Gavs98Z28

Hey guys,
Let me set up a quick timeline. this is regarding my mom's 2008 IS 250 AWD V6.

I took it to the dealer for a recall on Tuesday May 5th. When I picked up the car, their safety inspection showed that the water pump was leaking. Estimate was $835.

I ordered the pump and a serpentine belt from amazon ( brand of the pump was Aisin and the belt is Gates ).
My mechanic ( who once built race cars ) installed the pump on Friday May 8th. the car was driven Friday evening, Saturday morning and afternoon. I changed the oil on Saturday evening... no leaks.

My mom has a short drive to the train station. She noticed a puddle of fluid under the front of the car yesterday.
When she got home, I opened the hood to reveal coolant all over the front of the engine.

I took it back to my mechanic. He fixed a stud for the T-stat housing and replaced the "new" gasket for the outer water housing ( where the radiator cap goes ) with the one that came off the car.
the "new" gasket that came with the pump was destroyed.

filled the car with coolant, allowed it to run and no leaks. I drove it home ( about 10 minutes and 5-7 miles ), when I got home the front of the engine was still dry. i parked the car and shut it off....after about 25 minutes, my dad and I checked it again and coolant was leaking again.

is it just a drip after the system builds pressure ? is there another problem area where these vehicles leak from ?

all hoses are in good shape.

any help would be greatly appreciated.

thanks in advance

roadfrog

Is there any indication where the leak is coming from? Are all hoses properly tightened up? Did the mechanic "burp" the air from the system with the bleed screw? So many possibilities here. I changed out my own water pump on my LS460 and it was fairly straightforward. There is another possibility.....on the LS, there's a plasic outlet that the overflow tank hose attaches to. This is located on the drivers side top of the radiator. That outlet commonly gets broken when any work gets done on the engine by leaning on it or knocking it with an elbow or tool, etc. See if it's still in tact. Another area to check is the thermostat housing. Since the stud was "broken", I wonderif the fix was successful.

Gavs98Z28

We took the car back to the dealer that informed us of the leak.

Their diagnosis was that leaks were coming from the inlet water housing O ring and the waterpump gasket.

The SVC writer informed me that our mechanic used "fipage" which I'm assuming he meant an RTV ( or similar ) product on the outer edges.
Could the gasket have been bad from the aftermarket part ? Maybe.

The lexus tech removed everything, installed a new waterpump gasket and the 2 O rings that go with the install.

Put everything back together and so far so good.

The writer told me you only have to put a small amount of RTV on the bolts that hold the pump in place.

makes sense, just happy the car is fixed.

fastnoypi

sounds like the first tech pinched the o-ring during the first install.