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Old 5th October 2012, 02:03   #1
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Exclamation Plenum Check - The Reason Why **ALL OWNERS PLEASE NOTE**

Plenums we hear so much about them and the reason why is very clear below in the photo's that follow.

And even more important this time of year with the Autum leaf fall etc.

Yesterday a member of the club Mike came to have his handbrake mod fitted, as i always do i checked the plenum's after asking if he had checked them it turned out he had only brought the car Sunday so the car was very new to him, he had looked at the plenums from the drivers side and could see some water and he also heard the sloshing sound when driving.

The results can be seen below so come on gents lets keep on top of these plenums do the spyhole mod and its only takes 2 minutes to check for water once applied.

Pic 1 water at least 3" deep

Pic 2 The water must have been deeper at some stage according the the pollen filter marks

Pic 3 starting to rod the plenum tube to clear the soggy leaves and dirt which as bunged up the lower tube

Pics 4 the water starts to flush out of the plenum this went on for at least 2 mins

Pic 5 Still pouring out strong

Pic 6 slowly stopping with the rain we have been having this so easly could have been worse ECU damage which would have been a crying shame as this MGZT as only 20000 mile on the clock.

Pic 7 All the water drained away this should not happen again as the spyhole mod was put in place and Mike shown how to rod them each week at the same time as checking his oil water etc.

So lets get checking the plenums right away there is no excuse not to, all the best Arctic.


This is how you can check your plenums if you have never checked them before this is mainly for new members that is why i have put this thread together so it is all in one place on how to check and also add the spyhole mod & leaf stopper/collector if you so wish, in my opinion worth doing.

This is the windscreen scuttle panel/outer grille which will have to be removed to start checking the plenum for water ingress below Fig1

First peel off the weatherstrip up to the wiper fixing point at least Fig2

Now you can press in the plastic spring clips to remove the grille panel Fig 3

This will then allow you to remove it and store it safe for the time being Fig 4

Next step is to remove the front screw/clip sometimes you may have to prise this up if it will not screw out.Fig 5/6

Now removed put this safe also

Next prise up and remove the rear scuttle clips hold your finger over the top because these can fly off sometimes never to be found again Fig7/8


Remove the first three of these and again put them safe for re-fitting after Fig 9/10


This will now allow you to lift the front of the scuttle and get access to the shield panel tray which needs to be removed. Fig 11

You can grip and remove the shield panel tray and slid it carefully out from its recess Fig 12/13


This now exposes the lower plenum and pollen filter area this is also where the ECU resides and can get damaged if water is allowed to build up because of the blocked plenum tube Fig 14

Here you can see how i have rodded the tube with my choice of rodding tools a plumbers spring pipe bender 10mm or 15mm also note even though i check these every week that because of the deluge of rain we have had this year and month water is still getting to a certain height from the line seen on the pollen filter, this was empty when i took these photo's but must be filling even though clear because of shear volume of water Fig 15

This shows the rodding tool i use pipe bender with a boot lace and plastic tube the reason why will be seen later in the thread. Fig 16

The shield panel tray can now be re-fitted back into place Fig 17/18


This photo shows the spyhole mod so the plenum cab be checked and rodded in the future with out having to remove the scuttle clips and trays. Fig 19

Here you can see the rodding tool again in use showing why the lace and plastic tube is needed because the plenum is at least 24" deep Fig 20/21


Here you can how the spring as come all the way through the plenum and the tube until it reaches the ground under the car Fig 22

Once rodded and if you have the spyhole mod in place fit a rubber 25mm bung which can be easily removed rodding in the future Fig 23

Replace the front screw clip Fig 24

Replace the three scuttle back clips Fig 25/26


Next replace the rubber weatherstrip Fig 27

And last of all with the job finished refit the windscreen grille panel Fig 28/29


The plumber spring i use with lace and plastci tube attached for the extra length needed to get to the bottom of the plenum 10mm or 15mm obtained from Toolstation, Screwfix, B&Q etc Fig 30

Roding the plenum

Spyhole Mod Continued At Post 21 Click the Link
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Last edited by Arctic; 26th November 2019 at 11:32.. Reason: photo bucket theft
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