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Vintage 142 Water in the Trunk

142 guy

Member
Joined
May 31, 2014
Location
Saskatchewan, Canada
I did a fairly extensive resto on my 1971 142 which included replacing both wells in the trunk behind the rear wheels. The reproduction wells came with flat spots where the rubber drain grommets / plug things would be located; but, no hole for the plugs. Since those holes had previously required constant rust maintenance on the car, I decided not to cut them open. Since the trunk was getting a new gasket and the panels would be aligned and everything was going to be seam sealed the trunk should be dry, right?

Shortly after getting the car back together, I discovered that the trunk was accumulating quite a bit of water in both wells after heavy rains and car washes. Water does not appear to collect anywhere else. The tank area remains dry. Testing with a garden hose and checking showed that the biggest source of water was from around the drain box for the extractor vent under the rear windshield. During the resto work we had missed the fact that the seam sealer at both ends of the drain box (above where the drain hoses attach) had contracted and pulled away from the body allowing water to drain out the ends and into the trunk. It was a pain fix with the car upright (it would have been so easy on the rotisserie); but, I pried off the original seam sealer and completely resealed the box. Subsequent hose testing showed that the drain box exterior was dry and the water collection rate in the wells was significantly reduced; but, still eliminated.

Since sealing the drain box I have tried various things in search of a dry trunk. These include removing and carefully reseating the gasket in its channel in the trunk lid, sealing all the screws in the aluminum trim plate at the back of the trunk opening with butyl and adjusting the hinges and the strike plate so that the gasket is more tightly compressed when the lid is closed. All of this and after about 1/2" of rain last night I still had about 1/4" of water in the bottom of both wells.

I have checked and at this point there does not appear to be any water entering from the front side of the trunk lid / opening. As far as I can determine the water appears to be entering somewhere around the rear corners of the trunk opening, either above the tail lights or just to the outside of the tail lights. I have done a grease smear test on the gasket and there appears to be two spots where it looks like there is a lap weld between the rear 1/4 panels and the rear panel that the gasket does not contact solidly on either side of the car. This spot appears to sit a little lower than the rest of gasket contact area. I don't know that this is the source of the leak; but, I thought perhaps I could bump the sheet metal up a bit with a mallet so that it is level providing for a better gasket seal; but, no deal. Whether it is the lap weld or whatever, the sheet metal at that point is very rigid and any persuasion is likely to cause distortion in adjacent panels so modification of the contact area is a no go.

Right now I am at a bit of a loss as to where exactly the water in entering. Perhaps Volvo added the drain holes because they gave up on trying to seal the trunk lid. Have any 140 owners dealt with this and found a path to a dry trunk?
 
Your last statement I would think hit it on the nose.

Any time you deviate from the originally released as-engineered product, you have to wonder if you actually knew something that the volvo engineers didn't.

Sounds like you're just following in their footsteps, and will eventually wind up with the same conclusion they did... drain holes.

I think if you properly seal the drain hole grommet to your sheet metal with a sealant of your choice, you'll eliminate the water being drawn in between the sheet metal and grommet through capillary action, which is what causes the rust under the grommet. Sort of like when you apply a new sink flange, and use plumber's putty to ensure water does not go between the flange and basin
 
Also, I think the rear side marker lights would be a good area to inspect, assuming you still have them. The two screws seem to pull out the sheet metal on the quarter panel and allow a gap in the gasket. Then water drips right into your spare well
 
I can't remember the specifics on my 1979 242GT; but, the tail light arrangement is quite a bit different on the 142 / 144. The tail lights sit in a metal enclosure / bucket that appears to be seam sealed to the back trunk wall. I suppose that it is possible that the seam seal on the bucket has failed (just like it did on my air extractor drain box). I will have to have a look inside the light housings to see if there is any evidence of water. If the seam seal along the bottom of tail light has not failed then water would have to fill up to the level of the light socket before it could spill into the trunk and that definitely has not happened.
 
Your last statement I would think hit it on the nose.

Any time you deviate from the originally released as-engineered product, you have to wonder if you actually knew something that the volvo engineers didn't.

Sounds like you're just following in their footsteps, and will eventually wind up with the same conclusion they did... drain holes.

I think if you properly seal the drain hole grommet to your sheet metal with a sealant of your choice, you'll eliminate the water being drawn in between the sheet metal and grommet through capillary action, which is what causes the rust under the grommet. Sort of like when you apply a new sink flange, and use plumber's putty to ensure water does not go between the flange and basin

If water in the trunk wells is an inevitable, that would be a disappointment. One of the obvious problems with the drain plug in the wheel well on the right side is that the spare tire sits on it so it does not really drain. I like to store stuff in the left well; but, if water drains in there from above, even if it eventually drains out that stuff is going to get wet and end up smelling.
 
Also, I think the rear side marker lights would be a good area to inspect, assuming you still have them. The two screws seem to pull out the sheet metal on the quarter panel and allow a gap in the gasket. Then water drips right into your spare well

When I did my resto I filled the side marker lights to eliminate the holes in the panels that result in the inevitable rusting that starts around the side marker lights.
 
Volvo_1213755.JPG


The open part faces in. IOW the long leg of the seal that's hanging down faces out so that it curls towards the trunk opening when closed like so.

140TrunkSeal.jpg
.
 
The open part faces in. IOW the long leg of the seal that's hanging down faces out so that it curls towards the trunk opening when closed like so.

140TrunkSeal.jpg
.

Thanks for the picture (of a very crusty gasket). That is how I had it installed. Yesterday, out of curiosity I removed the gasket and installed it so that it curls out. This actually eliminated leakage on the right side and increased it on the left. Back to the 'correct' installation today. The gasket is definitely going to be well lubed with silicone grease when this is done.

I did more water experiments yesterday. With the trunk lid open I flooded water across the back windshield. The water drains down the glass and into the channel around the trunk opening and down the sides exiting over the tail lights. No water enters the trunk so the body (in that area) is water tight. If I close the trunk and repeat the flooding exercise water enters the trunk over the rear trunk sill just inside and above the tail lights. Right where that raised lip on the channel around the trunk opening ends. It appears that water is getting under the gasket somewhere towards the front edge of the trunk, likely around the front corners. The water then flows down the channel around the trunk opening between the inside of the gasket and that raised lip. When it reaches the back edge of the trunk the gasket prevents the water from exiting over the sill so it builds up and then flows into the trunk. I need to figure out why the gasket is not sealing along the front edge of the trunk.

As an absolute last resort I might just accept the fact that the gasket is not going to seal at the front edge of the trunk and cut out 1/4" sections of gasket roughly over the tail lights to let the water drain out.
 
It seems like you have plenty of places to look, having recently replaced a lot of things...
Even though it might not apply to your particular leak, I had the same type of thing in an older Mazda. The trunk would fill up amazingly high and I had to bail it out by hand after each rain. I got into the trunk and had my wife hose it down before finding that the taillight lens was not water tight.


I figured taillight-to-fender gasket first, until I discovered that most automotive lenses consist of at least 2 parts that are glued together. Lots of them leak where they are glued together even when new. They are almost impossible to take apart and re-glue, but that's where most of the water leaks happen, between the front and back sections of the plastic lenses.



Good luck finding your leak.
-L
 
So, I think I might have resolved the problem. I had two sources of water into the trunk.

The first was as noted water getting under the gasket at the front of the trunk and then being trapped at the back of the trunk and flowing over the back sill into the trunk. I think I have fixed that by adding a thin strip of ribbed EPDM weather strip along the outside vertical surface of that lip around the front of the trunk. The inside lip of the trunk lid weather strip engages this ribbed strip and so far seems to prevent water from getting under the weather strip. Volvo covered that lip with wind lace; but, only extended that wind lace up the sides of the trunk, ending about 100 mm before the corners at the front of the trunk. I think its right where the windlace ends that the water gets under the gasket because of the discontinuity. If Volvo had extended that wind lace around the complete periphery of the trunk water getting under the weather strip might not have been a problem.

With that source of water eliminated, I found that I was still collecting water in wells; but, it was not entering from around the trunk opening. After messing around with the garden hose for about an hour, I found that water was entering through the vertical weld seam that ends just above the trunk wells at the very back of the well. This weld seam runs right up to the bottom of the buckets for the tail lights. When the tail light buckets are inserted into the back panel and sealed in place the lip of the bucket overlaps and hides the top of the seam. On my car, the top of the seam on the left side was poorly formed leaving a small gap between the lip on the tail light bucket and the top of the vertical seam. To boot, the sealing of the bottom of the bucket to the rear body panel was incomplete leaving a gap there. With the trunk open and the tail lights in place I held a hose over the tail lights and ran water over them. In about 15 seconds you could see water running out of that vertical lap seam just above the rear of the trunk wells and running down into the well. Two minutes of doing this and I had about 12 mm of water in the bottom of the well. I was surprised at how such a small apparent gap could admit so much water.

The flaw at the bottom of the tail light bucket is not visible until you remove both the tail light lens and the bulb holder assembly which has the tail light gasket. Once the bulb holder assembly was removed on my car you could see the deformity in the weld seam on the left side that created the gap allowing water to enter the inside of the seam. The right side did not have that deformity; but, with your finger nail you could feel a fairly large gap between the bottom of the tail light bucket and back panel of the trunk. I purchased some clear seam sealant to fill the deformity in the weld seam and seal the bottom and up the sides of the buckets on both sides of the car. The sealant is hidden when the tail light lens and bezel is installed. The sealant is still setting up so I haven't had a chance to do a water test.

When I was doing the flooding of water across the back windshield with the trunk lid open, this problem of water entering the seam did not show up. With the trunk lid open the water flows down the channels on either side of the trunk opening and shoots out the back. With the trunk lid closed, the water flowing down those channels hits the lip at the very back of the trunk and then drains down directly over the tail lights. The trim bezel around the tail light lens does not contact the back panel of the trunk. It probably sits off the surface about 3-4 mm. This gap between the trim bezel and the back of the trunk acts as a perfect channel to direct water down and into the gap between the bottom of the tail light bucket and the body or that deformity in the seam that existed on my car.

I will note that in all my water testing exercises, I did not see any evidence of water getting into the tail light assemblies. The tail light gasket was doing a good job of sealing the bulb holder assembly to the lens. Not such a good job of sealing the tail lights to the body.
 
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