2005 XC90 Plenum Leak prevention (CEM prevention)

[cn90]

...TNN looks like this: http://www-odi.nhtsa.dot.gov/acms/cs/ja ... 44260P.PDF

Thanks for the link, ggleavitt.

I currently don't have any issues (not yet) with water leak or with CEM, but I would like to prevent this issue.

I have a few questions that hope some gurus can answer.

1. If I have no water leak, should I address this?

2. I have the old setup (mine is 2005 XC90):

- Just looking at it, I don't see how water can get in if one clears the big drain from leaves. I keep this area clean all the time.

What I can see is:

- At the BASE of the big drain area, there are small holes for water (which comes from the roof, windshield glass areas) to drain. If you peek down there with flash light, you will see the small holes at the BASE of the big drain.

- Once the small holes are covered with debris, leaves, water will pool there, once it reaches 1 inch tall, it will overflow into the BIG drain.
But by that time 1 inch of water is there, it is enough to leak into the base of the Plenum Box (where the 4 bolts hold it down). Is this correct?

- So if one clears leaves all the time, can one run into water leak issue?

See attached photo, so does water comes in at:
#1: rubber connection
#2: rubber connection
#3: lid: but how...the lid sits high
#4: base of the Plenum Box (where the Plenum Box meets the body)?

XC90-Plenum.jpg (137.46 KiB) Viewed 4132 times

[cn90]

So, I think I found the answer to my own post. See the NHTSA document below:

http://www-odi.nhtsa.dot.gov/acms/cs/ja ... 44260P.PDF

Basically alternating freezing rain, rain combo is the root cause.
So, as long as I don't park outside during freezing rain, I am OK...

[sandsandsand]

Here is an article about the issue:
https://volvo-p2-stuff.blogspot.com/202 ... water.html

[ggleavitt]

Have to be honest, were it not for the fact that I had already purchased the rework kit and felt compelled to install it after 2 years on the shelf, I likely would NOT have expended time and energy to do so. CN90 is correct in my opinion, water ingress appears to be a combination of freezing temps and standing water that cause the primary issue of leaking and the rework kits is a total PITA to install. With this in mind and in retrospect, I might have simply lifted the cover bottom while it was dry and squirted silicone around as a bead between the cover bottom and the car body, then crank everything back down. I believe this approach would do as well a job as the rework kit to keep the CEM dry.

Thanks for posting the write-up, will be informative for XC90 users as well as for the other P2 vehicles which were affected.

[oragex]

The blog mentions an interesting thing about the newer CEM water ingress: car being parked (or travelling) on a steep incline during heavy rain, perhaps with the front of the car 'upwards'. Possible in this position the wiper motor area gets filled with stagnant water that cannot drain through the large drain hole shown in the pics, causing water to rise and to leak inside the plenum box. The two large drain holes actually have each small passages that may get blocked - I show it in this video at min 2:00 www.youtube.com/watch?v=rzpaJ4ulRic There are also 'flaps' at the bottom of each hole, right under the firewall behind the engine, worth making sure they are clean of debris - little probable unless parking the car under trees such as pines

[ggleavitt]

See https://forums.swedespeed.com/showthrea ... ost4415369 for a variation on the theme, this time a vehicle that had been regularly parked under a pine for years and while I thought I was was pretty good about keeping the cowl screens clean, I did not pay attention to the bottom flaps ( I figured that out later on subpost #17). Super heavy directional "dump" of rain and vehicle parked a slight forward incline just as described above, mine flooded the passenger side. Caught it early so no long term issue but I'm a firm believer now in periodically getting under the vehicle when it's safe and checking that flap bottom to make sure the drain path is open.

That and the integrity of the spring loaded bottom cap on the 3-way washer tee under the passenger side hood, especially if you have a V8.