Gents, The cold start shaking was happening once a year... During the maintenance of 215.000km, Toyota service could not find any issue. Now it started happen 60-70% of times. Took it to a garage next door, but the problem could not be reproduced. They checked spark plugs etc which were slightly loose. They also refilled the coolant - because it was lower than low level. There was no error logs in the computer. I just came back, tried next morning and again bang on. it was shaking like a crazy ant drunk significant part of the coolant. Can we say for sure that these two symptoms shows head gasket issue? Or it can be EGR + some leakage issue in cooling system? Btw Engine has almost 230.000 km on the clock. Would it be good idea to swap with an second hand engine with low milage. I also uploaded a cold start up with shacking engine.
You know the answer and it's been too long for a gasket only repair. As always, diagnose properly but start with the end in mind. Block egr and borescope tests. Starts at egr block flow test At about 10:15 in the video he starts talking about the egr valve letting "air" into the intake manifold. He means exhaust gasses. Car Care Nut HG Borescope at 660s
Sorry, thats almost 100% head gasket. Try this. Remove the oring on the coolant over flow tank. This will eliminate the pressure in the coolant system . That pressure pushes coolant past the leaking HG into the cylinders. Might buy you a little time BUT it sound like your HG leak is bad enough that damage to cylinder walls, Piston assembly. Coolant is not compressible so the piston gouges walls or worse connecting rod bends.
EGR system ever cleaned? Assuming not, it'll be clogged with carbon, including the intake manifold's EGR passage, which lead to excessive and uneven heat in the engine, which lead to head gasket failure, specifically coolant leaking into combustion chambers, with the largest accumulation when the car's been driven, then sat overnight. While EGR cleaning is always good, it's conflation to think it'll "reverse" the head gasket leak at this juncture. (Deja vu: my second such post this morning)
If they said this cleaning would "cure" a head gasket failure already started, say around 150k miles, they're delusional. If they said to a full EGR cleaning every 50k miles, from the outset, I'd concur.
