Still hunting my coolant leak. Not a big leak and I thought it was fixed with a new Volvo OEM cap.

In mid September I installed a new in the bag Volvo cap and went on vacation. Drove about 500 miles and some of it was in stop and go traffic.

Arrived home and the coolant level was right on the mark.

Today I was under the hood and saw that the coolant level is down to min. What? I have a great nose for smelling coolant but never smell any that is leaking in the engine. Although the blue may not have the same smell. I can walk by a car and smell a coolant leak.

So I was just out in the dark with a flashlight hoping to spot something out of the ordinary. I did see a small bit of liquid on the firewall side at the top lip of the reservoir.

Now I am wondering about the reservoir. One thing I have noticed is that there is never any pressure build up. I can remove the cap anytime without worry of coolant flying out. So I am starting to think that the reservoir has a leak and never allows the system to pressurize.

No overheating of the car, car runs great, etc.

Do the reservoirs on these cars have a history of going bad? If so is there a way to test?

Looking at my maintenance sheet I do see that the first I noticed a coolant problem was two months after a shop installed the top motor mount. Could they have nicked something?