Hissing on hard acceleration and oil on underside of car

Blakey

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Hi All,

I've been hearing a hissing noise on my w203 when accelerating hard recently, and on inspection I found there was evidence of oil on the underside of the sump guard. I am hoping that all that is wrong is a split pipe or worn seal on parts 30, 60, 70 or possibly a holed intercooler (10) in the following link...

http://www.detali.ru/cat/oem_mb2.as...062r023835&CT=F&cat=65F&SID=50&SGR=200&SGN=03

Are there any common failures of the parts indicated? or am i looking at an expensive repair?

Blakey.
 
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Blakey

Blakey

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Hello Colin, :)

I was hoping you would reply! I didn't have long this evening to get under the bonnet, but I couldn't see an obvious leak. I guess best bet will be to get the sump tray off and check from underneath. Is it safe to drive in this condition?

Thanks matey,

Chris.
 

Cole@MBS

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Its wont do no harm Chris, i think we have all the 203 pipes in stock if you can get it to us!!

Your just have a loss of power and it might throw the engine light on Chris!!!!!
 
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Blakey

Blakey

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Thanks for the reassurance Colin, - and I'd love to come and see you and Dave again, but my time is precious at the mo.

I'll get the sump tray off tomorrow and find which pipe is split, and I've got a choice of 2 MB dealers in my area to get them from, so should have it sorted by the weekend.

I did a diagnostic, and no relevant codes showing. The oil level is still ok too.

Thanks again. :cool:
 
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Blakey

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OK, progress so far...

I picked up both intercooler pipes, item 30 (o/s) and 50 (n/s) and when I got down to replacing them, I found the o/s pipe was quite oily around the lower ferrule, and when I removed it, there was a small nick in the rubber. The replacement was a modified design with strengthening right where the nick was on the old one. So there was I thinking I'd cracked it, and I didn't bother fitting the n/s one.

However, on the test drive, the hissing noise under hard acceleration was reduced, but still there.

I'm going to do the n/s pipe tomorrow and hope that sorts it all out, but I am worried that the intercooler might be blocked with oil residues or have a hole in it. I couldn't see an obvious way to remove the intercooler, so if anyone can help with info I'd be grateful.

Listening with both windows open, the sound does appear to be coming from the n/s but I couldn't be sure. Of course, it's difficult to test as the hissing only happens under load.

Cheers for any help etc :confused::confused:
 
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Blakey

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OK, so I've done both intercooler hoses now, but I'm still getting a hissing noise when I floor the accelerator. There is another hose that links to the inlet manifold, but that appears to be fine.

Any ideas? Could I have a blocked intercooler, or a turbo that's overpressurising the inlet manifold? There does appear to be some residue in the intercooler and the old hoses.

Any advice welcomed.
 
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andy@pcd-ltd

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one thing that springs to mind is the cat could be blocked slightly does the car lack power at all.

Or the intercooler could have a split in it
 
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Blakey

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one thing that springs to mind is the cat could be blocked slightly does the car lack power at all.

There does seem to be a slight loss in power.

Or the intercooler could have a split in it

This was my initial thought, but I decided to replace the hoses first as presumably they are cheaper than the intercooler.
 
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andy@pcd-ltd

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It would be worth getting it stuck on the star machine and get the fault codes read.

The other thing would be to take out the intercooler and check that .

Can you hear the hissing noise when it is stationary and just revved up
 
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Blakey

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I have a diagnostic reader, not star but reads all codes, stored and pending. There are no codes coming up related to this.

I would like to get the intercooler out, that would seem to be the simplest thing to test next, only I can't see how to get it out other than removing the main radiator first. Ideas anyone? Malcolm, if you're out there, do you have a paper on this perhaps?

The hissing is only when really booting it, say accelerating hard up hill. I can hear it when I have both windows open. And if i'm not imagining it, seems to be less so than before i replaced the two intercooler hoses.
 
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andy@pcd-ltd

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Theeasiest way is to remove the front bumper and then remove the intercooler that way
 

turbopete

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i believe an intercooler for an early 203 is around £600
 

Alex Crow

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there are decent pattern ones available now, either ecp or gsf, can't remember at the moment.
 

Uncle Benz

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Have a close look at where the exhaust downpipe joins to the centre section. There is a spring clip that holds the two bits together. Any black soot there??
 

Alex Crow

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good ponit uncle, this could be a blocked cat issue rather than a leaking hose.
 
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Blakey

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Thank you gentlemen for all your replies.

Dealership price for an intercooler is £258 plus vat. They said they'd give me a good discount if I stock order it rather than next day. But further investigation and thoughts on how the car has been driving lately...

When I first looked at things I took off the air filter housing and If I remember correctly there was some evidence of soot near the turbo/precat connection.

I do recollect thinking there has been more exhaust noise in recent months.

I have seen posts about removing the precat altogether, and I presume a special spool piece needs to be fabricated to bridge the gap. Any ideas on the cost of an exchange precat or where I can get the spool piece from?

On a service I had done by MB when I first bought the car about 2 years ago, they suggested the precat might be partially blocked. I thought they were just inventing work do didn't do anything about it.

Thanks again for your help!

Chris.
 

jbond1978

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Chris, not trying to hijack the thread, but did you ever find out if the intercooler could be taken off without moving the main radiator? I believe I have the same problem as you on a W202.128 (C250TD), only MB has diagnosed mine as a leaky intercooler - so I'm going to change the intercooler this weekend and any tips or tricks would be greatly appreciated :)

Best regards, Jens
 

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