jjmason.6

2000 C4 Cab. Problem started with a massive smoke plume out of both exhausts. Checking things out revealed intermix both ways, although very little coolant in oil when it was drained and allowed to separate. (Oil had just been changed 1000 miles prior).

Local Porsche shop suggested oil cooler replacement. That was replaced as well as the AOS (Air Oil Separator). The smoke problem was resolved as well as the coolant in the oil. Oil is still getting into the coolant somehow.

Car has always run fine and never overheated or showed a CEL. Everything I read says its a cracked head?

Seems odd that some of the issues were resolved but am still getting a one way mix. Is there another entry point that oil can be forced into the coolant but not vice versa? Seems that a cracked head would intermix both ways?

Dharn55

Do a search here, there are lots of threads on this including my intermix and fix. Did they test the oil cooler before they replaced it? They should have as this is an easy test and it is seldom the oil cooler that is the problem. Possibly an AOS, but not too likely.

Remove the plugs and tubes on #1 and #6 and look for cracks, you might see one.

Flat6 Innovations

THE mode of failure for 2000 model engines are cracked heads. We have 11 different 200 and 01 996s here now, all with cracked heads. We saved all but one of them, it was driven to death.

We are now seeing many, many more intermix related failures than anything else.

aviography

Jake,

How were the water pump impeller blades on these cars? Were any loosing material and being the sole contributor to this problem?

BTW, immensely enjoyed your spring time meet & greet session in Toronto.

Flat6 Innovations

Not all of them, 6 of them had bad water pumps or had just had the water pump changed in the year previous, following a pump failure. It sometimes takes the debris a while to find a capillary to block and create a localized hotspot that propagates into a crack that bridges the coolant and lubrication passages.

The 2000 model cars can fail without having a bad water pump. We have some very good clues as to why this is because the cracks always come at two different places within the cylinder head and have the same dynamics behind them. A 2000 model year engine does NOT have to overheat to crack a head!

Here is a link to the photo album for this week's patient
https://www.facebook.com/media/set/?...4914693&type=3

Nice meeting you in Toronto as well. I really should put more of these meet and greet sessions together as I travel North America to instruct my Porsche M96 Engine Mechanical Schools :-)