All,

It started overheating, took to shop they replaced radiator with brand new, then replaced spark plugs, ignition coil, still over heating.. no smoke coming out, don't see antifreeze in oil. Shop telling me that it's my head gasket. Can that be? I see no signs of gasket issues. Any thoughts?

Much appreciated..

 

Engine type?

 

Think 2.4 or 2.5 not sure. They replaced thermostat too. Someone else said the heat sensor, but I constantly have to add antifreeze, no leaks or smoke but antifreeze is disappearing..

 

Engine cold, reach behind then engine block to feel below the intake manifold area, These area has a foam type heat insulation to protect the plastic manifold. Check if the foam is wet from coolant.

The head bolt threads machined in engine block can fail. The result being the head bolts are no longer holding the head to the block and a failed head gasket/coolant leakage.

Its a common issue. Search internet on "2AZFE head bolt thread failure" for more details and the fix.

A "block test" can tests for exhaust gases in the coolant (see internet for details). Exhaust gas in the coolant can cause overheating. The coolant system can also be pressurized with a hand pump to check for leaks.

Suggest if possible to stop driving the car. The constant overheating could damage the head or destroy the engine. Also start checking for coolant in the engine oil.

 

toyomoho is correct. The head bolts have failed on the back side of head. $1000 fix at a local garage which was about a grand cheaper then local dealership

 

If you can get that done for $1000,that is a real bargain,IF they use a Huhn kit and do all 10 bolts. If they use heli coils it probably won't last long. Time sert works well too. Most mechanics have to charge around $4000 for that job.

 

Good point. Correction, it was more like $1400. It was my sisters car. And I don't know if the kit was used. Looking at it now...sounds like heli coil may have been the fix. 123k on motor and it's burning oil. quart every 1000k. Toyota really failed on these 2.4l!

 

I've just been through the same scenario. The mechanic was all ready to put the head gasket in and started to put new bolts in and the thread began pulling out. I'm really bummed as it was my Dad's car and he recently died. The mechanic is wary about trying the rethreading because of chance of tearing the water jacket as the wall is thin. I called another shop in town who specializes in Toyota and he said he would suggest a new engine (not a used because of the oil leak problem). The car is not worth putting that much into it. It got 246000 miles and 17 years. Still hate that it is going down because of a design flaw.

 

Yes, it is a shame with these engines. Be nice if you could find a used engine that Toyota replaced the pistons with the new design ones

 

Replacing the block threads with inserts is now a common fix. Toyota even issued a service bulletin on how to do this.

http://australiancar.reviews/_pdfs/T...SB-0015-11.pdf