Noisy exhaust on cold start!!

rk696 · Nov 29, 2008

This is a problem I have had with the toledo ever since I have had it. When I start her up from cold, the exhaust system is really loud for a couple of minutes until the choke comes off and the revs return to normal, then the noise disappears.

It sounds almost as if a baffle is loose in the exhaust somewhere, but it doesn't do it at all when the car is warm..

I've been searching around, and have read about the secondary air pump thingey. I thought it may have been this. Does my car have one? It's a 2001 Toledo 1.8 20V N/A engine (AGN). I've had a good look around the engine bay, but I can't seem to find it..

Any ideas?

car_guy143 · Nov 29, 2008

My 99 T reg v5 150bhp has a secondary air pump, i think all Toledo that came with a Catalytic converter have the secondary air pump. It is used to blow hot air from the engine over the Cat to get it upto operating temperature faster. All to do with emmisions control really as the cat doesn't work as well when it's cold.

When i start my car first thing in the morning you can hear it start just a second after the engine fires up. It does turn off after a couple of minutes of driving though. It sounds like yours is doing the same. Must admit the first time i heard it i thought there was a problem with my car! lol

rk696 · Nov 29, 2008

Hmmm.

Do you have any idea wherebaouts on the car it is?

I've looked all around te engine bay and I can't see it. AFAIK on the leon it is just behind the radiator, next to the oil filter.

car_guy143 · Nov 29, 2008

Not sure i'm afraid. I've not had my Toledo that long to be honest, only about two weeks. I do notice the air pump noise every morning though as i work at 6am so it's really cold at that time of the morning.

rk696 · Nov 30, 2008

Oh well. Might post in the leon section. See if anyone can give us any clues..

DannyC87 · Nov 30, 2008

just a thought, if it is a stainless exhaust which is clamped together it could be related to the expansion of the steel with heat. basically when the exhaust is cold it shrinks and the joints are no longer a tight fit so they rattle a bit; as soon as the metal gets hot it expands and the joints lock so no longer rattle.
might not be this at all though!!

rk696 · Dec 1, 2008

It's funny you should mention that Danny, just took the car to kwik fit (Exhaust under warranty from previous owner :thumbup:

), and apparently it had the wrong size clamps on it and was leaking at the joints. So they lathered it with assembly paste and put the right size clamps back on it. Made the exhaust a bit quieter, but still really loud on cold starts.

I doubt it's a stainless one anyway, knowing kwik fit..

rk696 · Mar 2, 2009

Videos!!!

Sorry for reviving an old thread, but I've put a couple of videos up on youtube which shows you how loud the exhaust is.

http://www.youtube.com/watch?v=3BYV-OcvUxg

http://www.youtube.com/watch?v=QHihnpxU9ik

It's definitely leaking at the joints where sh*t-fit put a new centre section in (NOT MY IDEA!!!), but could that cause it to be so loud?

I would appreciate it if you could watch these and let me know if it sounds normal or not.

Cheers! :funk:

seattolsports · Aug 2, 2009

Another thread back from the dead!

My Toledo does this as well during cold mornings. I took it to my very respected local garage who confirmed no leaks on the system but did replace the heat shield for me at very little cost only because he took it off to check the pipes and it fell to pieces!

I have checked the exhaust myself as well and as far as i can tell ive no leaks but if anyone can claify this as a design point then i can stop moaning to my mrs about it!

meltonlad · Aug 2, 2009

ive got this prob to. but mine sounds like ive got a blowing exhaust near the cat but onlt from cold. taken it to sh*t fit and all ok no leaks.

rk696 · Aug 2, 2009

Wow, didn't expect anyone to reply.. It's nice to know it's not only mine which is having problems..

I think I may have found out what the noise is. The engine (1.8 20V) has Variable valve timing, and apparently from what I've heard, the ecu opens the exhaust valves earlier which effectively lets pre-burnt fuel mixture out of the cylinders and into the manifold, warming the cat converter up faster, hence the noise. I think...

meltonlad, my noise sounds like it's coming from the cat too. Since i posted earlier, the leaks have been sealed, but the noise is still there.

seattolsports · Aug 3, 2009

I have the 2.0L 8v and after chatting to Seat in Sidcup earlier (Needed to buy a new interior light and i could not find one on eBay) I have been told it is a function of the engine and the only way to stop it is to, and i quote.... "buy a very expensive Stainless steel exhaust from seat with a differant designed cat"

I think i now like this cheap noise!

jase20vt · Aug 3, 2009

my cupra as similar problem, but iv read over on golfgti.co that the exhaust manifold gaskets can blow from cold, but for the short time its noisey its not worth the replacing £30 ish gasket

rk696 · Aug 4, 2009

haha, seattolsports, I love the cheap noise too. It definataley makes the car a head turner when it starts.

jase, that sounds like a likely candidate where the noise is coming from. I might try and have a look round the manifold when I start it in the morning..

blackcupra180 · Aug 4, 2009

lol mines is the same too 52 leon but doesnt bother me enough to try fix it

xnox202 · Aug 9, 2009

Now this is a surprise. Even though with my 2.5" and aftermarket exhaust, the same buffling/chattering sound of air escaping is also near that down-pipe too when cold.

Please report back if you're getting a exhaust manifold gasket. Hope it fixes the little problem. Pretty annoying TBH, well that's just me.

rk696 · Aug 9, 2009

Right!!

Had a look around the exhaust gasket in the engine bay on a cold start, and as far as I can see, it doesn't leak. I've tried listening through a piece of pipe near it and holding a piece of paper near it.

Also, according to elsawin, my engine (AGN non-turbo) doesn't have a secondary air pump which explains why I can't find it.

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