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2014, 192k on the clock. I just noticed this today, its 94F out and I had the AC on...it actually went a little higher than this too. This was driving around, if I parked, it was in the middle or a little below (normally its a little below the middle). It got like this on the freeway and I wanted to see if turning on the heater would lower it, and it did. The radiator fans come on, coolant is at the full mark on the tank, no pink crusty stuff by water pump, i changed the oil last week and it's at the normal level so what the hell ? I've never seen it like this! any ideas? I had to re-register I forgot my info lol
drain and fill the coolant every 50k, never flushed, never changed the thermostat or water pump but I don't see any leaking by the pump? likely the thermostat?
drain and fill the coolant every 50k, never flushed, never changed the thermostat or water pump but I don't see any leaking by the pump? likely the thermostat?
Thermostat for sure...at the mileage you're at, water pump is a must...or you're asking for trouble later.
Thermostat for sure...at the mileage you're at, water pump is a must...or you're asking for trouble later.
Apparently that's what it was. A local shop wanted $282 to change it, I grabbed the $65 duralast one from autozone and after an hour and a half in a dark garage with a flashlight all appears right in the world again. Only took 3 feet of extensions to get the bottom bolt off under the thermostat from underneath
So after I popped the hood initially, the upper radiator hose was real hot but the lower one was just real warm, a sign the coolant wasn't circulating... not sure what a bad thermostat looks like but this is it. Drove it in a spirited fashion for 15 minutes after, didn't even get to halfway.
On a side note, that thermostat looks pretty clean compared to those I've changed.
Yeah the water pump is a good suggestion. It's not fun to wait until they go out to change. Maybe plan on that in the coming months, 200k miles is a successful life span.
If it was my car I would do the suggested water pump just to be safe. You might want to replace the radiator cap with a new OEM one also. Some Lexus radiator caps come apart and cause overheating. It happened to me on my 2006 GS300 and my friends 09 IS250. My friends car unfortunately was being driven by his daughter at the time who kept driving and ruined the engine.....over a stupid faulty radiator cap. When I picked up my 15 GS350 last year first thing I did was replace the radiator cap with a new OEM one. Its cheap and better to be safe than sorry.
On a side note, that thermostat looks pretty clean compared to those I've changed.
Yeah the water pump is a good suggestion. It's not fun to wait until they go out to change. Maybe plan on that in the coming months, 200k miles is a successful life span.
Probably an $800 job, wonder how hard that is? I mean I did the serpentine belt and thermostat
If it was my car I would do the suggested water pump just to be safe. You might want to replace the radiator cap with a new OEM one also. Some Lexus radiator caps come apart and cause overheating. It happened to me on my 2006 GS300 and my friends 09 IS250. My friends car unfortunately was being driven by his daughter at the time who kept driving and ruined the engine.....over a stupid faulty radiator cap. When I picked up my 15 GS350 last year first thing I did was replace the radiator cap with a new OEM one. Its cheap and better to be safe than sorry.
It's nice to see the forum pull together with suggestions and solutions...definitely what the forum is all about.
To the OP's observations about the temp gauge and radiator hoses it solidifies that the issue was indeed the thermostat...also confirmed by the fix after installing the new thermostat. If you put the faulty thermostat in a container of hot water you will likely see it open slightly, but no more. As the lower rad hose was only warm, the thermostat was opening at least a little.
In regards to the waterpump, if there are no signs of leakage from the breather hole (the pink crusties) and no noise, then I would consider it to be good. However, 200K Miles is a great service life and to replace it as preventative maintenance is arguably a good idea.
Although, it's not like the waterpump won't give you indications it's time for it to be replaced, i.e. the pink crusties, noise...through regulator vehicle inspection at maintenance intervals a failing waterpump should definitely be identified before it actually fails.
To the radiator cap comment, I definitely think the OEM radiator caps are great quality, and if I had a vehicle with an aftermarket cap, I would absolutely be installing an OEM one.
Over a lifetime of owning/driving Toyota/Lexus vehicles, going back to the 90's, I don't think I've ever had to replace a rad cap...or it was so long ago I can't even remember...definitely haven't changed a cap in the last decade at least, likely much longer than that.
Well damn. Something else is up. It's not as bad as it was, but I noticed that if I really get on it like flooring it to merge onto freeway etc the temp goes up to 2/3. Again, turning on the heat brings it back to normal. If I'm just cruising 80 on the freeway it stays a hair under half.
I'm thinking it's one of 3 things and would like your guy's feedback.
1. Water pump is just not efficient any more, failing somehow internally. There's no abnormal noise, no leaks.
2. The temperature sensor (whatever it is) is malfunctioning, seems unlikely.
3. The serpentine belt doesn't have enough tension, Under hard acceleration it's slipping and not spinning the water pump fast enough to circulate the coolant fast enough...
I changed the serpentine belt about 2 months ago, it was tight cause it was hard as hell to get on with just a small ratchet on the tensioner.
What do the top and bottom rad hoses feel like now? If they are equally hot at operating temperature then it's not the thermostat again.
Is the system bled completely of air since you changed the thermostat?
What's the level of coolant in the reservoir when the car is cold? It should be full.
1. Water pump is just not efficient any more, failing somehow internally. There's no abnormal noise, no leaks. Not a possibility given the symptoms you have.
2. The temperature sensor (whatever it is) is malfunctioning, seems unlikely. Yes...unlikely, considering it reads correctly the majority of the time.
3. The serpentine belt doesn't have enough tension, Under hard acceleration it's slipping and not spinning the water pump fast enough to circulate the coolant fast enough... It's an automatic tensioner, if the belt was slipping you'd hear noise from the belt.
What do the top and bottom rad hoses feel like now? If they are equally hot at operating temperature then it's not the thermostat again.
Is the system bled completely of air since you changed the thermostat?
What's the level of coolant in the reservoir when the car is cold? It should be full.
After I drove it last night both hoses were equally hot, that's why I figured hey that was it, it's fixed.
I had the front end up on ramps, drained from the petcock valve, after everything was done I filled it back up through the radiator then filled the overflow tank to the full line. I checked both today before I drove it and they were the same. This is really bizarre.
After I drove it last night both hoses were equally hot, that's why I figured hey that was it, it's fixed.
I had the front end up on ramps, drained from the petcock valve, after everything was done I filled it back up through the radiator then filled the overflow tank to the full line. I checked both today before I drove it and they were the same. This is really bizarre.
When you put the thermostat in was the jiggle valve in the correct position? If not is could cause air to be trapped.
WTF! Overheating IS350
