V6 - Hole in valve cover mystery

[DeadTom]

I have a 2003 Ranger XLT 4WD with the 4.0L V6
It is well cared for even though it is a daily commuter. Today on my way home smoke started pouring out from under the hood and I could smell it was oil. The oil was puking out of a hole that is on the passenger side valve cover and is at the firewall side. This hole looks to be about 2" long and it runs along a seam or casting joint.
does anyone know how this happened or what could have caused this hole to develop. And when I put a new valve cover back on is there something that I should be aware of?
Does anyone have a schematic of this engine?
Thank you all ahead of time,
DT

 

[rags]

Sorry to say but it sounds like your rear timing chain idler pully went south letting the chain go slack and the chain wore a hole in the cover.

The engine or transmission has to be removed to repair the damage.

 

[BRUTUS_T_HOG]

rags... that makes no sense at all. timing CHAINS are on the front of the engine not the firewall side. and it would NOT reach the valve cover at all

deadtom. pics please

 

[rags]

sorry but on the sohc 4.0 the passenger side timing chain is driven off the rear of the crank shaft and the drivers side is driven off the front

Been there ---- Done that

 

[DeadTom]

Rags,
Thanks for the quick response, the wear pattern in the valve cover looks consistent with what you stated above. The engine has been running very well and I had no warning that the chain had stretched that much. And what a funky setup to have the timing chains at opposite ends of the engine for each bank of cylinders.
I will try to get some pictures tomorrow as it is dark and snowing and I am just happy to have made it home with my broken down truck.
DT

 

[BRUTUS_T_HOG]

aaaahh now i see. didn't realize we were talking about a sohc. sorry. but seriously that sounds like an awful design

 

[DeadTom]

aaaahh now i see. didn't realize we were talking about a sohc. sorry. but seriously that sounds like an awful design

Brutus,
Agreed, it does seem like a POS design but with one overhead cam it is understandable to want to split timing chains into two different locations (front and back) otherwise the timing chains/spockets both on the front end of the engine would make it rather deep and prone to more flex along the cam shafts. Ahhh the joys of vehicle ownership.......
DT

 

[03ranger4x4]

yeah, as stated above, im sure theres a reason they set it up like that. ugh i just hope that never happens to my truck, i have an 03 xlt aswell.

 

[BRUTUS_T_HOG]

im sure there is a reason GM designed the 4.3l v6 the way they did... oh wait.. that was just a half assed v8 chop to save money.

the same probably applies here.

i see a lot of sohc and dohc V engines with the 2 chains both on the front with their own guides and it works fine.