Motor cover

Szegedi · Unread post by **Szegedi** » 07 May 2005, 23:52

Yesterday, on highway, driving 130 km, I've heard terible noise which ressambles flat tire. I've pulled over and looked and found out that plastic? protective cover which is below the motor simply broke up. I have removed remaining parts. My mechanic is convincing me that I could freely drive without it but I am concerned. Any comments?

oilyspanner · Unread post by **oilyspanner** » 07 May 2005, 23:57

Most Xantias I meet are running without the cover, many people dont put them back properly after work on the car, you will not have a problem.
Stewart

Kowalski · Unread post by **Kowalski** » 07 May 2005, 23:58

My older Xantia has it's undertray while the newer one doesn't.
What difference does it make?
None whatsoever as far as I can tell.

nick · Unread post by **nick** » 08 May 2005, 00:13

I think the idea was that it was supposed to reduce engine noise from outside the car, but I can't say I've noticed Xantias with the undertray in place are any quieter than those without.

Unread post by **Peter.N.** » 08 May 2005, 00:58

The only useful purpose it seems to have is to keep the bottom of the engine clean, my first XM had one but the last three havn't and they are a lot easier to work on!

Homer · Unread post by **Homer** » 08 May 2005, 01:22

Undertray?
Niether of mine had one and I don't remember it mentioned in the BOL
Could it have been an optional accessory?
I know the first GS my dad owned had one because it caught a spark plug which ejected it's self. I don't recall them being present on the two we had later which I worked on.

Kowalski · Unread post by **Kowalski** » 08 May 2005, 01:33

Supposedly it was to reduce noise reflected back at the car from the road surface, making the car quieter. The later Xantia I have is quieter without it than the earlier one with it, but the later one has also done less milage and has an pump with electronic timing control on it.

fastandfurryous · Unread post by **fastandfurryous** » 08 May 2005, 01:53

These undertrays are supposed to serve 2 purposes:
1. Reduce the amount of engine noise reflected off the road. This is only really effective on longitudinally mounted engines.
2. Improve airflow through the engine bay, by creating a very slight pressure drop under the engine bay, air is effectively "sucked" through. This effect is barely noticable, and as soon as the tray sags a bit with age is completely negated!
Pug 309's had undertrays from new, but 99.9% of them have either fallen off, or been removed. A friends 309 still had it's undertray fitted when he got it.... until the rush of air under the car caught it and ripped it off on the M4 a week ago!

Homer · Unread post by **Homer** » 08 May 2005, 04:45

I had my 2nd Xantia from two and a half years old. Citroen maintained.
I suspect if you check round the back of any citroen dealers there is a big pile of almost pristine undertrays. Removed at the first service by lazy mechanics who realised they were creating two jobs for themselves by replacing them.

Kowalski · Unread post by **Kowalski** » 08 May 2005, 05:33

The undertray on my Xantia has a door cut into it with a little catch on it. When you change the oil, you open the flap and close it afterwards, i.e. the undertray doesn't need to come off.
When I did the cambelt and when I did the clutch the tray had to come off. Taking it off makes access to the exhaust bolts easier too, but those times aside it shouldn't need to come off for any regular maintenance.

Homer · Unread post by **Homer** » 08 May 2005, 07:38

Having never seen one I wouldn't know about little doors.
Still...
Open door, close door. Repeat at next oil change. That will knock your mechanic off his efficiency rating. Can't go taking an hour to do an hours work.

citronut · Unread post by **citronut** » 08 May 2005, 16:05

i think it EEC rules to help to stop fluids droping on road,they seem to soak an auful amount of leakage from engine up ha ha regards malcolm

rbruce1314 · Unread post by **rbruce1314** » 08 May 2005, 16:16

When my xantia came back from its last service (yes I know I'm lazy) it didn't feel "right". It was a bit more noisy and handled slightly more skittishly (is that a word?) on cornering. You've guessed it- they had forgotten to replace the tray. So my conclusion is that it must make some difference since this was a "blind test" i.e. I didn't know I was doing it!!!

SSidhu · Unread post by **SSidhu** » 08 May 2005, 23:50

From where i come ,it is a tropical climate,at 30-35C daily.
For Xan TD's an uphill climb or high speeds will see water temp
going to 95-100C, I hv disconnected the heat exchanger water hoses
and now temp is around 80-85C, and I hv also removed undercover
for better airflow coz engine compartment gets too hot...but oil
temp goes high when stressed or hillclimbing may hv to fit a oil
cooler...

Kowalski · Unread post by **Kowalski** » 09 May 2005, 00:48

If you disconnect the oil cooler hoses, where do you expect the heat from the engine oil to go? Turbo life is dependant on that oil cooler cooling the oil since the oil is used to cool the turbo.