Audi Q5 Thermostat & Coolant Leak Repair in La Mesa

Audi Q5 black car parked outside of our shop | Euro Auto Tech & Smog

When the owner of this 2019 Audi Q5 came to us in La Mesa, that dreaded check engine light had been staring them down for weeks. They’d noticed some coolant pooling under the car, but like most of us, hoped it wasn’t serious. Unfortunately, the leak had worsened—and the dashboard warning wasn’t going anywhere.


At Euro Auto Tech & Smog, we started with a full diagnostic scan to uncover the real issue. The engine code pointed straight to a coolant bypass valve problem, so we walked the customer through our repair plan:


  • Identify and fix the leak — we replaced the failing thermostat housing and coupling that had seen better days.
  • Refresh and protect the system — a complete coolant flush ensured no contamination was left behind.
  • Seal it up and reset — with a new gasket and fresh coolant, we cleared the codes and confirmed everything was running perfectly.


In just two days, the Audi was back on the road, smooth, quiet, and leak-free—no warning lights, no overheating worries, and no more puddles under the car. The customer left smiling, confident that their engine was finally running like it should.


If they’d waited much longer, that small leak could’ve led to major overheating or costly engine damage.


Now, this Audi Q5 is back to doing what it does best—delivering a comfortable, reliable drive every day.


Ready to say goodbye to your own check engine light?

Bring your car to Euro Auto Tech & Smog and let us get you back on the road with confidence.

Best Practices for Fleets | 2023 Mercedes-Benz Sprinter
June 23, 2026
At Euro Auto Tech & Smog, we work with fleet managers and Mercedes enthusiasts who understand that maintenance isn’t an expense, it’s an investment in reliability.
Common Leaks | 2012 Audi A6 Quattro Premium - Euro Auto Tech & Smog
June 19, 2026
A properly repaired Audi should drive smooth, stay leak-free, and perform exactly the way German engineering intended.
Preventative Maintenance | 2015 BMW M3 - Euro Auto Tech & Smog
June 10, 2026
If you want your M3 running strong past 100k miles, preventative maintenance is everything.
Show More