Is an exhaust heatshield an MOT requirement?

[AdamW]

I had the heatshield of my backbox start dragging on the road a couple of months back. I went to get the backbox replaced, but the exhaust centre whipped the remainder of the shield off and said "Nah, doesn't need replacing yet, there's life in it yet!".

I'm having it MOT'd this weekend, so what I'd like to know is, will the lack of an exhaust heatshield be an MOT failure? If so, I will get a new backbox fitted at an exhaust centre for a lot less than Vauxhall want, before taking it in.

 

[jonnyfishing]

Try any of these..

www.motester.co.uk

or

www.ukmot.com/malcolm.asp

or

mot test uk

 

[nstreet]

If you have a plastic petrol tank and the exhaust runs by it, the heat shield is there to prevent the tank from distorting, melting or causing an explosion. I would think it would fail if this is the case.

 

[AdamW]

It's funny you should mention that, my engine died on me this morning, had all the hallmarks of a fuelpump failure (engine turned over but didn't start)... 30 seconds later I could start it again. Mentioned it to my mum just now and she says they had a car that did that and it was due to the fuel pump getting heated by the exhaust. I'll be checking the Haynes manual to see where the fuel goes near the exhaust! The heatshield is on the UNDERside of the exhaust, so shouldn't be causing this though... I might just have a knackered fuel pump (apparently the same thing happened to my mate's dad's car a few weeks back).

I spoke to the Vauxhall garage re: the missing heatshield. They said it should not constitute a failure, they are only concerned with perforations to the exhaust (i.e. if it is blowing). £115 all in to replace it, not as bad as I thought but I think I will take it along to an exhaust centre and get them to check if they think it is blowing, and see how much they want... If I know there's a problem I might as well get it fixed first!

The website Jonny links to says "The exhaust system will fail the MOT if part of the system missing or excessively deteriorated"... I guess that is up to the interpretation of the tester, but I think this might count as a part missing, or deteriorated.

 

[pipme]

....Engine cutting out is normaly a symptom of the crank sensor failing
Also worth checking for vaccum leaks and giving the idle valve a good clean.....

LINK ??

 

[AdamW]

Dunno why I didn't try googling: I guess I just trust you lot all so much!

Cheers for the link, Pip. With this guy it seems to have been a dirty idle valve that did it. Sounds a lot cheaper than a crank sensor!!!

I'll get the mechanic to give it a thorough diagnostic'ing on Saturday.

Googling shows up all kinds of things that cause this, everything from fuel injector relays to the ignition coil amplifier... the idle valve is the one that has cropped up most though.

Just a thought, but seeing as it has only happened the once (touching every piece of wood I can!), I could change any number of parts and not know if I've fixed it. I reckon that if no errors show up at the garage (no diagnostic warning lights came up on the dash) then it is probably not a sensor: these are usually easy to build diagnostics into so would show on the dash. So, if Vauxhall can't find a problem I'll keep on driving it until it happens again. That way I might be able to build up more of a pattern (I've got a Haynes manual and I'm dying to use it!!!)

 

[pipme]

Several years ago a hitherto non-beat missing Nissan, suffered engine cut out on the over-run approaching car park at work (following 20 odd mile run) ... After a while I was able to restart ... never occurred again. The car was carburettored, the consensus of opinion was a momentary problem with the valve which turns the fuel supply off in 'over-run conditions ( the ORFCO valve is/was a fuel saving device (supposedly). Basically when your foot is completly off of the throttle, and the revs are over 1500 rpm it activates a little solonoid in the carb which cuts all fuel to the engine) ... Problem item unproven. I cannot imagine any such valve on a fuel injected engine, probably built into engine management system ... perhaps connected to possible crank sensor probs?

I Found no 'fluff or fine wire wool' around the jetting in carb .. Not really expected as Nissan use relatively large separate filter. No apparent water in fuel... Used different petrol station for a couple of fill ups.

Nissan dealer unable to cast any light following inspection.

Just glad it did not happen in a dangerous place .. like the outside lane of busy MoWay or joining fast flowing main road (no hard shoulder). Certainly allowed a little extra space until confidence returned.

Another link.
http://66.102.9.104/search?q=cache:...-20/4d9f4d76.html+vauxhall+crank+sensor&hl=en
A little 'iffy', correction, almost totally 'iffy' forum but is an ominously long thread .. there may just be the odd post or three which points the way .. Or maybe not !! ....
If the talk is provably ECU, assume the position, wallet held upside down, or go 'breaker' route

Re: Exhaust, down the years I have found the 'factory' or 'works' model to have greater longevity (a Peco full system copy was quality in 70's)... Unless the dealer used same as QF etc. .. But then, I must say, the wife used QF, pre company motor, due to their lifetime ownership guarantee, don't know if that still exists. They replaced her shopping trolley's rear section twice over following 5 yrs for nix ! Apparently the 'guarantee' was a worthwhile customer grabber for them... worked well for us back then in the 90's
QuickFit may advise.

 

[AdamW]

Exhaust sailed through the MOT, no problem. I better remember not to park on any dry grass (isn't the shield there to stop igniting such material?)

Stalling engine turned out to be the EGR (exhaust gas recirculation) valve. Part of the emissions control system. Presumably it was either detecting the emissions were bad and killing the engine to prevent me harming the environment, or the valve was causing excess back pressure and stalling the engine. The latter seems likely as the car was fine until it reached idle speed.

Weird thing is, I had this replaced exactly 12 months ago. The last time it was under warranty, which means this one didn't come free (because it wasn't a repair I had paid for before). £140 all in to replace the valve.

So, a £500 service and MOT in all.

They did clean it inside and out though