Coolant level dropping

I've noticed my coolant level dropping, so I got a bottle of the VW stuff and mixed it and added more.

My oil does not appear to have any foamy white goo in it. I haven't noticed any puddles on the floor but I should look more closely to be sure.

Suggestions what to look for?

I have been reading heater core threads, ugh. One more damn thing. The heating of the interior does seem a bit anemic now that I think of it. My car has 43k miles.

how close are you to me? I have a lift and a warm shop to make finding leaks much more pleasant- I dumped my coolant just in time, after 2 coolant changes my vents are almost to hot

If you have any hint of a coolant smell in the interior, then I'd highly suspect the core. The lines coming from the engine compartment will also be suspect. Two flanged aluminum lines each sealed by an O-ring and clamps just toward the firewall from the core.

Otherwise you have the intercooler and the EGR cooler and radiator. Water pump could also be an issue. A pressure test may be your only real option to locating the culprit. Before you do that I'd suggest using your nose in the engine bay. The aroma of drying coolant is fairly easy to detect. Hopefully just a hose with a bad section or a failed clamp.

As to anemic heat? I hadn't noticed the gradual drop in efficiency until I installed a new core last week. The difference is night and day.

How fast is the coolant dropping? Was it a one time thing, or does it continue to drop? The rubber hoses can expand over time, dropping the level below the min. line. The system also isn't 100% sealed. If you had to add much more than a quart, then I'd say you probably have a leak somewhere.

Mine was dropping slowly. Ended up being water pump. Been waiting almost two weeks for the water pump to arrive at the dealer. Car is 2015, has 35k miles.

The rubber hoses can expand over time, dropping the level below the min

Click to expand...

It might be just this, or some bubbles in the circuit that finally worked out. I just checked again after a trip and I don't think there was any more drop. I haven't had to add any where near a quart.

My sense of smell is pretty much gone by now, so I won't be smelling coolant in any case. Maybe I should ask my wife...

I guess in my next service I will ask for a coolant flush and replacement. Hope that is enough. Does everybody experience heater core blockage, or is it just a minority as most problems turn out to be?

Thanks for the offer jrm. I am in Hillsboro. I'll keep my eye on the level and see how it goes.

As far as coolant... Contaminated (worn out) fluid will become orange in color. Mine showed no trace of flakes, rust, or anything else. The inside of hoses also showed a slight orange tinge. Overflow canister was clean.

Will your core fail? I can't answer. We have two '13 Passats and neither appear to have a problem. My '14 was the culprit. Orange tinted coolant and a blocked core. I'm of the opinion that a flush wouldn't have done any good... And won't. At least as far as saving the old core.

You didn't ask about cause and I can only share that I don't have a handle on it. If a chemical reaction within the core I'd expect metallic oxides. As far as I can tell these were absent. Truthfully I'd be more suspect of the water used to mix with coolant at the factory caused this problem. (Just my suspicion.) One thing I can share is that backflushing the core is of very little help if any.

If there be a bright side to this, I've become intimate with my Passat. Not in all that good a way but I still like the car and would replace it with another if possible.