Overheated and lost compression in 7 cylinders (1 Viewer)

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Sep 11, 2019
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Newport News virginia
Ok so I was driving my 05 lx470 and it started to overheat before I noticed it I felt powerless then the car cut off. After towing it home and not being able to start it after a day I did a compression check and only one cylinder has compression. 7 cylinders are dead. I’ve never seen a car drop 7 cylinders off a blown head gasket. Is it possible it jumped timing and the motor is unable to seal in a compression test? Any help would be appreciated skilled techs where would you start?
 
Ok so I was driving my 05 lx470 and it started to overheat before I noticed it I felt powerless then the car cut off. After towing it home and not being able to start it after a day I did a compression check and only one cylinder has compression. 7 cylinders are dead. I’ve never seen a car drop 7 cylinders off a blown head gasket. Is it possible it jumped timing and the motor is unable to seal in a compression test? Any help would be appreciated skilled techs where would you start?
I'd start by checking the timing... When was the last time the timing belt/tensioner/etc was all changed?
 
I might do a leak down test before checking timing since I assume checking timing would mean tearing the engine mostly apart. Maybe scope the cylinders but I assume you won’t see anything the leak down test would tell you.

Since the engine was driven until it shutdown I wouldn’t put it out of the realm of possibility that it’s really fubar. Would be interesting to see the heads if you end up tearing it apart.
 
Does the engine still spin? Through the starter, or by hand? If it does not spin through the starter, but does by hand, that could point in the direction of broken timing belt. Best bet as mentioned above are compression and leak down tests, and scoping while you’re in there. These plugs are very easy to get to and you should know pretty quickly after running these tests.
 
I didn’t notice the temp gauge till it was hot quickly through on the heat and it came down to normal 2 min later power loss and car cut off while driving 60mph I took the passenger timing cover off and this is where the timing marks land

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That’s the crank at 0 looks a little off to me

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Have you found out why it overheated? Assuming a bad coolant leak. Broken heater Tees? Did the temp gauge give you any warnings?
Radiator was leaking temp gauge went up then I turned on the heat to clear some of the heat went down to normal then shut off and temp gauge skyrocketed

I didn’t notice the temp gauge till it was hot quickly through on the heat and it came down to normal 2 min later power loss and car cut off while driving 60mph I took the passenger timing cover off and this is where the timing marks land

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This is with the cam lined up perfectly the crank reads 5 degrees off
 
Radiator was leaking temp gauge went up then I turned on the heat to clear some of the heat went down to normal then shut off and temp gauge skyrocketed

Just "leaking"? How bad and/or for how long? Seems like the system would have to run pretty low on coolant pretty fast to escalate to this amount of damage. Did the radiator top explode? Did one of the radiator hoses pop off?
 
timing marks look fine, must of got really hot unfortunately, you can take the valve covers off and watch the valves, may find something there but prob need to rebuild/replace the motor if your confident in your compression test, you can do a leak down also to double check.
 
Get a borescope and inspect the cylinder walls, I bought a 100 that overheated and six out of eight was scored near zero compression.
I was able to locate a clean engine out of a Seqouia from Car-Part.com with documented mileage and VIN.
 
If the engine cut out, then you might have damaged the engine. I once overheated my toyota 4afe engine and to cool off I open the heater core valve.. which melted most of soldering on heater core. So take it as a warning to not to use the heater core to cool the engine off during an overheated incident.
 
It had a leak where I would add coolant every two weeks for the past two months

Which seems a bit strange if you were aware and on top of this radiator leak and you never let the system run very low why would it all of a sudden overheat that bad. I wonder if something else in your coolant system blew you are not aware of.
 

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