Is this an obvious exhaust leak?

[DaniTD]

Tired of the backfiring and my clothes having the same odor as the exhaust fumes I started to inspect the exhaust system and found this on the joint between the exhaust manifold and the exhaust pipe (it's a M40):




Is this an obvious exhaust leak? Shouldn't it be sooty? Why White? The engine does not drinks coolant. Could be this making the engine make the ticking noise on the motorway at 3500rpm and the blurbing sound under the dash at low rpm on high load?

Thank you!

[xavier]

Mine was making the ticking noise and blowing from where the exhaust manifold meets the exhaust down pipe(m20). It turned out there were two leak points. One where the manifold meets the head and one as mentioned where the manifold meets the exhaust. The manifold to head leak was caused by the manifold warping slightly. Apparently this is not uncommon. So perhaps check there. You can take manifold out and get it machined and fit new seals. i had the old dodgy 3 stud early m20 manifold. I bought a 2nd hand exhaust manifold for the later 325i. I got it all machined nice and flush(about $120.00 Australian). Then I fitted it with new seals and it solved the ticking and blowing. I hope this helps. Also check for snapped studs between the head and exhaust manifold. These studs can sometimes snap and cause a leak.