[Scoobey]

Hi, helpful folks. My 2009 C70 (124,000 mi.) has been running a little rough for the past week, then the other night we had the following sequence of events:

- No heat from heater. (My brain: ok, need a new heater valve, nbd.) Then:
- Oil light comes on. (A grocery store's right there, so I pull in, buy a quart, put it in.) Oil light goes off.
- A couple miles later, oil light and then check engine light come on. I pull oil cap; visible vapor comes out (very hot oil?), but temp gauge shows dead center.
- Half mile more to destination, park car, Lyft home, have it towed the next day.

Mechanic just called, said it was completely out of coolant and that an air bubble around the thermostat might be responsible for there being no indication of high temp. Said it's probably a cracked head gasket that allowed coolant into the cylinders until it was all gone, and that replacing the gasket, machining the current head, replacing valves, etc. will be $3,500-$4k (and a few hundred more if a new used head is needed). Codes he pulled included ECM3100, 3110, 3120 (specific cylinder misfires), ECM3410, 341c, 341d, and 2B00 (bad thermostat sensor -- ???), and 304c (knock sensor).

Questions:
- Does my mechanic's explanation sound right? Do head gaskets just fail like that in the absence of some other problem? I'm more used to high temp CAUSING a cracked head etc.
- Would you recommend replacing the gasket etc., or would it be better to find a low-mileage used engine, or even a remanufactured engine?
- In short, what's your advice for restoring this car to reliable condition without breaking the bank, and making sure it doesn't happen again?

Thanks!!

 

[RR04]

What engine you got?


Sent from my iPhone using Tapatalk

 

[Monocog007]

It sounds like you're leaving out a lot of useful information... Why not make sure the car is topped off with oil and coolant before trying to diagnose your issue?

1) These cars are known to have leaking coolant reservoirs. So maybe the RESERVOIR was empty but not the engine.

2) If the oil light came on, that's bad news bears for the bottom end of the engine. Either the oil pump isn't building pressure or you ran it so low that the oil pump was starved. Did you not check the dipstick? What was the oil level before or after adding an entire quart?

I'd be very careful about conflating these 3 issues you're having, otherwise you're in for spending a lot of $$$ without much resolution. Sounds like you need to find a mechanic better at diagnosing issues with facts and not theories, I think you're being taken for a ride.

 

[paradoxicallymodified]

A compression test or even better a leak down of the cylinders would yield more info than blah, blah, blah from a mechanic as far as the gasket. Oil vapor from the fill tube is normal when hot, especially if your a bit low. As far as the coolant goes, this is why it is required to do the coolant under vacuum so the “air bubble” cannot happen. Same for the A/C system. I would have the coolant done properly, an oil change, and a compression/leak down test done before buying an entirely new/used motor or a head gasket replacement. If your mechanic doesn’t want/or cannot perform these I would look for a new mechanic.


Sent from my iPad using Tapatalk Pro