406oc.co.uk

Set about me first 406 oil change yesterday. Undid the 4 x 1/4 turn screws easily enough - undertray is tiny & lightweight compared to the Xsara, (which extends past the back of the engine compartment - whereas my '6's is in two sections split at the rear of the sump). "What's all the fuss about", thinks Doggy, "just undo this here M6 screw at centre front... ". Snap! - sheared said screw off (only to find it didn't really need to come off)

Anybody know a fix for this that doesn't involve drilling through the oil cooler, condenser or anything else pricey?

Any chance of a 'growl' emoticon?

I don't expect undertrays to re-attach. The captive nuts usually end up rusted to hell so I just use zip ties to put it back on, with just a few little holes drilled in it to give the ties something to wrap around. some have reported the zip ties have given up and they've lost their undertray, so I'd suggest adding a few more fixing points for it

Ditto, zip ties utilising existing holes for the previously occupied "screws". 100% attachment rate so far

i wouldn't trust zip ties, but mine has had the samee zip ties on for 50k so maybe they can be ok

in the end i chucked mine in the bin, more trouble than its worth

406silverhdi wrote:in the end i chucked mine in the bin, more trouble than its worth

My last 406 had no undertray and a big pile of steam came out everytime i went over a puddle. Had to turn off the check engine light after every time it rained

Neither of mine came out the fctory wearing them and I can't say I have any issues

Neither of mine did either, they've both got the rusted remains of the screw shanks though

steve_earwig wrote:Neither of mine came out the fctory wearing them and I can't say I have any issues

Perhaps the ones without the undertrays have been modded in the factory to deal with that.

Yep,
When you get a 406,
Tax, insure, V5 sent...bin the undertray.
You can then see leaks before its too late and keep the engine from overheating.
Take it from me they're more trouble than they're worth and dont affect the economy.
How many cars do you see with them flapping about and the hapless owners with panic on their faces?
405's never needed them...

T

Use "hostage grade cable ties".

Never fails! LOL

lofty wrote:Use "hostage grade cable ties".

Classic!

Thing is, I got my 4 quick-release screws back in OK , just couldn't see an easy fix for the M6 screw front & centre

Thanks everyone

Hi all.

I can not help thinking that the undertray must stop some road durt and rubbish getting onto the engine electrics. And the dryer you keep French electrics the better. But then some cars have never had them and work fine. Since mine has always had one, I think I will keep going through the painful process of taking them on and off every time I change the oil. Which is the next dry day now.

Regards,

Richard.

The undertray does perform an important aerodynamic function too in that it helps with the air path from the back of the radiator and down the bulkhead/turbo area.

Tie wraps and washers worked a treat for me until my garage had a go and weren't so diligent

One large drift of snow later and it was gone

Car's more noisy now too

I seem to remember seeing some tests on an Aussie forum where they reckoned it helped with both cooling and inter-cooling.

Still,one thing less to fall off...