I wish to share a my unfortunate experience at an automatic car wash two summers ago. Like most individuals, I left my engine running while going through an automatic car wash. On this hot summer day, I also left my AC running while passing through the wash. As my vehicle entered the massive soap waterfall section, I noticed my coolant temperature gauge quickly rising into the overheating region. My AC then started blowing out hot air. I then heard what sounded like my AC refrigerant spewing out refrigerant from under the engine compartment. My AC never worked properly afterwards until I later had it recharged.
What I had gathered is that the massive waterfall soap had gotten ingested into the AC condenser and radiator long enough for the engine to become overheated. The AC condenser blockage must have overheated the AC refrigerant system, causing excessive refrigerant gas pressure within the AC system. An AC over pressure relief valve must have released some of my refrigerant to prevent catastrophic AC system damage. Since this incident, no matter how hot it is outside, I now turn off my engine as my vehicle passes through the "soap waterfall section" and prevent ingesting that soap into my two heat exchangers. I hope this will avoid any engine overheating that may potentially cause my head gasket to blow or another refrigerant release.
I admire your persist sharing of your wise automotive knowledge and hope that you may share my unfortunate experience to your listening audience to expose people to this potential engine killer. I'm sure this has happened to many other owner's vehicles who hadn't yet made the above cause and effect connection.
--Roy T.
I then heard what sounded like my AC refrigerant spewing out refrigerant from under the engine compartment. My AC never worked properly afterwards until I later had it recharged
The condenser is in front of your radiator, which is at the front of your car. Unless you drove your car into the car wash with the hood open, it's not relevant.
What I had gathered is that the massive waterfall soap had gotten ingested into the AC condenser and radiator long enough for the engine to become overheated. The AC condenser blockage must have overheated the AC refrigerant system, causing excessive refrigerant gas pressure within the AC system.
AC a more or less sealed system that works at least 220 PSI on the high side, on the low side, it's still approximately at 50 PSI, falling soap can't get into a system that has more than atmospheric pressure (14.7 PSI at sea level).
An AC over pressure relief valve must have released some of my refrigerant to prevent catastrophic AC system damage.
I'm pretty sure there is no such valve. It's illegal to dump refrigerant into the air under Federal law.
Since this incident, no matter how hot it is outside, I now turn off my engine as my vehicle passes through the "soap waterfall section" and prevent ingesting that soap into my two heat exchangers
There's a cowl that prevents anything from getting into the HVAC system. It's basically a U-shape, precisely so you don't have outside things hit you in the face.
Compressors do have an over-pressure safety release valve. If it's a choice between blowing a hose and releasing all the refrigerant into the atmosphere or just releasing a small amount to prevent that from happening, the latter is preferable. (Realistically over time it's all going to wind up in the atmosphere anyway due to accidents, leaks, and equipment failure.)
As you point out the rest of the sequence of events is pretty much fantasy.
I didn't know that. I always thought since it came pre-charged from the factory, only a techie would be able to properly recharge it. Thanks for that.
Well thanks for sharing. I'll pass it on and one of my videos
