velani

Hi All,

I have searched and searched for YouTube videos or for documented instructions on replacing the radiator thermostat. Has anyone replaced one and who can share help, I would truly appreciate it. I cannot find a service/shop manual or procedure to replace the thermostat.
I have been getting error P108 which is causing the Check Engine light to be on, preventing a successful DOT inspection.

I cannot even figure out where the thermostat is, on the top hose to the radiator or the mid hose. To the left of the engine or the right side. Thank you in advance for any help

HomerJay

Search the forums if you need more info.
https://www.clublexus.com/forums/es-...hermostat.html

Oro

velani

So sorry for my typo. The code is P0128

Oro

velani

That could be a good possibility. What/how would you isolate the sensor as opposed to the thermostat being the issue?
In my case, it is taking too long to get to a higher temperature so I was assuming that the thermostat was not closing all the way. To test it, should I start the cold engine with radiator cap off to see if the coolant is moving around freely? This would tell me if the radiator is closed but the sensor is faulty?

Oro

If it is taking a long time to get to temp (indicated via the dash gauge moving slowly), that's a classic sign of a stuck-open thermostat. IF the gauge is moving, then your temp. sensor is likely just fine. If you have suspicion, you can test it by removing it and checking with a multi-meter, or use an IR thermometer at the upper rad. hose to see how quickly it changes and what it stabilizes at.

For make-up coolant, use only the red p-hoat coolant as original. You can get it everywhere nowadays, Zerex Asian as mix or Pentofrost A1 as concentrate if you prefer. CarQuest has the OE coolant (concentrate) at a fair price, too. You do not want to mix the red with old style green, yelllow/AMAM, or DexCool (orange).

velani

Thanks and repped Oro. I am finally rolling up my sleeves today. It is most likely the thermostat. I used a probe temperature gauge with an open radiator cap and the temperature started to creep up almost immediately. I then repeated the test on my Camry and found that the temp did not move up for over 2 mins indicating to me that I have an open stuck thermostat. Going to replace the thermostat now. Will report back, thank you.

Oro

velani

Thanks a bunch Oro, that is exactly what I ended up doing. I bought T-stat at Advance Auto which was so light in weight in comparison to what came out of the ES300. Since the dealership had closed yesterday, I picked up an OEM T-stat for $24 this morning, OEM Gasket and connecting pipe O ring from Toyota. Well worth the price and a peace of mind. Just finished with the entire job and I am so happy that I took the time to replace it myself. Very happy.

Everything works, the engine heated quick enough on the first start, the needle on temp gauge went a notch higher than I have ever seen. On the first drive and on full heat, it was pumping out some heat so I am excited that it will serve us well in the winter. I am so thrilled to have completed this job on my own. It took far too long but I know it was done right.

Your tip on using Pentofrost A1 saved me at-least the cost of OEM T-stat. For that, I sincerely thank you and repped. You have been a true help which I truly appreciate it. How many miles do you have on your 02 ES300? I have 160k.

Next project is to change the shocks and struts. It is driving loosy goosy and I am fairly sure it is time. Do you or anyone else have recommendation on the best that I can buy for a fair price?

I has searched far and wide and could not find a video that covered T-stat replacement and Temp sensor on a Toyota V6 (same engine on the ES300). Now that I have, wanted to share if for the next person looking for it: