This is a 2007 V50, under 100,000 miles (in the 90's) car runs fine, MPG is good, a lot of power, idles well. This is my wife's commute car.

For a while we have been getting a PO2187 code but I can't find a vac leak. So because the car seems fine I've been clearing the code and going on with my life. Recently after the code was thrown I also looked at pending codes and I had a 300 301 and 302. Ok that is odd because I never feel any misfire.

This past weekend I'm under the hood and see the coolant is down a bit. I filled to the correct level.

Today when my wife gets home from her 30 mile stop and go commute I go to check the coolant. I am surprised to see coolant laying about - it was on top of my new upper motor mount, looked like some was on top of the reservoir and there was some down below the air inlet hose that is (I think) for the turbo. I'm not up to speed on the Volvo so forgive me if I am wrong about that big fat hose.

When the motor is running or not running there is no pressure in the expansion tank. I would guess that there is never much pressure because the cap is a 21 PSI cap which doesn't seem like much pressure.

Temp gauge needle sits straight up, never passes mid point.

With codes 300/301/302 misfires and leaking coolant a quick guess would be a small leak in the head gasket. No water in oil, car runs fine makes me think no on that one but maybe?????

We have the V50 and an S60 both turbos and they are my first turbos so I am not sure what is what on the engine. I could have a water leak in the turbo system.

Any ideas?

"...the cap is a 21 PSI cap which doesn't seem like much pressure...."

I'll admit to being old school but 21 lbs seems a bit high. Best to use the correct Volvo label cap if that's not what is on there now. Maybe 21 psi is proper and I'm just out of it.

One thing you can do is clean everything up, let it all dry out, then run it and watch for leak(s). Might it be the radiator leaking and spraying back on the engine?

You can also pull all the spark plugs out, pressurize the coolant system for a while, peak into the cylinders and see if they're filling with water. Well, look for leaks ANYWHERE.

A compression test might not be a bad idea either, but if it's running OK you're liable to find the compression to be OK.

I think 21 psi is correct.

I looked at FCP for OEM
https://www.fcpeuro.com/products/volvo-engine-coolant-recovery-tank-cap-30680002

I looked at IPD
http://www.ipdusa.com/products/7660/114349-expansion-tank-cap-p1-p3

Now the question -- is the cap in good working order?

The cap wiggles a bit when I push on side to side. It is suspect. The one on the S60 had male threads on the cap, it screws into the expansion tank and I can make it very snug.

The V50 cap is a female end and screws down onto the expansion tank neck. It has a stop point, almost like it is built into the cap. It just stops. You can't feel that there is not any torque being applied as it screws onto the expansion tank. It is the oddest thing I've ever seen but then maybe that is how it is to be?

Pulling the bottom engin cover to have a look below.

Inspect the cap and the filler neck for cracks or bad gasket. It should not wiggle. The pressure only exists when the coolant is hot. The temp gauge in the dash just means that the the rest of the coolant system is working properly.

Clean up the antifreeze with water, you don't want to leave that sticky stuff around.

You will want to flush the system before it gets cold.
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Keeping it running is better than buying new