2011 Lexus LX570 Intermittent Overheating

[NOVALX570]

Hi All - long time user of this site!

Proud owner of a 2011 Lexus LX570 with 233,xxx miles I bought ~1.5 years ago.

I have been having intermittent overheating issues over the last ~3,000 miles I am hoping somebody has had experience with given a local Indy shop and the Chantilly Lexus dealership both struck out.

Approx. 2 months ago, I noticed the temperature gauge slowly climb as I drove into my apartment parking garage after running a few quick errands. It ultimately climbed just up to the red line before I shut the car down (no warning lights came on). I brought the car to a local Indy shop the next day, where they ran tests on it for the next two days and said they could not identify anything wrong with the car.

I subsequently drove the car a few days later from Washington, DC to Cincinnati, OH (dumb, i know) without any issue. In hour ~7 of what would have been a roughly 9 hour drive back the temperature gauge started climbing again. I promptly pulled over and had the car towed to Pohanka Lexus in Chantilly w/ 232,1xx miles (again, no warning lights actually came on). After having the car for a few days, they escalated the issue all the way up to the lead Forman in the shop and again were unable to replicate the issue or identify a root cause.

I drove the car another ~1,400 miles until the issue happened again, in Raleigh, NC (see attached for picture). I let the car cool down and drove it back from Raleigh, NC to Washington, DC the next day with no issue.

I sent videos of the issue to the Indy shop and Pohanka Lexus and they both told me that while this is an issue and the car should be shut off when this happens, they would not be able to diagnose at this point without the issue being replicated while they have the car. I’m at a lose given that the overheating issue can take over a thousand miles before popping up again.

Has anyone ever experienced this before or have any recommendations for next steps? I don’t love the idea of driving around a car that can overheat at any moment.

 

[gaijin]

My best guess, and that's all it is, is that you may have air in your cooling system. Every time air is trapped around the temp sensor, the temp indicator rises - only to return to normal when the trapped air moves on and the sensor is in contact with coolant again.

Have you had any work done on your cooling system lately?

When your car is cold, i.e. after sitting overnight, what is the coolant level in the coolant overflow reservoir and in the radiator itself? And do these observed coolant levels change from day to day?

That's all I've got.

HTH

 

[gasman4u]

I was going to guess air lock too, but I’m second with this possible cause. When it’s fixed, please update.

 

[04UZJ100]

Have you done any work to it recently? Air pocket unlikely unless recent service/liquid change out. Recommend starting with replacing thermostat and refilling/burping the system. The system is self purging. Air pockets should not linger in it. Last time I did a full drain and fill of cooling system, it just took running it for 1 min on a slight incline to purge all air out.

 

[vipergrhd]

I'm with @gaijin on this one, and I am surprised both shops didn't make any recommendations whatsoever. You might have a slow leak combined with a sticky thermostat. I would at least do a fluid level check in the morning see if you are low every cycle fluid is going somewhere if you need to add.

 

[TeCKis300]

Intermittent issues are hard to solve. Doesn't sound like it's an issue isolated to a certain driving condition? Seems like low speed around town/apartment, and also highway travel at speed? Is it triggering after under high loads or high rpm?

When's the last time you serviced the cooling system, including changing the water pump and thermostat? At 232,1xx miles, is it due? Were OEM parts used?

I agree, it can be a thermostat sticking, impeller degrading and slipping, even failing ECT sensor? Even a leak like in the common valley plate could be a source of air pockets.

 

[gaijin]

Hey @NOVALX570 , any feedback to our questions? Any progress finding a solution?

Inquiring minds need to know.

TIA

 

[NOVALX570]

My best guess, and that's all it is, is that you may have air in your cooling system. Every time air is trapped around the temp sensor, the temp indicator rises - only to return to normal when the trapped air moves on and the sensor is in contact with coolant again.

Have you had any work done on your cooling system lately?

When your car is cold, i.e. after sitting overnight, what is the coolant level in the coolant overflow reservoir and in the radiator itself? And do these observed coolant levels change from day to day?

That's all I've got.

HTH

I did not have any work done to the cooling system before this issue arose. The Lexus dealership mentioned that they topped off my coolant after I brought the car in with this issue, but that the level was not low, and certainly not low enough to be the cause of the underlying overheating issue.

 

[NOVALX570]

Intermittent issues are hard to solve. Doesn't sound like it's an issue isolated to a certain driving condition? Seems like low speed around town/apartment, and also highway travel at speed? Is it triggering after under high loads or high rpm?

When's the last time you serviced the cooling system, including changing the water pump and thermostat? At 232,1xx miles, is it due? Were OEM parts used?

I agree, it can be a thermostat sticking, impeller degrading and slipping, even failing ECT sensor? Even a leak like in the common valley plate could be a source of air pockets.

Correct - this has happened at highway speeds and crawling through the neighborhood.

I had my water pump change by a local Indy shop probably 10k miles ago. I’m not sure if they changed out the thermostat at the same time and I don’t know if OEM parts were used. FWIW, both shops pressurized the system and confirmed there were no leaks. What would cause the thermostat to stick?

 

[gaijin]

I did not have any work done to the cooling system before this issue arose. The Lexus dealership mentioned that they topped off my coolant after I brought the car in with this issue, but that the level was not low, and certainly not low enough to be the cause of the underlying overheating issue.

So... the dealer topped off your coolant, but it wasn't low. Sounds like dealer double speak.

Is your coolant level still full? Note that the level in the coolant reservoir should be at "F" when the engine is cold. If it is below that, then your coolant is low. If you bring it up to F (using only Toyota SLLC (Super Long Life Coolant) which is pre-diluted) and then check later and it is below F, then you are either losing coolant or still blowing air pockets out of your coolant system.

No matter what the dealer may have said or done, what do you see now for your coolant levels in both the coolant reservoir and in the radiator after your truck has sat overnight and is "cold?"

HTH

 

[NOVALX570]

So... the dealer topped off your coolant, but it wasn't low. Sounds like dealer double speak.

Is your coolant level still full? Note that the level in the coolant reservoir should be at "F" when the engine is cold. If it is below that, then your coolant is low. If you bring it up to F (using only Toyota SLLC (Super Long Life Coolant) which is pre-diluted) and then check later and it is below F, then you are either losing coolant or still blowing air pockets out of your coolant system.

No matter what the dealer may have said or done, what do you see now for your coolant levels in both the coolant reservoir and in the radiator after your truck has sat overnight and is "cold?"

HTH

Thank you for this detailed response - I will check first thing tomorrow morning as I had to rush out today. Will report back tomorrow morning.

 

[NOVALX570]

Thank you for this detailed response - I will check first thing tomorrow morning as I had to rush out today. Will report back tomorrow morning.

@gaijin: Update - I just ran a quick 15-minute errand and parked my car in my apartment’s parking garage upon return. I left the car idling in park for about 3-4 minutes as I was wrapping up a call to a friend and the car started to overheat again. I turned the car off and checked the reservoir and it appears to be empty (see attached picture). Do you think this points to a leak both shops missed? I would think given the issue is intermittent that it is not a leak, but I’m clearly at a loss and quite frankly out of my depth…

 

[bloc]

Search for valley plate leak. Hopefully the shops are familiar with this on your engine but it's possible they aren't.

Or, it getting hot hurt a head gasket and now it's consuming coolant when it may not have been before. When you start it after fully cooling down overnight, does it run rough at all for the first ~15-30 seconds? It's a little easier to identify this if you put the truck in drive or reverse and drag the brakes, sortof creeping along. It'll tend to jerk a bit.

 

[NOVALX570]

Search for valley plate leak. Hopefully the shops are familiar with this on your engine but it's possible they aren't.

Or, it getting hot hurt a head gasket and now it's consuming coolant when it may not have been before. When you start it after fully cooling down overnight, does it run rough at all for the first ~15-30 seconds? It's a little easier to identify this if you put the truck in drive or reverse and drag the brakes, sortof creeping along. It'll tend to jerk a bit.

It does not run rough at all in the morning. However, after doing some research on the valley plate leak issue, I did briefly hear a sloshing or rushing water sound from behind my dashboard when i was running my errand which aligns with a potential symptom of that type of leak.

I’m planning on checking the reservoir before I start the car tomorrow morning as an update to the group and then dropping the car off after at local Indy shop and asking them to check for a valley plate leak.

 

[NOVALX570]

@gaijin: Update - I just ran a quick 15-minute errand and parked my car in my apartment’s parking garage upon return. I left the car idling in park for about 3-4 minutes as I was wrapping up a call to a friend and the car started to overheat again. I turned the car off and checked the reservoir and it appears to be empty (see attached picture). Do you think this points to a leak both shops missed? I would think given the issue is intermittent that it is not a leak, but I’m clearly at a loss and quite frankly out of my depth…

View attachment 4183754

@gaijin - I checked the reservoir this morning and it was still empty. Drove the car a few minutes to local Indy shop I previously took the car to and mentioned the issue popped up again this weekend and to check for valley plate leak or sticky thermostat along with anything else they think may be causing this issue.

 

[gaijin]

@gaijin - I checked the reservoir this morning and it was still empty. Drove the car a few minutes to local Indy shop I previously took the car to and mentioned the issue popped up again this weekend and to check for valley plate leak or sticky thermostat along with anything else they think may be causing this issue.

No matter what the indy shop finds, if you drive away from there make sure your radiator and overflow reservoir are full with Toyota SLLC (Super Long Life Coolant). Driving with no coolant is not good for the engine.

Good luck - keep us posted.

HTH

 

[Artie]

@gaijin - I checked the reservoir this morning and it was still empty. Drove the car a few minutes to local Indy shop I previously took the car to and mentioned the issue popped up again this weekend and to check for valley plate leak or sticky thermostat along with anything else they think may be causing this issue.

Coolant is going somewhere if the dealer did actually top it off but I’m with @gaijin, the dealership is not talking clearly. I guess they can top it off but it didn’t need much to get to full… it was almost full? Idk, I wish we knew what the level was at the start.

Regardless, I hope this issue isn’t terminal.

 

[CanadianRockyCruiser]

You will want to diagnose the coolant system:
-refill coolant with the correct Toyota pink long life coolant
-test for leaks with a radiator pressure tester (or have a shop do it)... this will help you find a leak, and they can come from numerous spots on the system (valley plate, water pump, radiator, hoses, etc)
-combustion gas tester (to eliminate or confirm a head gasket leak)
-confirm that your radiator fan is operating correctly and not stopping

-fix the leak, or confirm there isn't one

 

[NOVALX570]

Reporting back findings: Just spoke with the Indy shop and they said they are still not able to find a leak, but agreed that coolant is going somewhere. He said the oil looks clean w/ no coolant in it. I mentioned that the reservoir was empty after i let the car go cold last time it overheated, which he said was helpful and would follow up with tech and report back. I asked him about sticky thermostat or valley plate leak and he responded thinking neither of those are issues. Will report back as i hear more.

 

[Artie]

I’d be borescoping cylinders looking for clean piston heads.