CAT C9 blowby issues...... any info?

A customer of mine has CAT D6R XW with a C9 in it. When the weather is warm outside it blows engine oil out the blow-by tube, sometimes a couple gallons a day. When the weather is cool, we have never had an issue with it. However, its been near 100 here for the past month so its been doing it alot lately. He had the local CAT dealer look at it and they say they fixed it. Their "fix" was to run the blowby tube under the radiator and down through the grill so it just blows the oil on the ground instead of into the belly pans. Needless to say he was unimpressed and called me but I'm kind of at a loss. Any ideas? I think I'm going to have him change oil brands next service and try that.

Thanks, Sean

COuple gal a day is a little excessive. The re route of the tube was cats fix for the plugging of the radiator under normal blowby. How many hours does this have on it? Where is it at?

Its got about 6,000 hours on it I believe and its in NW Missouri. Just north of St. Joe.