Jeep Cherokee 1999 Electronic Service Manual page 1033

9 - 16 2.5L ENGINE
DESCRI PT I ON AN D OPERAT I ON (Cont inue d)
BUILD DA TE CODE
Th e en gin e Bu ild Da t e Code is loca t ed on a
m a ch in ed su r fa ce on t h e r igh t side of t h e cylin der
block bet ween t h e No.3 a n d No.4 cylin der s (F ig. 2).
Fig. 2 Build Date Code Location
Th e digit s of t h e code iden t ify:
• 1st Digit —Th e yea r (8 = 1998).
• 2n d & 3r d Digit s—Th e m on t h (01 - 12).
• 4t h & 5t h Digit s—Th e en gin e t ype/fu el syst em /
com pr ession r a t io (H X = A 2.5 lit er (150 CID) 9.1:1
com pr ession r a t io en gin e wit h a m u lt i-poin t fu el
in ject ion syst em ).
• 6t h & 7t h Digit s—Th e da y of en gin e bu ild (01 -
31).
F OR EXAMP LE: Code * 801H X23 * iden t ifies a
2.5 lit er (150 CID) en gin e wit h a m u lt i-poin t fu el
in ject ion syst em , 9.1:1 com pr ession r a t io a n d bu ilt on
J a n u a r y 23, 1998.
LUBRICA TION SYSTEM
A gea r —t ype posit ive
m ou n t ed a t t h e u n der side of t h e block opposit e t h e
No. 4 m a in bea r in g. Th e pu m p dr a ws oil t h r ou gh t h e
scr een a n d in let t u be fr om t h e su m p a t t h e r ea r of
t h e oil pa n . Th e oil is dr iven bet ween t h e dr ive a n d
idler gea r s a n d pu m p body, t h en for ced t h r ou gh t h e
ou t let t o t h e block. An oil ga ller y in t h e block ch a n -
n els t h e oil t o t h e in let side of t h e fu ll flow oil filt er.
Aft er pa ssin g t h r ou gh t h e filt er elem en t , t h e oil
pa sses fr om t h e cen t er ou t let of t h e filt er t h r ou gh a n
oil ga ller y t h a t ch a n n els t h e oil u p t o t h e m a in ga l-
ler y wh ich ext en ds t h e en t ir e len gt h of t h e block.
Ga ller ies ext en d down wa r d fr om t h e m a in oil ga l-
ler y t o t h e u pper sh ell of ea ch m a in bea r in g. Th e
cr a n ksh a ft is dr illed in t er n a lly t o pa ss oil fr om t h e
m a in bea r in g jou r n a ls (except n u m ber 4 m a in bea r-
in g jou r n a l) t o t h e con n ect in g r od jou r n a ls. E a ch con -
n ect in g r od bea r in g ca p h a s a sm a ll squ ir t h ole, oil
pa sses t h r ou gh t h e squ ir t h ole a n d is t h r own off a s
t h e r od r ot a t es. Th is oil t h r owoff lu br ica t es t h e ca m -
sh a ft lobes, dist r ibu t or dr ive gea r, cylin der wa lls, a n d
pist on pin s.
Th e h ydr a u lic va lve t a ppet s r eceive oil dir ect ly
fr om t h e m a in oil ga ller y. Oil is pr ovided t o t h e ca m -
sh a ft bea r in g t h r ou gh ga ller ies. Th e fr on t ca m sh a ft
bea r in g jou r n a l pa sses oil t h r ou gh t h e ca m sh a ft
spr ocket t o t h e t im in g ch a in . Oil dr a in s ba ck t o t h e
oil pa n u n der t h e n u m ber on e m a in bea r in g ca p.
Th e oil su pply for t h e r ocker a r m s a n d br idged
pivot a ssem blies is pr ovided by t h e h ydr a u lic va lve
t a ppet s wh ich pa ss oil t h r ou gh h ollow pu sh r ods t o a
h ole in t h e cor r espon din g r ocker a r m . Oil fr om t h e
r ocker a r m lu br ica t es t h e va lve t r a in com pon en t s,
t h en pa sses down t h r ou gh t h e pu sh r od gu ide h oles
in t h e cylin der h ea d pa st t h e va lve t a ppet a r ea , a n d
r et u r n s t o t h e oil pa n .
X J
displa cem en t pu m p is