electronic engine thermostat with internal gearing and gates that constantly vary the flow of engine coolant back to the radiator. Two drains are on the engine coolant side: one at the base of the radiator, one at the center of the engine front (where old-school timing covers would be).

2. My lower cover had chalky residue and red burned coolant stains. At my request, Lexus sent this off to a lab. It came back as a contaminant with small black flecks of junk in the factory-installed coolant. You can see it in the picture. I could see the chalky substance’s path on the side of the cover that faces the road. If you get under your car with a mirror and a good light, you might be able to see (mine was on a lift at the dealership). I think if you have the chalky substance, you have a problem.

3. Lexus flushed my complete system TWICE before the contaminate was eliminated. They also replaced the coolant tank and caps for the engine coolant.

4. Bottom line: I am told that at the factory, the cooling systems of LS500’s are 1. getting over-filled 2. with contaminated coolant. Also, the “engine” coolant tank’s vent stem should have a 1/4” hose dropping down about 20” to chassis-level in order to route stinky coolant fumes away from engine area (my cure, not Lexus endorsed).

5. (I am told this is important) Though I have my car back, my TAS case is still “open” with Lexus. Obviously, they are wanting to see what happens with mine and if other owners have the same chalky residue from contaminated engine coolant and excessive overflow.

I can report that for the first time, I am able to drive my car normally on the highway and around town without smelling any trace of coolant. With the lower cover off and stored in my attic, I can detect a faint increase in road noise in the form of wind turbulence (turn up the disco music one notch), but so far, the hood does not vibrate at the base of the windshield. I will test that on my next trip to Austin, TX where I can go flat out, way into triple digits, on the toll roads.

This is my last posting on this issue because mine is finally and gloriously fixed !!!!!!!!!!!!!!!!!

Paul
Dallas TX

 

Paul, HATS OFF TO YOU!.... for your determination to have this problem addressed and a solution identified.

I started this thread about a year ago, about a week after purchasing my LS 500 and pursued this problem with Lexus, which continuously denied there was a problem, time and time again, every time I took my NEW LS500 in to complain about the smell.

I’m not going to make excuses or bore you with my lack of results. Needless to say, this LS 500 community experiencing this problem (for sure ME), THANK YOU!

I will be contacting my dealer in the morning.

 

so what exactly needs to be done here, flush the system a bunch of times, change the caps, and attach a long hose to the tank stem?

 

Please note: My research might be "informed" (tainted) by what I call the "LexusTexas2-step", which is the removal of the heat-trapping upper and lower decorative engine bay AND engine covers. Get rid of all the crappy plastic covers!
I have NOT routed a 20" rubber vent hose out the bottom of the engine bay YET. That's my next DIY if this doesn't go away entirely. I am currently pleased with the results from my dealership and will not need to. If something hot needs to "normally" vent to the atmosphere, then the shop manager said venting it away from the upper engine area directly under the hood would be a great idea.

 

is this pretty easy to do? im seriously interested in either this car or the ES. New. How are you liking the low headroom space in the LS? Im a short guy and even I felt a little claustrophobic in the LS. I heard the ES head better headroom.

 

I've owned the LS and had a ES loaner. To me they have roughly the same roominess. The ES might have an inch or 2 more rear leg room. The LS feels way more substantial and solid though.

 

Three weeks...1,400 miles
No burning coolant smell at all, ever. A little cooler outside, but same aggressive driving style.

 

i have a 2014 lexus gs 350 f sport (Great car but im bored as hell with it ) and want to trade it for a 2018 LS 500 f sport or base. Do you know if LEXUS/ TOYOTA corp. has finally launched a recall for that coolant issue you had ?

 

No, but the fact that Toy/Lex left my case in “open” status indicates that other shop managers can see into the cure. During test drive, make sure you mimic running errands to dry cleaners and drive-thru. Wait for the smell near the passenger side front wheel opening.

I did the same trade (GS to LS) and I am very pleased with it...finally.