Took my car in for service (tune up, transmission fluid change, new timing belt, new water pump) right before I left on vacation to do some work. On returning a week later, I noticed the garage had put about 40 miles on the car, which they justified as test driving long enough to let the engine heat up/cool down/heat up again.
So, is that reasonable? Or should I look for another garage?
What does cooling down have to do with how many miles were on it?
I don’t think it takes 20 miles for an engine to reach temperature. Not in CA in August.
The oil and the entire engine mass take longer than the coolant. I don’t know how much longer but that does seem a long ways.
The Central Valley has had much milder mornings than normal for this time of year.
I’m sure Rick or Gary T will be along to elaborate.
If your car had engine work done such that the emissions system was reset, then there is a specific cycle of warm up / cool down and driving certain times/distances at certain speeds that is necessary for the emissions system to recalibrate. I don’t know if the work you had done would necessitate that, but if the cycle doesn’t complete, you wouldn’t pass vehicle inspection because the emissions system wouldn’t produce the necessary readings, it would just spit out a big N/A.
I had some work done on my car coincidentally the week before I needed to get it inspected. The guys told me to “drive it around a few days” before taking it in. I did my usual driving plus put 100 extra miles on the car and still failed. I had to take it back to the shop twice before they had someone there who knew how to look up exactly what drive cycle my car needed. You see, they are different for every car! Yay! Then THEY drove it around for an hour to get it to cycle through, and THEN I passed inspection on the third try.
I don’t know if it calls for finding another garage, but I really am curious as to why they drove it 40 miles. The explanation given strikes me as horsecrap – an engine can be taken to fully hot, fully cold, and fully hot again sitting still. I do a wide variety of repairs, and hardly ever test drive for even ten miles. For the great majority, two or three miles is plenty (my area doesn’t have emissions inspections that require completing drive cycles).
I’d be inclined to pin them down on the explanation. The heat up/cool down/heat up thing, in and of itself, makes no sense. And as I’d venture that 99% of repair shops don’t find such long drives necessary, I’d be quite skeptical of any explanation. But I’m curious enough to at least hear what they say.