oil leak in dodge 3.0

[wvcab]

2000 dodge caravan, with 3.0 v6, 270k,  the motor runs strong, gets great gas mileage (18 city/21 hiway), but is using a quart every 700 miles.

it seems to be blowing it out the cam seals, and the front crank seal.

i have replaced pcv valve, and the breather hose that runs from the valve cover to the air cleaner seems to have a lot of pressure built up, and the air filter seems to get saturated with oil on the lower half....

if you dont have the dip stick in ( a driver broke it off, and it took a couple days to find one) it blows oil all over.

should it have pressure like that?

[taxpyer]

Should be no preasure, sounds like the other end of the system is plugged. PCV valve should be sucked closed at an idle.

2000 dodge caravan, with 3.0 v6, 270k,  the motor runs strong, gets great gas mileage (18 city/21 hiway), but is using a quart every 700 miles.

it seems to be blowing it out the cam seals, and the front crank seal.

i have replaced pcv valve, and the breather hose that runs from the valve cover to the air cleaner seems to have a lot of pressure built up, and the air filter seems to get saturated with oil on the lower half....

if you dont have the dip stick in ( a driver broke it off, and it took a couple days to find one) it blows oil all over.

should it have pressure like that?

[wayne petty]

3.0 overhead cam motors....  

has that motor overheated recently?/  lost the cooling fan...waterpump...  tubes behind the  water pump that come out above the transmission???/

what happens...   when those motors overheat... the pistons expand far enough that the clearance between the piston and cylinder wall is removed...  and the heat tries to expand it farther... this distorts the piston and collapses it... it can also score the sides of the pistons and the carbon build up will lock the rings in place allowing excess blowby...


but before all this...

lets test the PCV system....    i have forgotten right this second... but pulling the pcv valve from the valve cover...    with the engine idling   place your finger over the end... do you get suction...   then unplug the hose from the pcv valve...  does the engine stall?   is there significant air flow through the hose...    there have on other cars... where the PCV passages in the intake or throttle bodies have gotten clogged and blocked with carbon build up.....  

i have cleaned some restricted PCV valves by having somebody work the throttle  keeping the engine at about 2500 to 3000 rpms.. and spraying brake cleaner into the end of the PCV ....   the brake cleaner will sometimes dissolve the blockage.. and let it flow through the motor without stalling the motor and hydraulic locking it with the liquid flow from the spray cleaner...

a short section of speedometer cable core can also be wound through the pcv hose as it will go around corners...


testing the pcv continues...

after verifying the flow on the pcv side..

on the breather side... At Idle ,  block it with your thumb... or palm of your hand...  in 10 seconds.. pull away... it should make a small POP noise as the air rushes in and the pressure equalize...

there used to be a little round tool from rimac tools... a PCV system tester... about the size of an eisenhower dollar but 5/8 thick.. (if somebody runs across one of these at a swap meet.. please buy it for me... i have wanted one of my own for decades..)  


in these motors... all the moving parts are in the heads...  the block only has the crank , rods and pistons..   unless mopar has stuck a balance shaft in the block...    when i worked at the engine rebuilder  one of the owners friends was a chrysler tech... made extra money rebuilding these...

he would take the intake and heads off... then lift the engine block out..   drop it back in that way...  then assemble in place...   he was good at it...

if you have to take it apart... be sure to examine the coolant pipes in the back of the water pump... if they are rusty at all....  you might want to replace them....  chrysler dealers... and Dorman have them..

[wvcab]

pcv valve, screws directly to the intake, and has a hose connecting to the valve cover, and there is vacumm on the hose from the valve.

the pvc hose connects to the valve cover closest to the radiator.

motor has not overheated in the last 125k that i am aware of, i did replace the water pump last may though, and the passages looked ok.

the rear valve cover has a hose 1/2" dia., that runs to the air box, this hose has the pressure on it, with the engine running and the hose disconnected at the airbox, you place your thumb over the end of the hose and the pressure builds quite rapidly.

i wish i had a pressure guage so i could  measure the amount...

the exhaust is clean, no puff at take off, so it is not burning the oil, just blowing it out at the seals.

[wayne petty]

aims back at the PCV system...

take the  PCV out.  verify the passage is not clogged... verify the valve is not clogged or the internal spring is not broken...



if there is not enough flow...  the PCV system cannot handle the blow by...


check the breather filter... where ever that goes....  there should NOT be any pressure build up in the crank case....  

either the PCV can handle the blow by at idle.. or  excess pressure will be vented out the breather...    usually back into the inlet duct... or air filter box...  so the breather is getting only filtered air...

check your PM...