Just had to have this replaced on my 10 reg 18500 mile 2.0 cr 110 Yeti. I know what the EGR is and does (I hope) but didn't know about the cooler. I assume it cools the exhaust gas before entering the inlet manifold, but how is the cooling achieved, and what would have made it fail?

Just Curious.

Chris

It's a simple heat exchanger (not sure if gas-to-air to gas-to-water in this case). They can corrode or get filled with deposits, due to condensation of exhaust gas nasties such as aqueous acids and oily residues/soot. I can't think of another common failure mode, unless there's a possibility of fatigue induced by vibration.

I wonder what state the EGR valve itself was in?

This diagram might be of interest; not VAG specific but gives a good idea of the systems associated with a modern diesel.

Oh EGR leaks have been an issue for VAG on and off for a while now, so not an uncommon repair job.

TP

Does the inlet manifold on the modern common rail diesel engines suffer from the build up of sludge from the stuff in the exhaust overflow combining with the crankcase breather outlet mixing together, or has there been a fix developed since the earlier days of the PD engine?

Chris