Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
I doubt blanking the EGR is enough. A careful look at my failed flaps shows the underlying problem to be the very small plastic bearings that locate the top of the flap spindle. The bearing is barely 2mm ID, and what happens is that over time it elongates sideways. This is going to happen due to vectored manifold pressure variations hammering the flaps hundreds of time a second, when partly open. The spindle is then free to displace sideways, jamming the flap into the side of the port and eventually fatiguing welds until they break.
So build-up of oil/carbon gum isn't the main problem. It's soft and gooey enough to get pushed out of the way. My flaps and inlet tracts showed this happening. It was metal flap to metal port contact that was the issue.
Having an abrasive mix of carbon and oil will shorten the plastic bearing life, but I am pretty sure it will fail anyway due to being so pitifully underengineered. If so a blanked EGR is at best going to delay failure some.
The good news is that once the flaps are removed and EGR blanked and mapped out, a whole heap of potential and recurrent problems are fixed for good. It is *the* mod that should be done to every 1.9 CF4 as soon as you get it, as important as cam belt service but you only need to do this once.
PS I had 2 flaps break off - 1 at 75,000, 1 at 78,000 mls - causing head and valve damage. Ned at AL said he's seen it as low as 30k mls. I'd guess it's about the same level of risk as a cam belt, anything past about 50k is gambling against odds that get steadily worse. There's probably a bell-curve distribution, with a peak around 90-100k and a few cars making it to 120 or 130k, from reports on these forums.
Last edited by halftone; 22-06-16 at 13:53.