1HZ/1HDT/1HDFT Owners: reroute your valve cover breather. Here’s why.

[gifu]

This 1HDFT motor has 100k miles (mas o menos). The factory oil breather (off the top of the valve cover) is plumbed into the intake manifold.
20 years of sending fumes into the intake results in this mess.

 

[Dork]

Mine looked even worse than that with only 120k. I think the EGR was to blame for most of it, but maybe made stickier with the oily air. EGR gone and breather hanging open to frame now.

 

[roscoFJ73]

Ive never seen that in a 1HZ and I have had several high klm air intakes in my shed over the years. I have one there now that did 143000klms before the engine spun a bearing and its as clean as a whistle.
These are probably JDMs that spent half their running time sitting in heavy traffic smouldering away

 

[GTSSportCoupe]

Yeah, it's primarily the EGR that does that. The PCV on it's own just leaves an oily film everywhere (like what you'll find in your intake system before the EGR inlet).

 

[gifu]

My last engine had no EGR and looked as bad. Just say’n.
At the very least putting a oil catch can in the system would help. I prefer to vent mine to atmosphere.