[My 98 Durango SLT 4X4 5.2 Magnum is blowing out huge clouds of smoke after 20 mins or more at freeway speeds when I let off the accelerator and the accelerate again huge clouds of smoke come out at the back for a minute or two then stops smoking. I have tiny oily splatter all over my back window as well. It starts and runs fine and has plenty of horse-power I just replaced the cat converter, PCV valve and grommet, tranny pan gasket changed air filter. What could this be I don't see alot of oil on the engine top, front or sides that are visible and it doesn't seem to be coming out the exhaust.

 

Welcome!

Have you checked the level of your oil? Have you looked at the new PCV valve to see if that is filled with oil? Are you sure that it is the correct valve? I've seen cases where someone would install the wrong PCV valve and it created some issues. I'd also pull out each spark plug and look at them to see if they are "wet" with oil.

 

I have 99 Durango that uses alot of oil so I had the compression checked and that was good. Went ahead and replaced the valve seals. Did not help. Did the PCV replacment. No change. Started reading on the internet that there is an issue with the gasget on the bottom of the fi intake (plenium gasket). A couple companies have a fix for this problem. If you stick something up inside the tail pipe it should be wet. The problem is the plenium is steel and the intake aluminum. Both have different thermal expansion rates.

 

Looked up my past info. a company called Hughes makes a fix for this issue.

 

Thanks I'll check that out and post the results

 

A simple way of seeing if the bottom of the plenium is leaking is to remove the air intake from the throttle body, rotate the throttle body plates and look inside. If you see the bottom is wet, then the gasket is leaking. If it is dry, it is not leaking.

 

What did you find out?