2008 c30 coolant loss

[Pretribrapper]

Ok. I'm lost.
Losing coolant. Not sure how.
Initially the coolant was leaking out the overflow tank. I replaces the cap and it seemed to fix rhe issue. Then, I noticed I was still losing coolant but no Idea where.
I did coolant pressure test and no issues.
I did exhaust gas test and no issue.
Mechanic said he thinks it is leaking out bottom of my actual reservoir tank but he said it was leaking from a spring in the reservoir. There is no spring in the reservoir and the cap was replaced so that new one is good.
Anyone know if it actually could still be the tank itself?

[MoVolvos]

.
Check the T / Y tube. There are two different ones depending on whether it's an auto or manual transmission. The plastic T or Y connection joint acts as a pressure clamp so when it cracks there will be a slow leak without obvious signs. It also bury in the middle of engine so you can't see the hose readily. Had I known the plastic was a clamp I would have carefully removed it and just use regular hose clamps and reinstalled. We opted for the silicon hose set which in hindsight was costly besides we didn't have time to change the others so it's sitting around.

Pelican has some useful DIY guides.
.
https://www.pelicanparts.com/techarticl ... o_Tech.htm
.
https://www.pelicanparts.com/catalog/Su ... atalog.htm
.
https://www.pelicanparts.com/More_Info/ ... 2&DID=6641
.
https://www.pelicanparts.com/More_Info/ ... 2&DID=6641
.

[Krons]

If it is the tank you should be able to see it.

I just sold a 2008 C70 and based on risk of catastrophic octopus hose failure and overheating/engine failure I changed all the hoses and thermostat plus the housing. Worth considering if planning to keep the car, not a bad DIY job.

If the octopus hose is leaking under the intake it’ll be hard to tell as it is buried under a lot of stuff.