Hi everyone:

i have been having the weekend from hell. the alternator burnt up. i changed it. then today the car started overheating. when the car is switched off there is a loud hissing noise from the rear of the engine(this is not a vacuum leak..it lasted for over 10 minutes and then i walked away and the noise was still there). i cannot see where the noise is coming from but i assume it's superheated water blowing out somewhere(into the valve cover perhaps?). the question is this, does anyone know where this noise could be coming from and if it might just be the head gasket and not a cracked head, et al? i can do a compression test (probably smart to do one) and i have not checked the oil to see if it's mixing with water. the car is on the side of the road and it was HOT. the engine has 210k miles on it. it has never been pulled. what does a head gasket cost, and *yikes* a head for these engines?

i doubt it could be a heater hose since i hear the noise under the valve colver, but i have never pulled a lexus engine so i dunno if there is something i am missing.

i do not think it is the water pump since water is going into the engine and when the car is driven fast the temp drops to nearly normal. all the fans are working.

is it cheaper for me to purchase a new car rather than to fix this one?

any ideas?
any help would be appreciated.

thanks,
Kevin

 

one test you can do is pressure test the coolant system.

 

could be the TB heater line spraying coolant on a hot part of the engine.
you able to jack it up and look around that way?
check the plastic cover for anything nasty and the ground under the car.

drain your oil out and see if coolant has mixed in.

 

How does the car run? If it was a blown headgasket you would feel a huge loss of power and a locomotive like sound under acceleration. Is there anything leaking around the headgasket? Does this noise only come on when its hot or all the time. And is there any coolant loss, have you notice the level of the resevour? Does the exhaust have a sweet smell to it? or a greenish whiteish smoke color? Have you pulled a spark plug to see if you have coolant vaporization on the plug? You also mentioned that when the car is idling it heats up, but when your moving freeway speeds it cools down. That right there sounds like a water pump, have you checked the peep hole on top of the pump to see if it is leaking? If the fans are working constantly it could mean your water pump took a dump. I would start right there and see if its something as simple as a water pump. If its not, the next best thing would be to do a compression test like TLW recomended.

 

thanks for the help guys! i worked on it for a few days and i think it might be ok now. one thing that bothers me is that my plugs were black and full of what looks like carbon deposit(looked moist) and the third plug was wet. i have never seen plugs this bad in any engine, and i have worked on more than a few.

i used to have a mechanic (dealer or Lexus trained guys) work on the car and i will never make that mistake again. i did this because my wife drove the car everyday and i didnt trust myself to work on it. all the clips in the engine bay are broken and some of the parts i paid to change were not changed. anyhow, such is life.

thanks for the help everyone! i will let you guys know how long my good fortune lasts

Kevin

 

You may have a leaking injector or bad plug wires, and try some hotter plugs to burn off the carbon.