I've been chasing wet carpets for the past few weeks. Thanks to the FAQ I eventually solved the problem. I saved hours of work and could have saved much more if I'd bothered to check there first. Something I preach, but obviously rarely follow. You can step through the story below and compare my attack to what you might have done. Or just skip to the final paragraphs for the conclusion. This was in one of our 900's, but the same story applies to 700's so I'm posting in that larger forum.

I was out of town when I got a panicky call from my wife. It's been windy, cool and wet here for weeks, a picturesque time of year when leaves, needles, maple seed wings let go of their footings. One surely depends on the heater and defroster. Finally a dryish day, she got around to cleaning her car only to notice both passenger side carpets under the floor mats were wet, as in soaked -who knows for how long. Front carpet was soaked along the right side, especially toward the front. Rear carpet was evenly soaked. I hesitantly asked about the water being mopped up -she said it was clear. I asked her to check around the floor air ducts -she said maybe a little moisture at the base of the rear duct where it touches the carpet. The car had recently had the windshield replaced (actually twice as the first one stress fractured) -she presumed it was a window leak. The car had been mildly rear ended last year; air bags and seat belt tensioners let go, but no body damage, although the driver door skin fit didn't seem as perfectly flush as it was before, so maybe the passenger doors were a bit out of alignment -again no, the doors were perfectly flush. Until I could get at it, I said to drive with the heater on full blast with recirculation and air conditioning on to help dry out the carpets. Also, crack the window open and tape over the air intake duct -in part because recirculate wouldn't totally cut off the moist outside air. I asked after she'd taped if the cowl intake screen was still in place -nope, totally dropped down. Based on her assumption, she also taped around the right side of the windshield. With everything sealed up, the problem seemed to subside. Good news, but not for long.

So, based on those symptoms, what would you guess? Where would you start? No scrolling down for the rest of the story until your theories are in order.

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For a wet front carpet there are numerous possibilities, but from the rear carpet symptoms it seemed most likely to involve the heater ducting. Looking under the dash there was a trace of water around the fan flange. Yes!! I've been down this path before -had it all figured out.

Last time I had such a problem it turned out to be debris clogging the cowl side drain areas due to the cowl screen dropping away from the mastic, as was definitely the case on this car. I removed the cowl, flushed with the garden hose and picked the drains clean. Hmmm, only got out a few leaves and needles, but both drains certainly ran better.

Next check was the long plastic cover over the air intake horn under the cowl. Yep, last guy to replace the windshield had managed to pull it away from the mastic seal. But in my opinion it would take a fair rush of water off the windshield or a lot of splashed water into the cowl intake to make it into the horn and down into the fan and ducting. A strip of new butyl mastic had the cover all sealed up -I put a curse on the windshield installer. Everything was put back and the garden hose was used for a thorough test. Hey, no more leaks from the fan! I patted myself on the back for a job well done.

While I was at it, I blasted water around the door seal. Oops, water coming in around the front lower corner of the sill. Hmm, two water leaks? The door skins are properly aligned so no need to touch hinges or latch strike plates. Oh well, out comes the block and mallet, a bit of hammering, extra caulk and the sill lip was now properly sealed. I did the classic test by closing the door on strips of paper and pulling them out to ensure an even seal. Enough already. Out with the carpets and foam, on with hydrogen peroxide to kill the mold spots, on come the heat lamps and fans. Definitely my expertise prevailed, out comes a well-deserved brew. After a few days everything is dry. Car goes back on the road. Happiness returns to my wife.

Two days later, wife arrives home from work a bit p.o'd. Bad news -wet spot on front corner of carpet. Car goes back off the road. Hmm, drops of water around the fan seal again. I start to repeat the process, taking the cowl off, but everything is nice and dry. Time for some fresh thinking. It's got to be in the air intake system. I start by dropping out the fan -water pours out of the fan motor when it's tipped on its side (sure hope the fan isn't going to rust, but after removing the shell and drying it out it will be fine). Reaching up into the main duct from the fan it was very dry, but maybe a trace of moisture along the back edge. Out came the Haynes/Chilton's heater housing diagram (you'll also find this in the FAQ). Looks like water could get in through the firewall around the heater core nipples, maybe a couple of other spots, but how could it flow over to the fan when there's that big dropped cavity for the A/C condenser? The rubber seal around the heater hose nipples looked fine. The next step working back toward the leak would be removing the lower cover under the A/C condenser -a job I've done before and it's not nice. By now some of you will have it figured. I was still mulling a few possibilities, especially that newly installed windshield.

I wasn't looking forward to removing the duct cover under the A/C condenser, especially if it turned out to be for no good reason. Time to sign on to the Brickboard and check the 700/900 FAQ -never know what you might find. Yes sir, there it was, along with what I'd already checked, the A/C condenser drain was mentioned in the top three category and I was just about to work my way back into that cavity by removing the duct cover under the A/C condenser and it would would have that drain. A quick feel up through the fan opening into the heater duct quickly confirmed the intake side of the A/C condenser cavity was wet all along the lower edge, but then the condenser is also sealed all along this edge.

Now this is where I was barking up the right tree in the wrong direction. Totally by luck, not by brains, I'd earlier flipped past a TSB for 700's about Volvo adding a drain tube to the A/C condenser outlet in the engine compartment to improve drainage -I hadn't quite related that to a total blockage. Now this car was built long after that 740 TSB came into effect, yet I didn't see any drain tube in this 940. Although it wasn't shown in the diagrams, it was now clear that the firewall drain grommet was directly on the back of the A/C condenser box, not at the end of some long tube. Whoa, is that a drip of water I now see sitting at the tip of that drain grommet on the firewall? I poked into the hole and immediately out comes a long stream of water -the entire contents of the A/C condenser lower heater cavity. Eureka!!! And to think I was about to spend hours so I could clean this drain from the other side. I didn't know whether to feel lucky or stupid.

I hope most of you didn't find this tale too long. For those who were way ahead of me on this, I either bow to your knowledge or pity you've been down this road ahead of me. For those of you who have never been near a wet carpet under the shade of this tree, maybe it's time for a bit of preventive maintenance:
o Find the A/C drain grommet in the firewall, poke it clear, suction it out. If you're chasing a wet carpet problem like I was, then rather than methodically following the water leak back to its source, start with a quick and easy check like this. Excess moisture in the A/C condenser cavity will also lead to mold and associated odors which can be difficult to eliminate.
o Check the cowl intake screen. If it's detached from the mastic then remove the cowl and properly imbed the screen into the mastic (see the FAQ).
o Flush water down into the cowl air intake. Aim down each side. Water should drain freely out the large slits under the rocker panels. Poke up with a screwdriver or a blast of air. Pick out any debris with a little hooked piece of wire. Make sure all other drains slits along the rocker panel and the doors panels are open. That's a major part of routine rust prevention.
o Periodically check under those floor mats during wet weather.

End of lesson.
--
Dave -own 940's, prev 740/240/140/120's & quasi-expert only on a good day