jpryorx2

hey guys new to the page but i have a problem and need some help as i know nothing about jeeps. my mom has a 2000 cherokee with the 4.0 she blew a head gasket and overheated the engine AAA towed it to some noname shop where the guy had it for over a month to put on a brand new head. he also replaced the intake saying it was cracked,replaced the oil pump saying the pressure was low, and installed used push rods and rockers for who know why and charged her $1800. when she finally picked it up it runs like crap. the guy then said that it ran great for about a half hour then started running rough but he could rebuild the engine for her if she wanted. she actuallt listened to me and took it home then had it towed into a dealer to check it out. they said the number 4 exhaust valve isn"t opening and thats why it's running so bad.they didn't go any further then to pull the valve cover and do a compression check but said they would assume it was a bad cam.and she still has low oil pressure i now have to drive 4 hours to go look at it for her.shes had a rental car for over a month now so i'm heading to her place in the morning to check it out. my questions are

1.does anyone think that with new valve springs the pushrod could of crushed or bent since it would be pushing more resistance?

2.could it just be a collasped lifter?

3. can the lifter be removed without pulling the head so i can see the cam lobe?

4.if it's a bad cam does it make sence that it would run great for a half hour then just all the sudden round off a lobe? i know they wear out but i've never heard of one being that noticeable that quick.

like i said i have to drive 4 hours to even look at it and i will be extremly limited on time while i'm there so i'm hoping for a easy fix. sorry this is so long and thanks in advance for any input
jason

98 JeepJeep

remove the VC...maybe he didnt tighten a Rocker up all the way......but even with a Dead lifter you wont loose operation of a cylinder.....however the Head has to come off to replace the lifters........FYI for 1800 you could have almost got a Remanufactured engine with a warranty......

linuxrick

Sounds like that place is just throwing parts at it to see if the problem goes away. After becoming overheatd, that could have caused the 2000's head(infamous 0331 casting crack) to become bad. But overheating might have also fried the lower bearings, which might be why she still has low oil pressure. Does low oil pressure only show up after the half hour of running?

The place I bought my 2000 did the same thing trying to fix it for me, put a new oil pump, checked head for cracks, replaced oil sensor, then I got fed up and told them give me my $$ back. They settled and gave me 1/3 of my cash back so I took it and got a remanufactured motor and put it in myself.

jpryorx2

he did say the head was cracked after he got 3 used heads that were all bad she bought a new/remaned one from auto zone and took it to him. she had it done at some shop in holly i will find out the name once i get down there today.she threatened to sue him today and now he says he'll refund all the labor if she signs a paper saying she won't sue him.rigth there tells me he knows he screwed up. i guess as of now i'm going to plan on replaceing all the lifters,pushrods and maybee the rockers this weekend and use some thick oil and pray it get better.i guess at idle it has about 10 psi and when driving it goes up to 20 psi. no it doesn't run good for a half hour he said it ran good for the first half hour after doing the head and then went south. now it runs like crap even from a cold start.

jason

jpryorx2

i just talked to my mom the shop wasn't in holly she took it to friendly auto service at 9 and van dyke in warren just a heads up for anyone in the detroit area of where to avoid.

98 JeepJeep

quit wasting your time on that motor.......call advance auto and see if you can get a re-man SHORT block since you already have the new head...they use SPARTAN for there engines and they come with a 36MONTH warranty.... when i priced out a CHEVY 350 it was only 1,400 so a I-6 should be less.

jpryorx2

i'd love to but she doesn't have the money to replace the engine right now.thats why i'm looking for a band aid fix to last her atleast for a few months while we either look for a used one on craigslist or till she has the money for a reman.i would rather swap in a know good engine then to keep driving down there on a fishing trip. which is basicly what i'm doing today. her engine has 180k on it so i see no use in replacing a cam if thats what is wrong with it. i guess my first step is check the pushrod for the nonworking valve then compare the lift on that one to another exhaust valve. if i'm thinking right that will tell me if it's a bad cam

jason

98 JeepJeep

correct....they make dial guages to measure Rocker travel....However If the dealer never took off the VC how do they know a Exhaust valve isnt opening? if that was the case the Engine would Airlock.....and shut off...you probally have a dead cylinder caused by burnt rings.......do a compression test...

jpryorx2

ok heres an update now that i made the trip i pulled the valve cover and the rockers for the no4 cylinder. no bent pushrods and i think the cam is worn some because the exhaust valve push rod isn't coming up quite as much but the valve is still opening i guess just not all the way. compression is at 110-115 in all cylinders. being dumb i didn't scan the codes till after i pulled it all apart but it is pulling up a cylinder 4 misfire if i remember right the number was a p0304. it is idleing rough but a dead cylinder would cause that so now i need to track down this problem. any advice

98 JeepJeep

check the plug.......you may have a bad coil rail.....

Throttle Jockey

if you have good compression on all six then you dont have a dead cylinder. i had this happen to me before. i had a fly-by-night shop do some work and they said the same thing "dead cylinder". turns out they did not get the push rod in the lifter and the spark plug was mashed. double check everything. make sure all the basics are correct before you condem it.

98 JeepJeep

he said it has a Mis fire...for what ever reason the cylinder isnt combusting its dead.....

Throttle Jockey

if it has compression then it should, ya know? efi fuel system so it's getting fuel. if it's not getting spark to that cylinder then no fire. three things to run. fuel spark and compression. two outta three, only lacking spark. or could be injector not fueling.

98 JeepJeep

I feel like this saying is incomplete...fuel,spark,compression and correct timing....then it should run.......

Throttle Jockey

agreed. correct timing gives you compression.