I've changed all hoses, even valley hoses, therm housing thermostat, expansion tank, all hoses with it, new clamps every hose change, new manifold seals, we did pressure test over night, no leaks, but the smell is still occurring.
You can smell that smell after driving and parked, and when I stop at a light, if the recycle air isn't on in cabin, it pulls smell in through vents. No smell when driving or recycle button is on.
It's the last main issue with the car, except a small power steering leak.
I'll take any suggestion no matter how obscure.
Is there ANYwhere it could be leaking not visible with pressure test.
My mechanic is befuddled and has no other ideas.
We haven't changed the rad or the pump but no issues with those as we see it.

 

The heater core is always a possibility, particularly as vehicles get some age on them....

 

Phil, I would check for CO2 in the coolant. In my car, we did not get coolant in the oil, or oil in the coolant, but there was CO2 in the coolant. Did not show in a pressure test either.. It was one of the head gaskets.

I also finally replaced my expansion tank. Even after replacing the head gaskets, I still smelled coolant, and after replacing the expansion tank the smell finally stopped. The best part was that the tank was always dry on the outside, but we noticed some dry residue on the bottom, which was the final clue.

If you can't find a leak, and you still smell it, it is going somewhere..

I have a power steering leak as well. The part is in the mail, so I hope to fix that next weekend.

Best of luck!

 

I would have pointed you to the expansion tank as well, but see you have changed that already. I assume that included a new cap.

In my case, I had the same issue soon after changing out my expansion tank and top radiator hose. After a few weeks of searching and gnashing of teeth I finally found a pin hole leak coming from one of the radiator side tanks. (There is a plastic tank attached to both sides of the radiator fins.) I only found this after the leak got bad enough to start leaving some grayish residue. Up to then, the coolant loss was not even measurable.

I was able to use a hot water tank sealant product to close the leak temporarily, which also verified it was indeed the source of the problem when the smell stopped.

I ended up changing the radiator and was glad I did. There were multiple places on both sides that had started to crack, just had not yet started to leak.

Did the job myself, so only out the cost of a radiator and a few new hoses. Not difficult to change, just time consuming. Bought an aftermarket radiator which runs ~$300 plus a brass fitting to attach the trans cooler lines.

 

Coupling two of my life experiences I would make these observations:

A crack in the head of a VW put so much pressure on the cooling system that it blew hoses off.

A tiny crack in the Jaguar reservoir did not show itself until I kept pumping the pressure test equipment past 20psi. At that point it sprayed as a very fine mist that instantly dissipated with no drips or stains.

How high have you pressurized the cooling system?

A CO2 test sounds like a great next step.

 

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