loud blowing on cold startup?

[lloyd1986]

recently brought a very high mileage leon cupra last week, got it for cheap so didnt really mind,

seems to be one problem though, every startup it seems to have a loud blow coming from the downpipe area then after about 5-10 mins when it warms up its as quiet as anything.

is this more than likeley a crack or something in the downpipe? and when its getting warm it re-seals itself?

also engine managment light is on and have a reciept from seat saying its been on the computer and tyhey found that its the lambda sensor.

could this cause the blowing noise or am i just being thick? lol

thanx

 

[Cowie]

Is the noise definitely coming from the downpipe area,and not the front of the car where the SAI pump is located,this can fall apart where the rivets holding it together give way,causing it to sound like a tractor when the car starts,it then stops after a minute or so,just a thought,on the off chance it is this problem,here's a guide to fix it mate
http://forums.vwvortex.com/showthread.php?3820606

 

[lloyd1986]

ill have a listen tomorrow, that seems easier than changing the bloody exhaust manifold ! thanx for that quick response and link mate much appreciated.

 

[Cowie]

ill have a listen tomorrow, that seems easier than changing the bloody exhaust manifold ! thanx for that quick response and link mate much appreciated.

no probs mate,just follow the 2 'corrugated' black plastic pipes down in front of the inlet mani,these connect to the SAI pump.

 

[lloyd1986]

really hope it is this , but im 95 percent sure its exhaust :-(

if it does turn out to be exhaust , is there a guide or anything with pics of how to do it?

i got given a manifold by the chap i brought the facelift bumpers off but its one of them crappy shiney things off ebay , rather get a standard one than put that on lol

 

[twenny]

hi loyd mate ,

i found the sai system sounded like a hoover !!! when mine went .

next time its cold just cheack you turbo to manifold bolts ,they can work loose allowing exhaust out (that you can feel too ) and causing lumpy idle and lots of noise , that would be my first check bud

right under the charge pipe at back of engine in the middle theres 3 bolts , mine was the one nearest to the engine and the most awkward to get at , made quite a difference .

hope this helps

twenny

 

[traumapat]

lambda sensor sits on the DP... is it leaking from the sensor?

 

[lloyd1986]

only just noticed these two posts.
checked that black canister and thats is fine . :-(

i checked feeling for blowing down the back but could really feel anything. it seems to blow for around 8-10 mins on startup then sort of seal itself?? weird

how much of a ball ache is it to drop the manifold off to check it over and possible change both gaskets?

also i was meaning to change the lambda sensor just to get the managment light off, how bad is that to do ?

thanx for the replies.

 

[cupraslayer]

only just noticed these two posts.
checked that black canister and thats is fine . :-(

i checked feeling for blowing down the back but could really feel anything. it seems to blow for around 8-10 mins on startup then sort of seal itself?? weird

how much of a ball ache is it to drop the manifold off to check it over and possible change both gaskets?

also i was meaning to change the lambda sensor just to get the managment light off, how bad is that to do ?

thanx for the replies.

Cracked my manifold. Wasn't a easy job to get it off. Cost me' 120 plus the part.

 

[lloyd1986]

found a crack in mine , this morning !

so at least i know what it is now .

cant manifolds be welded?

 

[cupraslayer]

Yes they can. Pends how big it is and where tho. Mine looked about 3cm long , but turned out to be all the way round. Went for a new one in the end.