Motor question...

1992 // auto // 4.0l h.o. // np231 // 4 door

my motor is running well at 207,000, with ok to good fuel mileage (14-17mpgs) and good oil pressure (25 at idle, 45-50 whist driving).

It uses oil to the tune of a quart every 500-1000 miles.

Its only two cylinders that seem to be letting oil into the combustion chamber according to my spark plug crystal ball.

What would you say my gamplan should be? .

I don't want a stroker. Not doing it.

I don't know that I need to pay for a ATK short block, but honestly I have the cash to "do the right thing" for it right now.

Would you have a shop you trust pull the head and pan off and just check the general condition, and then slap it all back to together with any combo of bearings, rings and head/valve guides, that it might need?

This is my DD. It's been nothing but reliable so far, with no overheating issues to speak of and I want to treat it right.

Maybe some of you wouldn't do a thing? Can you tell me your experience as to why? I'd sure like to not have the drive-thru and start up smoke that I'm experiencing, but it's not a SUPER big deal to me unless it's a clear sign of needing TLC.

with 207,000 miles it sounds like it is in decent shape. Does it pass emissions? If yes, I would wait until it smokes constantly. A long block would be a good fix if you want to put the 2-3K into an 21 year old vehicle. 1 qt every 500-1000 miles is not bad, i've seen much newer cars use more.

I haven't researched this since the late Eighties (1980s, not 1880s), but SAE standard for acceptable oil consumption was one quart per 500 miles MAX.

Personally, I would drive it until something lets go. While waiting for that to happen, pick up a low mileage late 4.0 and have it ready for a quick swap.

There is no reason the 4.0 won't give you over 300k miles IF MAINTAINED PROPERLY.

pokeyxj said:

with 207,000 miles it sounds like it is in decent shape. Does it pass emissions? If yes, I would wait until it smokes constantly. A long block would be a good fix if you want to put the 2-3K into an 21 year old vehicle. 1 qt every 500-1000 miles is not bad, i've seen much newer cars use more.

Click to expand...

Yeah it's passed smog 3 times since i owned it. Most recently in Oct.

I had the same problem you described, and I replaced the valve stem seals on the two cylinders that had oil fouled plugs. It idles like a new engine now with 289,000 miles on it. Took all of 2 hours the first time, and a new $18 tool, $3 for the rope and about $20 for a full set of valve stem seals. And I replaced the leaking valve cover with a new permanent gasket.

I was shocked at how easy it is to do. It was my first time doing them.

since you mentioned throwing caution at the wind, get the head redone and have them peak at the cylinders while at it, at that mileage a head job would never hurt any, it may up your mpg by 2-3... and if you haven't replaced the valve cover gasket, its a better win~ plus it may tell you more as to what direction to go...

I bought a 1994 4.0 XJ from a friend. It burned oil like a frieght train when it idled. I never kept track of how much oil it burned because it was so much. Thought motor was on its last leg, but a leak down test confirmed that it is pretty tight, only major long block issue is two leaking intake valves.

Had the intake/exhaust manifold off to fix a crack in the exhaust manifold an noticed oil all over the exhaust valve stems. Pulled the valve cover and replaced all 12 valve seals.

Burns almost no oil anymore, the difference is amazing.

I would get the head done, maybe P&P, valve job, decked and anything else that needs to be done. Maybe run the MP .043" headgasket.

I'd do a leakdown test. This could be someting as simple as valve seals. Been there and done that. Easy.

Thanks for the input so far. Good to know about the valve seal replacement. Didnt realize how simple it was. I'll have to do a leakdown test soon and see what i find.