“It needs a head gasket.”
Maybe. But clean oil, pressure behavior, coolant condition, and leak path matter. A missing seal or external leak can mimic a much bigger failure.
GM Vehicle Diagnosis · Tampa Bay
Own a GM with a weird problem? Call before the big repair.
Chevy Trax, Buick Encore, Chevy Sonic, Cruze, Equinox, Terrain, Enclave and related GM vehicles can produce symptoms that look more expensive than they are. We come to you, diagnose first, and tell you whether the shop’s answer actually fits.
The specific problems
These symptoms need a real diagnosis, not a guess.
Turbo underboost
Underboost codes do not automatically mean “replace the turbo.” Hoses, solenoids, restrictions, PCV-related issues, and actual boost control need to be checked.
Catalyst efficiency
A catalytic converter quote can be expensive. Before replacing it, the upstream cause needs to make sense: fuel trim, misfires, PCV/oil issues, leaks, and sensor data.
Oil leaks, rough idle, smoke
On GM 1.4T vehicles, PCV-related failures can point the scanner in several directions. The diagnosis has to check the actual crankcase and intake behavior.
Touchscreen dead, radio works
When touch fails but audio still works, the problem may be the touchscreen layer rather than the whole radio unit.
Airbag / passenger sensor
Occupant Classification System faults affect passenger airbag behavior. This needs careful diagnosis because it is a safety system.
Vehicles we see often
Same family. Familiar patterns.
Trax1.4L turboOverheatP0299Cooling
Encore1.4L turboElectricalPCVMyLink
Sonic1.4L / 1.8LEngineClutchCooling
Cruze1.4L turboP0299PCVP0420
EquinoxEcotec familyCoolingElectricalDiagnosis
TerrainGM sibling platformEngineElectricalDiagnosis
EnclaveElectrical-heavyWiringA/COCS
MalibuGM platformCoolingMyLinkDiagnosis
What We ask first
The first three questions tell a lot.
Before the hood opens, the car’s history starts narrowing the diagnosis.
How long did you drive it overheating?
Short, long, once, repeatedly — this changes the risk level.
Has this happened before?
Repeated symptoms point differently than a sudden failure.
Does it start, turn over, and have coolant in it?
These basics tell us whether the car is safe to test and what to check first.
Case highlight
2016 Chevy Trax: shop said head gasket.
The cooling system couldn’t hold pressure, so every symptom pointed to a major internal failure. The actual cause was a missing surge tank O-ring — a part that costs a few dollars. The car runs fine. No head gasket needed.
“Don’t approve the expensive repair until the simple failure points have been ruled out.”
Oni Repair · Tampa Bay mobile mechanicGM owner?
Tell us the code and what the car is doing.
Year, model, engine, mileage, code, symptoms, and what the shop already said. We will tell you whether the diagnosis makes sense before parts get thrown at it.