Quote:
Originally Posted by Piotrsko
Dumb question now you are involved in disassembly.... why not do a pressure differential test to see if a cylinder is actually leaking and where?
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Not a dumb question. A compression or leakdown test would be how you'd typically diagnose a blown head gasket and these days even shade tree mechanics often use borescopes.
When I got the car, the owner said that he took it to two different mechanics and they both diagnosed a blown head gasket. I talked to one of those mechanics personally and confirmed that was his diagnosis. He also said the engine was not overheating, just loosing coolant (which gives me a sliver of hope it won't be warped).
I have personally diagnosed the valve cover gaskets as bad as well as the valve stem seals. It also needs a new waterpump gasket. And there is a metal plate between the heads that seals coolant with form-in-place gasket that needs to be resealed. It is possible to do all that work with the heads still on, but much easier to do valve stem seals on the bench. And since the timing belt & valve covers will be off, pulling the head at that point is only a little more work.
There is still a small chance the head gaskets aren't blown. The waterpump and upper water plate leaks explain the coolant loss and the bad valve stem seals and valve cover gaskets might explain the rough cold start (oil seeps into the cylinder overnight around the valve stem seals and seeps on top of the spark plug by passing through the valve cover's coil seals). But at this point I think it is more likely that I'll discover the engine isn't worth fixing because I doubt an engine that leaked this much coolant never ran low & overheated.
Junkyard engines are cheap and plentiful here as long as you don't mind 150-250,000 miles. But I have a mental hangup about paying a shop $2,000 in labor to install a $500 engine that might not be much good. I certainly don't want to pay $7,000 for them to install a rebuilt engine ($5,000 engine, $2,000 labor) into a car that isn't worth $10,000 even in today's crazy market.
I didn't feel comfortable pulling the engine myself, but also knew I'd become more comfortable with that idea if I became more familiar with the hybrid system after pulling the heads. And that is the case. The hybrid system really isn't that bad - I think the book time to remove & replace the hybrid engine is 22 hours vs 20 hours for the non hybrid V6 highlander.