450SEL Air cond

[AAB]

The air conditioner in my beloved 450 has decided to leak water onto the floor in front of MrsAAB.

Any clues as to where I start to look,....as I am only clued up on replacing A/C compressors, & I would appreciate some guidance as to how to rectify this problem.

Regards,

Alex

 

[TJ 450]

Sorry for the bad news, but it is a reasonable job.

It will be the condensate drains at the base of the HVAC unit. They are accessable with the centre console removed and are probably blocked. Also there is a remote chance that the HVAC unit's housing is cracked.

Tim

 

[KenM]

I've got the exact same thing with the '75 450 SE that I have recently purchased. Fortunately for me it is only a recent occurrence and there is no rust in the floor pans at all. I have bought the heating and a/c manual and have been looking through it, as TJ says it seems as if just getting to the drain will require removal of the console. One thing I did find out is that there were an early and late version of the drainage system, the early only had one drain point and on the later they fitted a second, obviously to cope with the amounts of water. I haven't started to attack mine yet, except to get the floor mats and sound deadening up, which is critical because that stuff holds water like you wouldn't believe, it took a week of mine hanging in full sunlight before they dried and by then they had shrunk to about 1/3 of their thickness when I pulled them out, massive sponges.
Cheers,
Ken

 

[WGB]

It is likely only to be blocked drains and they should be visible from under the car as rubber tubed coming out oif teh transmission tunnel around the bellhousing end of the transmission.

Some judicious probing with string trimmer plastic or such like should liberate a faceful of smelly water.

Bill

 

[AAB]

Many thanks for the prompt replies.

Tim, by the " centre console " you do not mean the whole hump do you ( I hope !!!) but the bit with the knobs on ?

Will get onto the job ASAP, but it is a bit warm outside, so will probably attack it over the weekend.

Regards,

Alex

 

[TJ 450]

Yep, I mean the whole thing.

I would try WGB's trick first though, but there isn't much space under the trans tunnel without a hoist.

Tim

 

[BAR]

By far the quickest way, if you can get the car off the ground, is to locate the two drain pipes either side of the transmission tunnel.

A small plastic tube can then be inserted and in most cases will clear the blockage.

If you are lucky, you could try lifting the sides of the ccentre console near the firewall (this will be the flexible carpeted section. You may be able to see the rubber hose pipe that runs down from the a/c duct into the tunnel - if so pull the hose out and attempt to clear the blockage and reinsert it.

 

[6.9forever]

Have had the same thing with my 6.9.

There are three possible causes in my experience. Investigate them in this order:

1. The rubber drain hoses are most certainly accessible without removing the console if of the type I have on my 78 model W116. You do have to unscrew the trims under the glove box and under the steering column tho' and insert yourself head first into the footwells equipped with a good torch. Locate the rubber tubes, pull them off and clear them. Re-attach. (I suppose you could also access them from under the car as WGB rightly says but I went in through the car's interior instead, as described).

2. Also check for excessive refrigeration which leads to condensation in humid weather that then drips into the footwell. To avoid, do not wind air-cond dial past the re-circulation "notch" mark on the blue-printed dial.

3. The plastic moulding that the drain tubes attach to is relatively old, brittle type black plastic so a crack is conceivable, requiring repair or replacement, tho' unlikely.

 

[6.9forever]

...as a follow-up, wet W116 floor pan insulation is not worth keeping. It is sticky, smelly, mucky stuff and the floor will rust. The first point is under the accelerator pedal and also a lower collection point in the aft foot wells. I chucked mine out and replaced (courtesy House of Styria) with Dynamat and the smell is forever gone.

 

[chrisp]

Sounds like this is a common issue - I have it too.

Regards,

Chris

 

[AAB]

Did a check on the two drain hoses,..definitely not blocked up,.also poked a wire into the plastic pipes & they were clean also.

I was able to access the 2 hoses, (each only about 100 mm long) by carefully pulling the flexible console sides clear.

Not much drama except the driver's side, where you need to be a bit of a contortionist.

Regards,

Alex