ripp6957

I just got an '00 Grand Cherokee Limited, 4.7,auto. The previous owner overheated it. He replaced the radiator, but only runs 5 mins or so and starts to heat up. The radiator is pressurized when it starts, so this is telling me I'm getting combustion pressure into the coolant right away- meaning head gasket or cracks, correct? No coolant leaks anywhere that I can see. Any hints on how to diagnose this? I'm thinking I'll check cyl. pressures to determine which side first. Am I too optimistic to hope for blown head gasket only, or should I anticipate cracked head/block right off the bat? I plan on pulling both heads no matter what. I only paid $1K for this and it's in great shape, so it's certainly worth saving! Thanks in advance for any help you can be. Mark the fireman

ol"blue

Welcome to CF. That's a good price even if you have to replace the engine.
I'd start by doing a compression test as you stated. That will at least show you if you're dealing with only on side, and which side to look at. Then you can pull the heads and check the condition of the gaskets, to see if that was the cause. Then take the heads in to have them checked and serviced before re-installing them if they're okay.
Google timing chain removal/installation on this engine, as there are special steps to follow.

*As the engine sits partially under the windshield/cowl on this vehicle, it may be easier for you to do the repair work if you removed the engine and did it on a stand. JMO

ripp6957

Dan, thanks for your reply. I hope I don't have to pull the motor, but I'll see once I get into it. mark

ol"blue

Okay, good luck Mark. Keep us posted.

ripp6957

Here's my update. I decided to pull my car trailer home, so I didn't have any issues using a tow dolly, thanks for all the info. She rode comfortably enclosed the whole trip.
Now my problem is pulling the motor. I found a good, used motor for $1400. But I cannot get the old one out! I feel like an idiot, because I'm asking this, but do you think the motor/trans is rusted together? I know I have all the bolts out, but I'm thinking the alignment pins on the block are rusted to the trans. Any ideas? I've soaked them with WD-40. The Jeep is from MI, but it's really not that rusty underneath. I count 6 bolt holes on the new motor, 4 that go thru the trans to the block and two thru the block to the trans (they were difficult to break free). I'm no certified 'real mechanic' but can usually figure things out, but this is kicking my a$$!
Any help would be greatly appriciated!
Mark the fireman

ol"blue

Did you remove the torque convertor bolts?

The following is the complete 4.7L engine removal steps from the '00 WJ FSM.


REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove the front fascia.
(3) Raise vehicle on hoist.
(4) Remove exhaust crossover pipe from exhaust
manifolds.
(5) Disconnect two ground straps from the lower
left hand side and one ground strap from the lower
right hand side of the engine.
(6) Disconnect crankshaft position sensor. (Fig. 4)
(7) Remove structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - REMOVAL).
(8) Remove starter. (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - REMOVAL).
(9) Remove rubber splash shield.
(10) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(11) Remove torque converter bolts.
(12) Remove transmission to engine mounting
bolts.
(13) Disconnect the engine block heater power
cable from the block heater.
(14) Lower vehicle.
(15) Remove throttle body resonator assembly and
inlet hose.
(16) Disconnect throttle and speed control cables.
(17) Disconnect tube from both the left and right
side crankcase breathers, then remove the breathers
(Fig. 5).
(18) Discharge A/C system (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - STANDARD
PROCEDURE).
(19) Remove radiator fan (Refer to 7 - COOLING/
ENGINE/RADIATOR FAN - REMOVAL) and accessory
drive belt (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - REMOVAL).
(20) Remove A/C compressor (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/A/C COMPRESSOR
- REMOVAL).
(21) Disconnect transmission oil cooler lines at the
radiator.
(22) Disconnect radiator lower hose at the thermostat
housing.
(23) Remove A/C condenser (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/A/C CONDENSER
- REMOVAL).
(24) Remove radiator (Refer to 7 - COOLING/ENGINE/
RADIATOR - REMOVAL).
(25) Remove generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - REMOVAL).
(26) Disconnect the two heater hoses from the timing
chain cover.
(27) Disconnect engine harness at the following
points :
† Intake air temperature (IAT) sensor (Fig. 6)
† Fuel Injectors
† Throttle Position (TPS) Switch
† Idle Air Control (IAC) Motor
† Engine Oil Pressure Switch
† Engine Coolant Temperature (ECT) Sensor
† Manifold absolute pressure (MAP) Sensor
† Camshaft Position (CMP) Sensor
† Coil Over Plugs
(28) Release fuel rail pressure (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - STANDARD PROCEDURE)
then disconnect the fuel supply quick connect
fitting at the fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/QUICK CONNECT FITTING -
STANDARD PROCEDURE).
(29) Remove power steering pump and position out
of the way.
(30) Disconnect ground straps from the left side of
the engine.
(31) Install Engine Lifting Fixture Special Tool
8347 (Fig. 7)following these steps.
† Holding the lifting fixture at a slight angle, slide
the large bore in the front plate over the hex portion
of the lifting stud.
† Position the two remaining fixture arms onto
the two lifting studs in the cylinder heads.
† Pull foward and upward on the lifting fixture so
that the lifting stud rest in the slotted area below the
large bore.
† Secure the lifting fixture to the three studs
using three 7/16 – 14 N/C locknuts.
† Make sure the lifting loop in the lifting fixture is
in the last hole (closest to the throttle body) to minimize
the angle of engine during removal.
(32) Disconnect body ground strap at the right side
cowl.
NOTE: It will be necessary to support the transmission
in order to remove the engine.
(33) Position a suitable jack under the transmission.
(34) Remove the engine mount through bolts.
(35) Raise engine slightly, then remove both left
and right side engine mounts from engine. (Refer to
9 - ENGINE/ENGINE MOUNTING/FRONT MOUNT
- REMOVAL).
(36) Remove engine from the vehicle.

*Hope this is helpful.

ripp6957

Thanks for the reply! Yes, I had gotten the torque converter bolts already. I was correct in that the alignment studs were rusted to the trans. I soaked them with WD 40 and a LOT of muscle got it to break free.
Mark the fireman

ol"blue

Glad to hear you got them separated Mark.

ripp6957

Here's an update- sorry it took so long. I triple checked that I had all the bolts out, so I used a BIG pry bar and got it to free up. Seems there was quite a bit of corrosion holding it together. So I pulled it out, swapped everything over and slid the 'new' engine in. Hmmm, the alignment pins aren't lining up... seems the old ones stayed in the trans (corroded in) and the newer engine had them in. So, out comes the motor again, since I can't get the pins out in the cramped space. I slide it in again, not noticing I have bent the spacer that goes between the block and transmission. Still won't line up, so I pull it out again (gets easier each time!), straighten the metal and slide it in again. I finished up the job and she runs good. So I proceeded with minor body repairs and paint just in time to load it BACK on the trailer for the trip to MI.
LESSONS LEARNED- check, check and check again before you put the engine back in, so you only have to do it once! Don't bend the metal spacer that goes between the block and trans! And the best lesson was that even tho I have NO experience with late model engines, it's not too bad if you have a good manual, some patience and common sense. I'm going to stick to my pre 1975 projects as much as possible from now on. This old dog has trouble learning new tricks! Thanks to all for your input and guidance.
Mark the fireman