got one more explanation about o-rings at the sleeves and possible reason of their damage.
It could be overheating. Not a big overheating, that comes before cracks in the head, but small regular overheating every time your start the cold engine.
Place:
The reason for this could be a faulty(or just old) O-ring at the L-shape metal coolant pipe, going from the block of the engine to the head. At the block side its flange is bolted by 2 bolts m10 size, and at the other side its just pressed in the head. This L-shape pipe is located under the aircon pump holder, about 100 mm long, about 15-18 mm in dia
Reason:
Due to temperature changes head and metal pipe are expanding and compressing the o-ring. After cooling down the rubber o-ring returns to initial shape. By the time rubber becomes like a plastic and water starts leaking out(sometimes invisible from outside) and the air starts coming in, creating an air bubble in the gallery of the head, around injectors and sleeves. When the engine is started it takes some time to fill up the gallery with coolant and all this time injectors are working heated from combustion chamber.
Diagnostics:
At the beginning stage
Place the inner car heater temperature handle to max hot. Switch off the fan and radio. Start the engine and listen to the sounds near glovebox area. If you hear smth like water murmuring that means the air bubble was there. Repeat the test next morning.
At the escalated stage:
Park a car with a warmed-up engine at an angle to the front. Front side should be lower than a back, in my case 150mm of difference was enough.
Stop the motor and wait for 2-10 min, you will see a coolant drops under the car coming out pretty fast.
(--or just do a pressure test ---)
How-to-fix:
Take out aircon pump, aircon pump holder, belt tensioner. Unbolt L-shape pipe and pull it out. Replace the O-ring.
App time about 3h cleaning everything under aircon pump included.
Thats what I did yesterday after I got a spot of coolant under the car.
a bit of measurements:
old o-ring dimensions. Inner D =20mm, Outer D~25, H=3.5mm
I've tried to fit a replacement o-ring (from Bunnings) with Inner D=19 and Outer D=26 it was very hard and i decided not to force it in.
A little bit smaller from the same plumbing o-ring kit ($2.50 for a lot of them :-) ) fits well. But few weeks later it will be replaced with a genuine one, of course. Or a vitton one, if I'll find an equal replacement and it will pass my tests
WBR
Sergey
