Peligroso

Hello guys,

I am looking for some advice on my lexus overheating. I've done some research, but there are tons of answers and nothing matching my issue. If that is OK, I would like to start a new thread and get some fresh answers, instead of answers from way in the past.

Car:
1992 Lexus ES 300, Automatic

History:
My daughter was drive the car to school and said it over heater, someone at school gave her coolant and drove it home.
I have done the following and I can't seem to get anywhere:

- Filled the radiator, let it sit on idle and it eventually overheated and water came out from the reservoir tank.
- Replaced thermostat = same issue
- Replaced both radiator caps, one of them was pretty bad = same issue
- The car will sit on idle with A/C on and it will idle smoothly and temp is where it needs to be. I accelerate the car and it stays working perfectly, the car idles like a new car.
- I took the car out for a spin around the neighborhood, as soon as I stepped on the gas, the needle started going up to 3/4 of the way.
- I also feel like stepping on the gas the car is not a peppy as it used to be, like no power at all
- I parked the car in the garage and water was boiling again and coming out of the reservoir tank
- There is no smoke coming out of the car
- The oil does not have anything that suggests there is water or condensation in the engine
- I checked the cooling fan, it is my first time seeing a hydraulic motor that works with PS pump. I put my finger on the fan when it was idling and it stopped, it was not too hard to stop it... is this normal?
- I have someone coming over in 2-3 days to check with a tester if in fact it has a blown head gasket.

anything else I should check or if some of you have had the same experience?

Thank you in advance!

ES300NZ

when was the water pump (and cambelt), last replaced, the pump might be toast.

Is there oil in the water ?
is the header tank water getting super hot ? (cracked head/headgasket)

It's possible combustion and water are mixing, causing it to super heat.

CUMan

If it is overheating while idling, the first thing I would check is the operation of the hydraulic cooling fan. It could be that the fan is not speeding up enough to produce adequate airflow through the radiator.

The speed of the cooling fan is controlled by a module under the glove box. This module monitors coolant temperature and sends a signal to the power steering pump when more cooling is needed. The PS pump then increases PS fluid flow to the hydraulic fan, and the fan speed goes up.

The operation of the fan can be checked by connecting two terminals (paper clip, perhaps) in a small terminal box that is located just to the right of the passenger side strut mount. The box is about 1' by 3". The top flips up revealing numerous connection points. Shorting these two terminals will cause an increase in the fan speed if everything about the fan control is operating properly. I don't recall which of these two terminals need to be connected, but this particular test has been discussed numerous times on this forum. Do a search for "hydraulic cooling fan operation" or something similar. The Haynes manual for the Camrys of these years discusses this test and tells one which terminals to connect.

If you connect the terminals, and the fan doesn't speed up, the next thing to check is the wiring harness coming from the firewall to the PS pump. If this harness get disconnected, the fan speed will not step up when more cooling is needed. There have been numerous postings involving this particular issue. The harness is not easy to see from above the engine. Better access is possible by removing the right front tire, and then removing the fender panel. The PS pump can then be seen. Look for a wiring connector plugged into the top of the pump. If it cannot be seen, look for it hanging down from the firewall.

mitmaks

Possible that coolant temperature sensor is not working properly. Also you don't want to use your fingers to stop running engine fan, unless you don't mind them being torn off. Check power steering fluid, is it full? Maybe there's air trapped inside the hose somewhere and fan is not running as it should. Any lines leaking? These cars are prone for leaking power steering lines.

Peligroso

Thanks for all the responses, much appreciated.

I don't think the issue is with a blown head gasket or water pump or anything related to that. The water pump was replaced within 10k miles and it is not leaking at all, I have checked the water pump and it seems to be flowing and it is not leaking.
None of the cooling hoses are leaking either, all the clamps are fresh, no cuts on hoses either.
My friend brought over a kit to test if there is fluid going into the engine, but the kit never revealed anything after 45 mins of the car in idle, neither when we accelerated.

I think the fan is the issue, it just doesn't seem to pull air at all, even when you step on the accelerator. I am seeing a little bit of power steering fluid leak somewhere, as I see it on the floor in the garage, but I have not been able to pinpoint the leak. At first we thought it was the hydraulic motor and a quick google on that motor turns out to be about $500, does that motor go out often? well, it is an old car, so it is probably time for it to go, but I can't seem to spend $500 on that motor.

A thought was to put in a 14 inch electric fan and always keep it running to cool the radiator, put the fan in front of the radiator, so make it a push fan, instead of a pull fan. Thoughts on that?

as mitmaks mentioned, I'll check the Temp Sensor by the thermostat, as it was very easy for the cable to come off and it just doesn't feel like it "clicks" when connecting the cable back in.

CUMan, I'll check on the module for cooling. Is this module under the glove box, right under it or does the glove box need to come off?
Looks like you have good info here, I'll follow those steps and check the forum for further information.

Thank you guys, you have given me plenty of information to go with.

LeX2K

The good news is the fan is not difficult to test at all.

Attachment 486220

Bwr1947

How did it work out for you? Did you get the electric fans?

LeX2K

Peligroso hasn't been on this forum since 2015. If you have a similar problem post in this thread or make a new one.