Water On Passenger Floor
Q: Whenever I run the A/C in my 2004 Chevy TrailBlazer a pool of water collects on the floor at the front passenger seat. I assume a line is clogged somewhere. Is there an easy fix or should I have a professional look at this?
A: Give it a shot first. Condensation is formed on--and drips off--the air-conditioning system's evaporator (cooling component within the dash) and collects in the bottom of the evaporator/heater core case. The water is then routed through the firewall, into the engine compartment, and down to the street through a rubber drain tube. When this drain gets plugged up with debris, the water level will rise and eventually overflow onto the passenger-side floor. Carefully jack up and support the right front of the vehicle, crawl underneath and look for the evaporator drain tube pointing downward at the street. It's usually made of rubber, removable, and pulls off easily. But don't forget to duck. If the tube itself is obstructed and holding back the water, it's going to be a gusher. If you're lucky, and that's all there was to it, you can clear the tube of debris, reinstall it, and be on your way. But there may be more debris inside the evaporator case still plugging up the drain path, and that's going to require compressed air to blow it out. Worst-case scenario is that the drain path is clear, and condensation is entering the passenger compartment through a cracked evaporator case, or a bad seal against the firewall. Second-to-worst, there's so much debris collected in the case that it continually plugs up the drain over short periods of time. This requires removal of the evaporator case for a thorough cleaning. Either way, it's always a good idea to carefully inspect the plastic screening at the cowl, right at the bottom of the windshield beneath the wipers. This is where outside air enters the A/C system, and any missing, damaged, or misaligned protective screens will allow leaves and other debris to enter the evaporator case, consequently stopping up the evaporator drain.
Too Much Overheating
Q: I have a 2001 Dodge Durango with 92,000 miles on it. This summer, it started overheating during a road trip. It's usually okay when I'm driving on a straight road, but the minute I hook a trailer to it or start pulling hills, it overheats! No mechanics have been able to diagnose the reason. I've had the following work performed on it and it still overheats: new heater core, new thermostat (even tried running without one), new water pump, new antifreeze, new radiator cap, and cooling-system power flush. I can drive it about 60 miles max, then the temp gauge rises so much I have to stop and all the water boils out all over the place. There's no water in the oil and no steam is coming out of the tailpipe, so I'm told it's not a head gasket. The fan clutch seems to be fine.
A: There are a bunch of things to check and double-check. Let's start from the front. Be sure there's nothing obstructing airflow through the radiator. Grille ornamentation, a plastic bag pinned to the front of the A/C condenser, a missing air deflector beneath the bumper, or leaf and debris buildup between the radiator and the A/C condenser, can all cut down on the essential airflow through the radiator. Also, you had the coolant-system power flushed, but what did that really accomplish? Even the best job won't clear a severely obstructed radiator. So you should bring the radiator to a fully equipped radiator shop where it can test the radiator's flow rate in gallons per minute. This will determine if the radiator still has the capacity to cool your engine. If 92,000 miles was the first time you checked your antifreeze, there could even be "grunge" partially obstructing the coolant passages within the engine block. High ambient temperatures and load on the powertrain (towing and climbing hills) maxes out a coolant system's capacity. That's why manufacturers offer towing packages with higher-capacity radiators and auxiliary transmission coolers. Is your Durango equipped? No water in the oil and no notable steam out the tailpipe isn't an all-clear on a leaking head gasket. Checking for hydrocarbons inside the coolant system's expansion tank with an exhaust gas analyzer is a more accurate test.
How To Reach Alex
If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 6420 Wilshire Blvd., Los Angeles, CA 90048, or e-mail us at trucktrend@sourceinterlink.com. Please include the VIN with your question. Due to the volume of questions received every month, we cannot guarantee that everyone's question will be personally answered or will appear in the magazine.