Car undertrays - are they worth the bother?

[stripped fred]

Every time I want to change the oil on my sharan I have to remove the bloody untertray. It's pain of a job because some of the fixings are broken. I suppose it only adds 10 minutes on but part of me things I might just bin it. However, the other part says that it helps to protect vital components and smooths the airflow giving me an extra 0.2mpg. My old Peugeot didn't have one and I didn't seem to notice it's absence. Any thoughts? Am I just being lazy or does it not really matter that much on an old, cheap car?

[Lacquer Peel]

Every time I want to change the oil on my sharan I have to remove the bloody untertray. It's pain of a job because some of the fixings are broken. I suppose it only adds 10 minutes on but part of me things I might just bin it. However, the other part says that it helps to protect vital components and smooths the airflow giving me an extra 0.2mpg. My old Peugeot didn't have one and I didn't seem to notice it's absence. Any thoughts? Am I just being lazy or does it not really matter that much on an old, cheap car?

http://www.ebay.co.uk/itm/191306569885

[Supernaut]

The undertray on my car sorted itself out.

 

It fell off. I didn't bother putting it back on.

[djoptix]

I took mine off the C5 and didn't notice any difference whatsoever (apart from oil changes being quicker).

[tooSavvy]

During a period of extreme weather a few years ago... Main road down Seaham way had a large, deep pool between two crests (not visible to oncoming).

 

I was gingerly piddling along in the van when a Golf/Bora thinggie absolutely 'planed' across it - got to be about 60+!

 

When the spray cleared/wipers cleared deluge... There was a complete Utray >> bobbing up n down in the pool

 

 

TS

[Guest Hooli]

Years ago a mate had a series of ashtray GTEs, they all ran cooler when driven hard with the undertray in place.

[Asimo]

Bin the damn thing unless it is in tip-top condition.

They can cause mayhem when they come off and go frisbee-ing across the highway!

[sierraman]

Throw the fucker away. It's usually my first job.

 

On an old car they can hide slight leaks as well, is sooner notice a small stain on the drive than run out of coolant on the M1.

[twosmoke300]

They keep noise down quite a lot I find . Look at a modern tdi one - loads of weird shape lumps and bumps on the inside - they must be there for a reason !

Keeps the engine / belts etc much cleaner too .

[dave21478]

If its not flapping and likely to fall off, then leave it.

30 seconds with a holesaw in your drill makes a hole big enough to access the sump plug and do oil changes without removing it.

[Steve79]

Convoluted undertray story!

 

I had to have the under tray replaced on my company focus. 50k on it and inherited from previous employee.

 

Because Lex Autolease are complete tight arses they recommend Halfrauds as a recommended service agent! 1st service at 12.5k, car gets taken there and the muppets leave the oil filler cap off. Cue oil absolutely EVERYWHERE. They get told to steam clean, but only do the top of the engine. 

 

I get the car with 25k on it and the bonnet soundproofing is so saturated in oil that if you pushed your finger into it it actually oozed out. Lex decide that the local Ford Stealer in Bristol who is Trust Ford (ironic because they can't be trusted to do anything right and their customer service is appalling!) should steam clean everything and replace sound proofing.

 

Now to the actual point! The undertray also had to be changed as it apparently incorporates a lot of soundproofing material and was absolutely saturated in oil.

 

Seems a bit daft to put soundproofing material into a component which is exposed not only the elements, but also anything leaking, spilt in the engine bay!

[chaseracer]

Any thoughts? Am I just being lazy or does it not really matter that much on an old, cheap car?

 

So... yes.  And no.

 

Welcome to AS, everyone.

 

[AMC Rebel]

I prefer to have them in place.  I bought some new fasteners for the MG one.

[bub2006]

My Peugeot 307 had one that was hiding a decent oil leak. It fell off after misjudging a kerb. Never replaced it.

[Hendry]

Mines went walkies and I replaced it, figured it kept engine bay components protected from the elements to a degree and also reduced engine noise.

 

The problem I now have is the underbonnet soundproofing is fucked and breaking off like bits of asbestos tile, and now doesnt stay tucked into the grooves for the slots on the soundproofing to slot into at one corner so amplifies the diesel engine clatter and totally eliminates any soundproofing advantage i gained by fitting the undertray.

 

OP: I would keep it, but id go and buy new fixings for it from VW, they are pennies, and when fitted with new fixings, itll be a doddle to remove and refit for oil changes etc whilst still keeping the advantages of having it. and when those start showing signs of going crusty/broken and going to be a bastard to remove next time, replace them again.

 

PS Steve79, I feel your pain re Halfords, my old work also used them for any work that wasnt tyres, bodywork, warranty or servicing on prestige badged cars. One of their mechanics actually got sacked for replacing a hub on our Fiat Ducato Transporter and making so much of a mess of it it was grumbling like fuck again a few days later and was wrecked meaning they had to foot the bill for a replacement again. 

 

They once serviced a Renault Espastic for us and we went to prep for it going out to a customer one day and the oil display Renaults have on the dash displayed a top up oil message, tapped the end of the wiper stalk and the wee bars of which for max oil level there are 6, was on 1, we manually checked with the dipstick and it was low, they forgot to top up with oil after servicing it, new filter etc. evident but no oil.

 

We also had a C3 Picasso which went for a service, one day en route to a customers house to deliver it, we noticed oil dripping from under the car, later found out it had been serviced by Halfords a couple of days previous when we checked back the records, put it back in and the manager (decent guy tbh, monkeys working as mechanics though) admitted to us whoever serviced it had cracked the oil filter housing.

 

We stuck with them though because they honoured the agreement we originally had with Nationwide Autocentres before Halfords took over and inherited their contracts. 

[UltraWomble]

Almera doesnt seem ever to have had one - C8's was OK for a while but gradually started to break and last oil change got binned.

Engine gets a bit more muck from the road, and the driveway gets an oil spot where it drips. I can live with both.

[Dick Cheeseburger]

I think undertray is a euphemism.

[Hendry]

Almera doesnt seem ever to have had one - C8's was OK for a while but gradually started to break and last oil change got binned.

Engine gets a bit more muck from the road, and the driveway gets an oil spot where it drips. I can live with both.

 

My car has these other plastic undertray things that run along the side of the car meeting the underside of the sill, im not sure of the point of them but they are going brittle and breaking off into bits, maybe its a way of stopping salt and dirt getting into the underside of the car thus slowing down rust, at least these never need removed so the half of them there is left can stay there until they totally fall off then I may consider replacing them. They must serve a purpose but I cannot even guess what that may be. 

[New POD]

On the m2 mx5 and the Mk1 zafira, they are great at hiding rust, so much so that it is my understanding that the DVLA have sent bulletins to MOT stations telling them to inspect underneath them.

[HMC]

I often see them held on by a few too few fixings flapping like mad on the motorway, making such a racket even I can hear it above everything else. I rate them but wish they'd leave a little flap for access to the sump plug, For diy philistines without a pela pump.

[castros_bro]

Hi Mods   

 

Would you kindly move this to Mumsnet where it belongs? 

[Bren]

Good for catching spanners and sockets and keeping oil off your drive.

[MikeR]

My Zafira oil burner  had a load of rust hidden by the undertray , it also got in the way and flapped around , most of it ended being cut away to get at things and to remove the sound deadening foam that held water against the subframe .......  the Meriva did not have one and neither does the Focus both of which are petrol , so I  assume they were more of a sound deadening tool for oil burners ... 

[FakeConcern]

A few years ago there was a lot of discussion on the C4 Owners forum about undertrays and how you really needed one better MPG ,Citroen went to a lot of trouble to design & make it, they wouldn't fit them if they weren't needed as they cost a lot of money blah blah etc. Anyway as I was doing 30k miles a year in the VTS petrol I decided to get one. It made absolutely no difference I could notice, MPG the same, time to get up to temperature, the same, wind noise the same. PIA to change oil.

Later on I was looking at the cars build spec on Service Citroen and my did not have one fitted as new!

 

Needless to say, I won't be fitting one to my new VTS!

[stripped fred]

So, a mixed bag then. I'll stick with the bloody thing for a while longer I think. It does sound a bit quieter with it in place.

[mrcitroen]

My Xantia HDi Exclusive had a wee handy hinged door for draining the oil. What a handy but simple thing. The Alfa on the other hand has one hell of a massive under tray with a zillion bolts holding it in and no cunning trap door. Oil changes are a bugger on this without a vacuum extractor.

 

Not surprisingly neither the GS or BX have such a thing as an undertray which is a bonus.

[Magnificent Rustbucket]

Years ago a mate had a series of ashtray GTEs, they all ran cooler when driven hard with the undertray in place.

 

 

I was wondering exactly that. Quite a few cars run hotter with the radiator cowling removed. Taking off the undertray could have a similar  effect in negatively affecting proper airflow through the radiator.

[They_all_do_that_sir]

Always take off for first service in my care and chuck.

 

Our old 307 decided to try and shed the undertray at 60mph on a country road. The previous keeper had attached the front of it with shitty cable ties which promptly gave up. Sorting that out in the pissing rain at the side of the road was fun.

 

I like being able to leave the "cardboard of truth" under a car to pinpoint leaks. Cant do that with an undertray.

 

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[Guest Hooli]

When I get around to buying bolts that fit I'm putting the undertray back on the Saab.

[stripped fred]

With mine it's not the fixings as such which are at fault. There's four bolts that go though mounting holes in the undertray and some of them have ripped so no hole left to speak of. I've tried using big washers with some success but it's a faff.