razzuh

Hi,

My 08 ES 350 started overheating on the first coldest day of winter in Michigan. I bought this car a month and a half ago and never faced any issue. It has 120k miles and one morning while I was going to work, the heating wasn't working as there was only cold air coming in. I started driving to let the air circulate in the system and when I was on the freeway, the car started overheating. I pulled over right away and diagnosed to see the radiator with no coolant (possibly a leak). Got it diagnosed at Midas and a radiator replacement was suggested. Towed the car to my local mechanic and he replaced the radiator. However, the heating still didn't start working and he says that one hose gets extremely hot while the other doesn't show normal operation. He even says he changed the thermostat in order to fix the issue and now the heating started working and the car doesn't overheat as he left it on for 2 hours. He isn't someone who does water pump replacement so he is advising me to take to another mechanic who would do it for me. He says its very strange and shouldn't be happening. I am worried as the head gasket is probably not harmed since I pulled over as soon as the needle started moving towards the red and there is no white smoke from the exhaust. He even replaced the serpentine belt as it seemed worn out resulting in inefficient pump operation but still the circulation has not been restored perfectly. Any help would be greatly appreciated as to what might be the issue and if the replacement of water pump would fix it? Also, he says I can drive it currently (not safe) but there isn't 100% circulation of the coolant from the radiator to the engine and back. Please help.

Thanks.

ESh

I bet the head gasket is unharmed since you stopped the car on time.

Do you have any info if somebody replaced the water pump before?
Those water pumps from 04/06 to 03/09 were trouble, they were ready to leak even after 10000 miles but the impeler was trouble free since it is made of metal.

Bad recirculation means bad impeler. Impeler can go wrong if it is made of plastic. That means somebody replaced the watee pump before, but then I know that no company makes the water pump for that engine with plastic impeler.

Now, the recirculation.
How he found out that there is not enough recirculation through the engine?

yeskay

if you read other posts it is a known issue in these models with faulty water pump,

razzuh

Thanks for the reply. He says one of the two hoses gets extremely hot while the other one doesn't. The hoses between the radiator and the engine. One that goes from the radiator to the engine and the other that comes from the engine to the radiator.

razzuh

Thanks for the reply. I see. The mechanic also says a sealant was used previously to fix a minor leak in the radiator that might have clogged the water pump.

jagtoes

When you ran out of coolant did you find the source of the leak. Did they perform a coolant system leak test. Did they bleed the coolant system after the installation of the radiator and thermostat. Did they verify that the weep hole in the water pump was not leaking. So far I'm not convinced that the mechanics that you are taking the car to know what they are doing. Have either a Toyota or Lexus dealer give you a diagnosis or someone who specifically services these type of vehicles.

razzuh

Even I am thinking they didn't bleed it properly and there might be air lock still as the left side vents blow mild hot air while the right side ones are cold. He said he found a leak in the old radiator. I guess you are right, I should take it to the dealer. Thanks.

Htony

First thing to do is pressure check and putting dye in the radiator to detect exhaust fume. Does the rad. blower come on when temp. rises? Water pump is a possibility too as well as radiator cap. If pump is weak you can feel the rad hoses one should be cool vs. the other should be pretty warm meaning water is circulating. Did you ever do cooling system flush? This sort of problem is best dealt with specialty shop.

razzuh

Yes, the blower comes on at high temperature and the car itself does not over heat now. I drove it last night. Regarding the flush, the heater wasn't proper when I bought it so I took it to the seller's mechanic and he did a heater core flush after which the heater was back to excellent. But then yesterday, a friend of mine who is studying automobile engineering told me that it isn't advisable to do a heater core flush for cars over 100k miles as this also leads to radiator failure. Don't know how true that is.

ESh

Did you check the coolant level?

razzuh

There was some coolant in the overflow tank but not in the radiator. Also, it was pointed to me that the previous owner used something other than the red coolant.

ESh

Did you check it after the repair?

razzuh

Yes. The level is all good now. I also started the car leaving the radiator cap open and the coolant level doesn't drop. Some of it starts to pour out so I guess it really is the water pump that's not doing it's job.

chuyrobles

If the mechanic said the coolant was not circulating after he replaced the thermostat and radiator, that leaves the water pump. I can think of only the thermostat and water pump affecting circulation like this. The water pump has a broken impeller or the impeller blades have corroded down to where the fins are not 'grabbing' the water. It's also possible the thermostat was installed incorrectly or it's faulty.

oldgrump

The coolant level rising in the rad is from expansion as the engine (and coolant) heats up, and is normal. I don't think the cooling system is full if you only have a small amount of coolant in the expansion tank. Install the rad cap and warm up the engine until the temp gauge gets into the mid-range. Shut the engine down, let the coolant cool down and then check the coolant level in the expansion tank. If the level is not between the F and L marks add coolant mix to bring it up to the correct level.