I am new here and buying a 99 Cherokee 4.0 tomorrow. When I checked it out, it seems really clean, 2 owner, 137K miles. I did notice the passenger side of the block, a sheen of an oil leak. Some was near the distributor, some a little further aft. No oil on the spark plug wires like in the photo. Someone here has a good pic of their passenger side oil leak and the answer that was given doesn't make sense (bad heater hose or PCV valve). There weren't too many responses so I'd like to check with the pros. Thanks

 

In that area I'd suspect the valve cover gasket. Cheap fix, and very common issue. If your heater hose is leaking oil then you'd have a huge problem lol. The PCV is on top of the valve cover.

 

If your spark plugs look good with no oil at the top it really can only be a couple other things if you think about it. My guess would be the oil filter adapter o rings or your oil pressure sending unit. Both are straightforward fixes but the adapter is a real pita. Mine used the biggest hex I've ever seen, still have it, I had to use a 6 ft breaker bar and it finally cracked loose. Good luck.

 

Really good input. I'm glad no one said head gasket. I'll see it tomorrow and hopefully will be the new owner. Do you know what size hex it was?Thanks guys!

 

I agree Oil Filter Adapter or valve cover gasket, both ar pretty easy, but its kinda hard to change the o-rings in the adapter because at the factory they put it on with loctite and its a torx bolt.

 

Will look when I get home but out of the 3 Cherokees I've owned they all had different bolts on that damned adapter.

 

I am completely new here and am blown away by how helpful and nice everyone has been. I'm a classic Goldwing owner (76') and have had great forum kindness on that website (www.ngwclub.com) from others, but I'll tell you. Your kindness is rivaling even theirs. I am very impressed here. As soon as I start learning I will help give back. I can promise you that!