td4 black smoke under pressure

Hi, i am a newbie but have lurked for some time hope the more experienced on this site may be able to help me.
When my td4 try's to get past 40 mph there is a bang then black smoke starts billowing from the exhaust, if i leave it to cool down then it is fine to drive around town exhaust gasses are clear the engine sounds normal.

also the oil gauge reads at half way so seems normal, i have had it to landy specialist because it had an amount of oil like substance in the cooling system but he didnt think it was oil and suggested cleaning the system which i did and it still seems clear, he also didnt think it was the head.

Hope someone can help as i am at a loss.

Check the intercooler hoses - top front of the engine - I bet you have a small spilt somewhere or they are soft and collapsing under load when hot.

Here was mine - piping banging black smoke engine lights on no power all for a small split that eventually got bigger!

Thanks for the reply i checked the inter cooler pipes the lower pipe had a small rub mark were it sits on a screw so i taped around it but the top pipe seems OK.

i hope it is something small like this please keep the comments coming

Have you as stated above got somebody to rev the car as you look at the hoses to make sure they are not collapsing.

I went down the taping route - it doesn't work. Are the hoses coated in a fine most of oil? Mine were the new ones are not!

Thanks for the reply yes they had a fine coat of oil on them before i cleaned them and no i have not tried revving the engine and checking the pipes but good point i will try that tomorrow and let you know the outcome. thanks

craig5056 said:

Thanks for the reply yes they had a fine coat of oil on them before i cleaned them and no i have not tried revving the engine and checking the pipes but good point i will try that tomorrow and let you know the outcome. thanks

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I think your hoses ave become porous and either leaking or have softened sufficiently for them to collapse under load. Mine were like this - I bought a coupe of new ones off eBay ( may not be best quality but seem ok) they were much stiffer and the problem was solved - they remain dry - no oil coating. I think the 2 hoses cost about £25

Thanks Angeloc i will look into getting new hoses and let you know the outcome

Thanks for all the help it turned out to be the lower pipe working its was on and off when put under pressure, could only buy a new one from the dealer or ebay so will wait a day or two and get one at half the price from ebay.

craig5056 said:

Thanks for all the help it turned out to be the lower pipe working its was on and off when put under pressure, could only buy a new one from the dealer or ebay so will wait a day or two and get one at half the price from ebay.

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Wahay a result - hope it sorts it