random questions

[XWrench3]

so i have a few random questions, 1) on the 3.7l dropping valve seat thing, is there any rhyme or reason behind it, or is it just bad luck? i think from what i have read, that overheating can be a contributing factor. what about mileage? is a high mileage engine more or less likely to drop a seat? 2) i just replaced the O2 sensor in my KJ, i cleared the codes it had, so there is finally no more check engine light displayed. how long would it take for another code to trip the light if there is still another problem? sadly, i have never had a vehicle from the modern era that did not have a check engine light on.

 

[turblediesel]

I remember the days when a check engine light meant NO OIL, PARK IT!

I think overheating is probably the biggest reason for dropped valve seats and guides. Aluminum heads warp fast. Insufficient warmups can cause microcracks in alloy engine parts which eventually play "connect the dots(cracks)" releasing tension on fasteners and pressed parts.

 

[tommudd]

^^^ Yes overheating is main issue to dropped valves
If there is another issue it should trip the light right away