What the customer told us
Owner said the temperature gauge climbed anytime she sat at a light on Highway 40, and there was a sweet smell with white smoke on cold mornings. She had already had the thermostat replaced somewhere else and it did not fix anything.
What we found
Cooling system pressure test held, so the leak was internal. A block test on the coolant turned the fluid yellow, which means combustion gases are getting into the cooling system. Compression on cylinder 3 was down about 22 percent from the other three. That combination points at a failed head gasket, not a thermostat.
What we did
Pulled the head, sent it out to be checked for warp and resurfaced, replaced the head gasket set, head bolts, timing chain guides while we were in there, thermostat, and flushed the cooling system. Torqued to spec in sequence, refilled and vacuum-bled the system.
How it came out
Compression even across all four cylinders. Ran it up to temperature three separate times with the fan cycling normally, then road tested about eight miles including stop-and-go. No smoke, no coolant loss on a follow-up check a week later.
Parts fitted
- Head gasket set
- Head bolts
- Timing chain guides
- Thermostat and housing
- Coolant
Photos to add: Coolant block test turning yellow; Head removed, gasket failure between cylinders 3 and 4; Deck surface cleaned and checked for warp; Back together and running at temperature.
