Smoke billowed from the car's engine, with the couple unable to see a thing.
Police arrived within five minutes with other emergency crews soon joining them. Now the couple - Barry and Elsie Wharfe, who are in their eighties - have thanked North Wales Police for their much-needed help.
The couple were travelling on the A470 from Llandudno towards the A55 at 4pm on December 24 when their car started smoking, leaving them unable to see the road in front of them.
A passerby saw the smoke and called 999. In less than five minutes, the great-grandparents were relieved to see police arrive.
The couple has since been in touch to express their gratitude to those who helped them.
Mr Wharfe said: "A lot of smoke was coming out of the car so we couldn't see a thing, we thought the car was on fire. The police, fire service, ambulance and the breakdown recovery were all so kind to us."
The road was closed whilst recovery was arranged for the car.
Mr Wharfe said: "The police told us not to worry, and that they wouldn't leave us until we were home safely. I am so glad no one was injured with so many people trying to get home for Christmas.
"We received excellent care and attention from the ambulance workers who checked that we were OK, and the fire service checked our car before it was taken away by the recovery s...