I just had the water pump replaced. No signs of overheating. Doing about 75 on the interstate when steam that smells like anti-freeze starts coming into the car through the vents. The rug on the passenger's side was also wet.

However, my heater core is bypassed. Can someone explain?

 

I'd suspect the water pump job for the obvious leak, since it was just done. When was the heater core replaced? If it was also just done, may be some residual coolant leaked? Sorry, not a great answer but there is just no way that a bypassed core will leak--the only way coolant can enter the cabin is through the heater core. Now, you may have a water leak on the passenger side and water can get it after rain or a wash, etc. Is the carpet wet with coolant or water?

 

Heater core was never replaced. It stopped working so I bypassed it. Passenger's side rug is wet with coolant, but I thought the core was on the driver's side. That's what is so confusing.

I am wondering if a faulty thermostat could cause steam that smells like coolant to come into the cabin through the vents.

I don't see any coolant leaking from the new water pump. I checked where I bypassed the core and the clamps are tight and no kinks in the hoses.

I'm totally baffled!

 

perhaps residual coolant
also how was the core bypassed? are there still and hoses on the ports at all?


get some compressed air on one of the 2 ports and try to blast out anything that may still be in there to dry it out!

 

Sorry, I meant "bypassed", for the core...
If you have steam, and a coolant smell you have leak! Take it back to whoever did the pump and ask them. I don't like to take chances with the cooling system, it's the thing that kills Volvos!

The heater core is on the passenger side...

 

I bypassed it by removing the 2 heater core hoses and connecting them with a brass hose fitting and clamps. The connection is not leaking. The in and outlets for the core are on the firewall driver's side -- not passenger side. No hoses connected to them since the bypass.

I'm going to have the folks who installed the water pump check it out tomorrow.

 

if the heater core is bypassed in the engine compartment, then you're smelling steam sucked in via the cowl air ducts. next time you smell it, pull over, leave engine running and pop the hood and investigate, it should be pretty evident where its coming from.

 

You are correct as the inlet/outlet lines enter the firewall close to the driver side near the center. The lines run closer to the passenger footwell where most of the center console needs to be removed to get the evaporator out. So if there is no hoses connected to the 2 nipples then the source of the steam/smell must be coming into the vents but the wet (does it smell like coolant) is strange as there are no other sources for the water. My net is if you didn't have the smell before and have it now then go back to the guy who did the work. Also are you sure the guy didn't hook back up the evap.