Hello, I'm looking into buying a 2001 Grand cherokee. it has the 4.7L V8 in it. I don't know anything at all about this particular engine, (unlike the 4.0 I6, which I know inside and out) and wanted to know how many miles I can expect to get out of one, and what possible failure points are. truck has 145K on it right now.

Any info would be greatly appreciated. thanks,

-Rich

I think the cooling system is very sensitive so you would need to keep it at top notch condition.

2002 jeep cherokee
 

Its a 6cyl. Automatic.
When I put it in drive and pull out, it feels like I'm in second gear. If I manually put it in first it pulls out like it should, but shifts kinda hard into 2nd. Only has 63,000 miles on it. Could it be the selonid...

Okay Rich! The 4.7 is a "next generation" engine and has it's own set of rules. It needs proper maintenance to enjoy good health. Basically, it's an iron block with aluminum heads running overhead chain drive cams and individual spark coils on every plug. The bottom end has a "girdle" instead of individual bearing caps and the connecting rods are machined in one piece, then the caps are "broken off" so each one only fits itself. The camshafts run in aluminum bearings so oiling is essential and cooling is critical because of the different heat expansion between the iron and aluminum.

Having said all that, it's a good engine, IF TAKEN CARE OF!

Cold Weather Question
 

Hey guys! Just was wondering if y'all could give me a hand here. The last few days have been incredibly cold around my neck of the woods (-30 including wind chill last night), and it didn't seem to have too much of an impact on my Grand Cherokee until this morning. When I went to start my Jeep to go to work this morning the first turn of the key wouldn't get it to start and then it let out this loud, high pitched noise that sounded like it was coming from one of the air vents on the passenger side. Then I turned the key again and it finally turned over and started up, but the engine didn't quite sound right. I tried to take it around the block just to see if it would warm up and things would work themselves out, but as I started driving I noticed that diving didn't feel right, almost like a lack of power, and the was a slight rattling noise as I sped up a bit. I'm thinking it probably just had something to do with the oil and it being a lot thicker due to the cold and not getting into the engine quick enough, but I always assume worst case scenario (and I'm usually right), and I've only recently started to become a real man when it comes to vehicle knowledge, so I just wanted to get some input from you beautiful people to see if that's what y'all thought it was, or if there might be another issue I'm unaware of. Also, if you could offer any advice on steps I could take ahead of time so this won't be an issue next time, that would be appreciated! Thanks guys! (And gals!)

Get an engine block heater. Plug it in an hour or more before you leave. It preheats the oil and gets everything up to heat quicker. I've got a timer that I plug one of our Jeeps into that comes on 2 hoursish before it leaves in the morning.

Awesome I'll definitely have to get one of those. Any recommendations?

Kat's makes the best ones I've seen in my experience. They replace a soft plug in the side of the block and heat the coolant with a 110 volt line cord. They also make a battery wrap that keeps the battery warm. I've seen diesel trucks with both of these on them that started in the bitter cold without ether.

ALSO, once it starts, shift to neutral and allow the transmission to warm a little before requiring it to function. In neutral, fluid flows thru the cooler coils in the radiator and warms up, energizing the seals. I've done this ever since I got a governor pressure warning after a cold start at -15*F.

I know where you're coming from. It was -33*F here in Syracuse last night. I was out delivering Sunday newspapers, driving around with the window wide open! A diet soda on my console froze while I was driving! I had to stop several times to warm up the cabin and my gloves to avoid frostbite. It was brutal!! My 4.0 however, performed flawlessly.

Google "Kat's engine heaters". JMHO, but that high pitched scream was probably your heater blower fan complaining.

So maybe you could help me with something. I'm not quite sure how to explain it, but it almost feels like my brakes work normal, then they catch really well, then normal then hard again. I've tried looking it up on various sites, and all I have seen is change brakes, or rotors, but my rotors don't look pitted or warped. And ideas?

Glazing on the friction surfaces? When was the last time they were done?

How do you know they aren't warped? Removed and checked for runout?

I just got the wj 8 days ago. I noticed he issue and pulled the wheels off. I'm not sure what runout is, but the pads need to be replaced. I talked to a buddy of mine that said it could be a brake booster but I want to do a little research before I go buying parts. I'm new to the jeep scene and figured someone here may have had this issue.

Runout is when the rotor wobbles in&out as it rotates. It can be caused by being warped or having a missing lug nut or having crap under the mounting on the hub. Worn hub bearings can cause the same feel.

I've had my 2000 WJ for 5 years now and the brakes are something I've had constant problems with. When I first got it, the front calipers weren't working at all. When we tried to bleed them, we got no fluid pressure to them. After opening all 4 bleeders and pumping the brakes, they started working again and have been since then. I had a piston in one caliper seize up so I changed both calipers. I happened again so I changed both calipers AGAIN along with both hubs, rotors, mounting brackets, hoses, and ceramic pads. Now my ceramic pads squeak when not being used, but work fine when applied. I think I'm going back to semi-metallics. My brake booster is questionable. When I first bought the jeep, I had a vacuum leak when applying them hard but worked fine under normal braking. After a year or so, the leak seemed to seal itself. Lately when it's extremely cold, if I use them hard, the pedal goes lower then normal and if held at that point, fades a little. I'm loosing a little brake fluid when this happens with no visible leaks, so I'm assuming it's going into the engine thru the booster. IDK. The ABS system is crap! It works at it's leisure whenever it decides to or not. When tested, it works fine, but on the road it can't seem to make up it's mind. On ice or snow, sometimes the only way I can get it to stop is kick the trans into neutral. I've pulled the fuses on the system, but I keep getting strange error messages so I put them back in.

Every other system on the jeep works perfectly, but the brakes have always been a problem. Oh...Yeah. The A/C hasn't working since a week after I bought it. When recharged, it works for a week.

Oil pressure sensor question
 

I found out thru research that somewhere in the 2002-2003 model changeover, the oil pressure sender isn't an actual pressure sensor anymore but is a "slide switch" that only sends a 40 psi signal to the gauge. My question is; as long as the jeep has a gauge, will a sensor from an older model actually show REAL pressure?

Need Help Please, Stranded
 

4.7l 2000 Grand Cherokee, oil pressure dropped, got p1391 changed both CPS and CKS, oil pressure sensor, than big back fire and blew aprt throttle body cover, now get p0121, change TPS and even the ECM. It starts but wont idle and is VERY ROUGH. Any Ideas. Plugs on left look good, Right side a little fouled. could the right cam have jumped off timing.

just got a 2000 wj 6cyl 2wd 132000. no troubles, any advice for routine maint now?
 

this is my newest jeep, just looking for any advice on what i should think about doing to this truck, the good, bad and the ugly so to speak. thanks to all in advance!