Annoyed

I was driving home tonight with the sunroof open. When I accelerate I still seem to get an intermittent mildew smell with the HP AC unit off. I poured an enzyme-based cleaner down the Cowell twice and cleaned it with hot water. Is there a next step?

Make sure your carpet isn't wet anywhere. Feel the carpet in the rear and under the seats. If the carpet is getting wet, it will stink after awhile.

Will do, the smell is not constant. I randomly get a puff that seems to be coming from the HVAC but I will check the carpet.

If the Evaporator drain tube is plugged or partially clogged then you will get condensate water and/or some of the solution you poured into the intake cowling to run down the passenger side of the cabin, out of the HVAC plenum, and under the carpet.

Pull that part of the carpet back first to see if the insulation under the carpet is wet. Then you'll know.

You may still have to pull the HVAC plenum down to clear the drain or try using some low pressure air into the rubber drain tube from under the car up into the plenum to try and clear any obstructions.
It all depends what you find.
Glad to hear you have no freon leaks anymore. That's good news.

That sounds promising. Where does the drain tube come out underneath the car?

carguy8888 wrote:

That sounds promising. Where does the drain tube come out underneath the car?

If I remember correctly it's somewhere under the passenger side below where the A/C plenum is in the car.

A long time ago I remember someone on here posting a pic of the rubber nipple coming down from the body.

Wish I had a pic for you, but someone else may have one. Albert's always a good source for these kinds of things or try
"Search" and see where that gets you.

It can't hurt to blow some low pressure air up the tube. Don't hit it with a lot of air pressure (No Shop Pressure)
something regulated to much lower pressure so you don't blow that nipple off the bottom of the cabin.

That's what I will have done. Thank you.

Rickw wrote:

carguy8888 wrote:

That sounds promising. Where does the drain tube come out underneath the car?

If I remember correctly it's somewhere under the passenger side below where the A/C plenum is in the car.

A long time ago I remember someone on here posting a pic of the rubber nipple coming down from the body.

Wish I had a pic for you, but someone else may have one. Albert's always a good source for these kinds of things or try
"Search" and see where that gets you.

It can't hurt to blow some low pressure air up the tube. Don't hit it with a lot of air pressure (No Shop Pressure)
something regulated to much lower pressure so you don't blow that nipple off the bottom of the cabin.

I don't have that picture.

Also, however, if the nipple is *missing* then for some reason the condensate will run into the cabin.  I have never figured out why that is.  My guess is yours is missing.  

Read this thread for explanation and pictures.

A parts counter person who knows GM cars well enough may be able to find you one of these tubes, or a substitute that will work fine; similar ones were used on a number of GM cars. I have heard that you can fit a short piece of rubber tubing in place of the spout but I have no idea whether that will really work right.

Peace out

Albertj

https://rivperformance.editboard.com/t3783-where-is-the-a-c-drain-located?highlight=A+C+drain+tube

https://paulstravelpictures.com/GM-HVAC-Water-Leak-Condensate-Drain-Rubber-Elbow-Cleaning-Guide/index.html

https://www.google.com/search?client=firefox-b-1-d&q=Air+Conditioning+drain+on+1998+Buick+riviera

Oops.

The threads about this are https://rivperformance.editboard.com/t3783-where-is-the-a-c-drain-located [the problems here were dirt blocking the tube, and the wrong tube installed] and https://rivperformance.editboard.com/t12360-where-does-this-go [shows the drain port from looking-up-from-ground].  

The GM part number was 25723079.

One way to get one would be to take one off a 2005 or earlier Park Ave in a junkyard, using a razor or scraper, then gluing it onto your car's drain port using silicone or urethane.  

But first, just check if it's blocked.

Albertj

I will get it on a lift next week to check when I install my new rear suspension level arm. I did notice water coming out of the bottom of the car when I poured hot water down the cowl and I don't hear anything swishing when I make turns. Great advice as usual.

carguy8888 wrote:

I will get it on a lift next week to check when I install my new rear suspension level arm. I did notice water coming out of the bottom of the car when I poured hot water down the cowl and I don't hear anything swishing when I make turns. Great advice as usual.

If you open the hood and look at the firewall on the passenger side, below the A/C lines, you should find the duckbill or the hole.

As for the swishing... Had you heard swishing in turns prior?

Never heard swishing. I don't think anything is leaking onto the carpet, I have big rubber mats unless I am smelling a random drop of something. The odor is intermittent not constant.

carguy8888 wrote:

Never heard swishing. I don't think anything is leaking onto the carpet, I have big rubber mats unless I am smelling a random drop of something. The odor is intermittent not constant.

The leak goes under the carpet onto/into the padding. You might want to check there.

Today it smelled like old rubber. Just waiting for some time to have time to have it looked at.