Here are the sequence of events that took place, do you have any suggestions?
1) My heat stopped working a few weeks ago.
2) I topped off my coolant the heat came back temporarily.
3) I looked for coolant leaks could not find any.
4) I did notice that when I start up the vehicle cold, their is a loud noise, like a rattle or maybe bad bearings, can't really describe the noise. But it is definitely coming from the thermostat or the water pump.
5) The heat would come back hot as normal along as I was on the accelerator hard, at idle the heat would go right back to being cold???
6) All this time over the past few weeks, the engine temp never over heated, the needle was right in the middle.
7) Then 2 days ago, the heat stopped working completely under all conditions, and within 5 minutes of the car being started the engine starts to get too hot and the needle moves about 2 ticks shy of the red mark
8) I went to Murrays, rented a Radiator Coolant Pressure/Temp tester
9) The test have left me confused. The test results seem to point to several or multi failures, which seems unlikely.
10a) Pressure test: An engine off test with system pressurized with the pump did not show any leaks in the system.
10b) Temp test: The temp gauge of the tester which was mounted in the over flow tank never moved above a few degrees farenheit even though the vehicle was overheating. This would lead me to believe the thermostat wasn't opening when the temp reached 180F, as spec'd in the Lexus Maintenance manual so the hot coolant never circulated throughout the system.
11) The Cooling Fan runs continuously as soon as the car starts and never shuts off, till the car is off. This makes me believe the ECT sensor is bad or the Fan Relay has failed.
12) During a warm engine, I increased the pressure in the system to 17PSI, and then I started to get Coolant leaking pretty good. Seemed to be coming from the Head gasket, but really couldn't verify that. I was able to verify the coolant was now leaking from the water pump, that I was certain of because I could see it.
So to summarize: It seams my water pump has failed.
It seams I could have a possible head gasket leak, but I cannot confirm, since I only saw steam coming from one side of the engine or exhaust manifold area.
A fan that never shuts off.
A thermostat that doesn't seem to be operating, unless the temp test result can be explained by a failed water pump?
My question finally is, could one failure of any of these components explain these symptoms? Do I have multiple failures? Could one failure that was neglected have caused some of the other failures?
I almost forgot to mention, I have 123,000 miles, my records show timing belt replaced at the dealer, 4 years ago at 98,000 miles. I called the dealer and asked them why they didn't replace the water pump, they said they don't change them because they don't fail. What kind of BS is that?