...And then

[Saurian]

Sorry to keep pestering you all, but this forum is really great. Everyone's very helpful in answering each other's questions, and I do have a lot of them... I learned about engines on an '84 Reliant, so my knowledge of jeeps is still growing...

My question:

What precisely is the difference between a 4.0 I6 high output, and a 4.0 I6? The HO is in my friend's '95 Cherokee Sport, and the regular is in my '00... Does it affect horsepower, fuel economy, what? The engines look really quite similar, short of his having a distributor, and a lot more little tubes and wires creeping around. What makes an engine high output?

Off the topic, the aforementioned '95 jeep just goes to prove that these things die hard. His mom drove it from Southfield, about 10 miles on the freeway, with no coolant, and a hole the size of a baseball in the radiator. The air cleaner box melted, as did the radiator, the upper hose, and the block at the 3rd cylinder. The temp gauge totally blew out, and the engine was totally seized. She cooked it. And after a new VERY used block and radiator (and hoses obviously), with 114K of city driving on it's original parts, it's driving just grand, on and off road... Aaah, the power of Jeep!

 

[Saurian]

And does the I-6 have a PCV VALVE per se? I can see the little thingadoos on top that seep oil and tube off elsewhere, but I'm asking in the context of "...And it looks like your PCV valve needs replacing, sir, it's recommended every blahdeblah miles..." Because they don't look like proper old-school PCV valves, although I could be wrong of course... :wink:

 

[Bounty__Hunter]

The '95 and '00 both have the 4.0L HO, even though they don't advertise the HO anymore. It meant about 20 more HP over the older 4.0L, don't remember the year of the switch.

The newer jeeps like your '95 have CCV instead of PCV. It stands for Closed Crankcase Ventilation. It should have a hose in the valve cover that connects to the airbox, then a smaller vacuum hose from the valve cover to the intake manifold. The vacuum hose to the intake manifold should have a small pinhole somewhere inline, in a small plastic connector. This often plugs up and causes the oil seepage you mentioned and oil in the air filter. Clean it out with a straightened paper clip.

 

[Saurian]

Ok, good to know that they're the same engine in that respect, and that I do NOT need to be replacing the "PCV" every 12000 miles or so... I'd heard about the CCV system before, but was not sure if that's what I had. I wonder how much they'd charge me to replace a non-existent part... :?

 

[dingus]

they switched from the non-HO motor to the HO in 92. i beleive the difference is in the cylinder head.