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I’m in the same boat did my oil change today and noticed the coolant. Cleaned it all off filled up the reservoir and noticed a small leak coming from the bottom of the upper radiator hose ordered a new hose and clap because the upper radiator looks good. Car has 66k miles 2015 but I do live in the Mojave desert
This is doable without removing the bumper, at least it is on a 2012. You just have to shove these air deflectors over some to expose the holes. Then use a really long extension and slip it through the front grill. I also replaced the fan bearing bracket as the bearing was pretty bad. https://www.rockauto.com/en/moreinfo...02574&pt=11548
Last edited by whizzer929; 08-30-21 at 02:07 PM.
Reason: crayons
Hey everyone! So I've got a weird overheating issue going on with my 2011 GX460, has about 193k miles on it. Basically it overheats, fairly quickly. I have heat, no smell or smoke from the exhaust. It appears as though the water is boiling off the top of the engine and out the overflow tank. I see active steam and hot water coming out of overflow tube to container. There is no coolant in the oil and no oil in the coolant.
Things I've done
No codes in Techstream.
Checked oil - Nice and clean no chocolate milk
Checked Coolant - No oil in the coolant
Thermostat - put in boiling water to verify it opens
Water Pump - This was replaced and I verified its working.
Coolant Leak test - 15lbs for 15 minutes, no leaks.
Compression check - ran this in TIS with 10 second no fuel crank, passed on all cylinders.
I've tried burping the system, jacking up the front end and running it. Tons of foam and bubbles which leads me to think head gasket, but yet it passed compression and leak test, so...?
For the life of me I can't figure this one out. I can feel the upper hose and it's hot AF, lower hose is nice and cool, almost like water isn't circulating. The vehicle actually overheated on my GF about 50 miles from home. I couldn't figure it out on the side of the road so I took the thermostat apart and drove it home with an open thermostat, didn't overheat or lose any coolant. Obviously that's not a solution, just a temporary fix but still makes it feel like the coolant isn't circulating and the thermostat is to blame, yet it's not.
Like I said, completely out of ideas at this point. I'm going to head to autozone and get one of those combustion gas test kits as a last resort as the foam throws me off. Hoping someone out there has some suggestion as this one has me stumped.
I agree with the combustion gas test. 15LBS for 15 minutes is much lower than combustion pressure, so it might only be leaking into the cooling system while the engine is running.
If that's not it, could the radiator be clogged?
So update to this, combustion gas test was negative, so head gasket is for sure out, it's passed a leak test, no water in oil, compression test and combustion gas test. I swapped the radiator cap with one from my other Lexus and there was no change there. I had someone suggest a leak in the heater core that's only showing up with water flow and is causing some sort of vapor lock.
Still out on what exactly this could be, but I'll update as I get closer to a solution.
Wonder if your replacement water pump is defective in any way and causing cavitation issues to account for the bubbles? How long ago was it replaced?
Was pink coolant used?
Radiator obstruction?
If you are parked, do you notice temperatures dropping under moderate throttle? Seems strange that your lower hose is cool - points to some sort of circulation issue.
When was the last time coolant was replaced? If it's been a while, at 193K might be worth changing the coolant out and making sure all air is purged out of the system. I've had air enter cooling systems before and cause havoc, though it seems you've done that. My next thought is a clogged radiator--when was the radiator last replaced or checked?
When was the last time coolant was replaced? If it's been a while, at 193K might be worth changing the coolant out and making sure all air is purged out of the system. I've had air enter cooling systems before and cause havoc, though it seems you've done that. My next thought is a clogged radiator--when was the radiator last replaced or checked?
curious on this matter, keep us updated. My gut is radiator blockage issue.
Here are the photos from radiator leak I experienced at 105K miles on my 2015 GX. This seems to be a common failure, so anyone who thinks they can slap a new hose clamp on this brittle plastic and be done is in for a nasty surprise. The leak developed and worsened rather quickly, so I recommend replacing the radiator at first signs of this. I was probably a few trips away from a catastrophic failure of the radiator, since I had to add more and more coolant after each short trip while waiting for the new radiator to arrive. The original water pump was also already seeping and had noticeable bearing noise at that mileage as well, so having the radiator out the way made replacing that a bit easier. Overall, I am not impressed with the quality or longevity of these parts.
UPDATE: The saga continues with another issue, a misfire (see my other post if you all think you can help), but hey, at least it doesn't overheat anymore, small wins? You're all gonna love this, it was a bad radiator, near as what the shop can tell, it has a hairline fracture in the radiator that only opened when the engine would get the water up to temp. I took it to a local buddy of mine who's a diesel mechanic and we shot it full of UV dye and let it overheat. The radiator was lit up like an xmas tree inside the fins but it wasn't dripping. We pulled the radiator and swapped it with a used one from a junkyard, overheating problem solved. I called a local radiator shop to see what it would cost to have the old radiator looked at as this problem really stumped me, I mentioned to him what was going on and he immediately said it was a hairline fracture in the aluminum inside the radiator. Said he's seen it a few times where they open with heat but close up enough to pass a pressure test. The crack allows coolant to escape into the fins and it immediately evaporates which creates a air pocket in the radiator keeping the coolant from circulating all the way through or going through fast enough. The rest is science, radiator doesn't cool fast enough, coolant in top of engine gets hot, boils out the overflow.
So there you have it guys, next time I'm gonna start with the UV dye, would've answered this faster.
Anyhow, home garage mechanic shop remains open since I've moved on to another vexing GX issue.
08-04-21, 08:58 PM
Strange Overheating Issue - Need some ideas
