Red overheat light has flashed and been on shortly when pushing the engine accelerating and during high speed (85-90) freeway driving. I noticed the the coolant reservoir has turned brownish at the inlet (top) and the coolant has been escaping through the safety cap, the cooling level going below "low" on the reservoir a couple of times. When leaving the engine on in maintenance mode, the fan turns on, the radiator and the hoses leading to the reservoir get warm to the touch. I'm thinking the radiator may not function properly. Different issue, but maybe related: The engine has about 240,000 miles on it and I replaced the head gasket 20,000 miles ago. Recently I have noticed that it started using a bit of oil. I cleaned the intake manifold and the EGR system thoroughly recently and I have an oil catch can installed, but it still throws the P0401 code regularly, and the gas mileage is in the mid 30'ies. Any advice much appreciated!
This happened to me. In my case it was the engine water pump. To clarify, the engine coolant in my reservoir was of normal color. It did not turn brownish when I had the issue of overheating. That’s another issue of it’s own.
At what miles did you do the EGR cleaning? Did you clean the intake manifold? Did you disassemble the EGR valve, clean/inspect it's interior? There's a plastic "ramp" at the bottom, critical to it's function, prone to distort/fail. Perhaps more so with protracted neglect, due to extra hot exhaust gas coming through, possibly due in turn to EGR cooler so carbon coated it doesn't cool properly.
I bought the car at 170K, cleaned the intake manifold and EGR system at around 200K and again at around 320K. First time I did disassemble the EGR valve, but I had trouble getting the screws out the second time, so I just checked it electrically per the workshop manual. Maybe I should go back and take it apart.
Ok, and replacement engine 240k miles back. Impressive! (In a year or two our 2010 may get to 100k, kilometres… )
Actually, the engine was replaced around 220K so it's been 170K on the "new" engine (70K on engine when installed, so yes, 240K on that engine). I did replace (did it myself) the head gasket on the new engine 20k ago and I could probably have done that to the original engine and it would have been fine, but I got a good deal on an installed replacement engine, water pump and catalytic converter and back then I did not have the mechanical skills or courage to replace the head gasket, I later developed, working on the car. I installed a new water pump yesterday, going to test it today, hopefully that takes care of the overheating problem. Hardest thing installing the pump was to torque the 5 bolts correctly in the tight space. I had to remove the passenger side front wheel and the side wheel well cover to the engine department to get to the lower bolts. There was a lot more "magnetic" resistance when turning the new water pump compared to the old one, so I'm pretty confident the pump was the culprit of the overheating issue.
I described above, I diagnosed the old pump to have different resistance to manual agitation than the new one. And I was right, no overheating during the 1200 miles I have driven since the change out. As a surprise benefit, the P0401 code has not shown up either.
I have similar issues with my Prius. I have a 2011. Changed out engine, water pump, sensor and thermostat. I have issue when I drive high speeds 70-80 mph up hill. Reservoir very hot almost to boiling temperature. Temp red light would turn on or flash and then when I slow down it will eventually turn off. My mechanic replaced literally everything minus the radiator and the inverter coolant pump. Can anyone please help???? No codes or no check engine lights just the red light engine temperature turns on when driving high speeds up hill for long periods of time. Is the issue temp sensor on EGR pipes? My mechanic has replaced with all OEM parts. Any advice? Toyota service rep says might be inverter water pump, radiator clogged up, or water pump. Just had Toyota dealership diagnosed and they check for any leaks so it’s not the engine. They said water pump and thermostat. My mechanic replaced those 2 parts. I thought I was in the clear but I wasn’t. The car still overheats when driving high speeds 75-80 mph for long periods of time and red temperature light turns on again uphill at high speeds. Anyone please help and TIA
Overheating its pretty much always one of the three things, no coolant, water pump not pumping, or thermastat valve stuck closed. I actually have my thermastat valve stuck open on my other car so i can never get heating, but at least my engine wont overheat. The brown in your coolant is the same problem im experiencing right now. Also getting mid 30s in gas mileage due to the misfiring from it. Im convinced oil is seeping in at the headgasket to mix with coolant. Have you replaced the headgasket yourself or did a shop do it for you? Im curious if this is something id want to tackle or if it isnt worth it considering my engine blocks could be warped.
