HELP! 4.0L overheated, cracked block, now I need a new motor. - JeepForum.com
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Unread 09-18-2012, 04:36 PM   #1
TEXAS_TJ
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HELP! 4.0L overheated, cracked block, now I need a new motor.

I have a 2004 4.0L with 80,000 miles on it and the radiator just failed and the motor over-heated. It got hot enough to crack the block. It failed the block test @ Firestone and now they can't even give it the Texas State inspection until a new engined is installed. Firestone quoted $5,800 including tax and labor for a rebuilt motor with a 3 year 100,000 mile warranty. (+ new hoses, radiator, water pump, etc.) Basically everything done and out the door for $5,800. Good, fair, or bad price???

Seeking your advice on the rebuilt motor above vs. dropping in a stroker. Not sure what other parts would be needed with the stroker.

I just moved to Leander, TX a month ago. Anyone around me that can help? Recommend a cheaper mechanic, etc?

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Unread 09-18-2012, 04:43 PM   #2
Jeepson33s
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What is a "block test"?

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Unread 09-18-2012, 04:45 PM   #3
Agent620
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First mistake was taking it to Firestone. Take it to an independent shop. Find a good mechanic you can trust. Not some chain shop. I used JB weld to fix a cracked block on a CJ5.
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Unread 09-18-2012, 05:01 PM   #4
ChadH
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Originally Posted by Jeepson33s View Post
What is a "block test"?

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A "block test," otherwise called an engine block test is a pressure test used to determine if there is a leak in the cooling system. It will not necessarly pinpoint where the leak is, but in normal circumstances if it shows positive for a leak it will usually be in the engine (head, gasket, or block) somewhere as if it was in the radiator, heater core, or hoses you would physicall see it.


TEXAS_TJ, I would recomend a replacement engine. But I would also recomend having a jeep dealer do it. It may cost a bit more but it will be warrantied better, and if there are any issues during that warranty period there is a better chance of it being fixed at no cost to you. If you have an aftermarket place fix it, and there is a problem that related to the install or some other component that is not part of the engine specifically, they may not honor the warranty. Typically those warranties at aftermarket places are only for the part itself, and not relating to the installation. (EX - if they replace the engine and in the process screw up...say, the transmission and the transmission does down in 10K miles they might not replace the transmission at no cost to you.
I would also recomend a direct engine replacement unless you want to deal with having to upgrade other parts in the future. The drivetrain components are designed to withstand loads from the output abilities of that engine. If you drop in a stroker with more power, you are now overloading the rest of the components of the vehicle and may break something in the future depending on how hard you are on it.
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Unread 09-18-2012, 05:22 PM   #5
shatteredsoul
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Thats the craziest thing I have ever heard, it seems unlikely to crack a cast 4.0 block just by over-heating. How far did you drive it or let it run after it got hot? Other than an obvious failure of the block I dont know of any other way to test it other than tear it down and magnaflux it for cracks. What if it was simply a freeze plug?

Also $5,800 is ridiculous even for Firestone, even if the block is actually bad why not but a stock replacement or a drop in stroker yourself and save the rest of the money? Shoot you should be able to put in a Hemi for that price!
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Unread 09-18-2012, 05:27 PM   #6
01TJ-Bob
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Quote:
Originally Posted by Agent620 View Post
First mistake was taking it to Firestone. Take it to an independent shop. Find a good mechanic you can trust. Not some chain shop. I used JB weld to fix a cracked block on a CJ5.
I have to agree, If your going to leave it MAKE them use a Jasper engine. The price they quoted you with the extra parts isn't terrible but what company do the use for there reman motors. Insist on a Jasper engine they by far are the best builders out there.
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Unread 09-18-2012, 05:35 PM   #7
TEXAS_TJ
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Thanks for the input everyone. I'm not a gear head, I have only done simple repairs to my previous 1990 Commanche and this 2004 TJ. The Jeep was only driven a few miles when it overheated. I was very suprised too when they said it failed the block test. It was only leaking from the radiator, so if I replaced that, would it still run good enough to trade it in at a dealer? Haha. I've only lived here a month and I haven't had the need for a mechanic yet, and I'm tight on time to get this Jeep up and running.
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Unread 09-18-2012, 05:54 PM   #8
vtwinjunkie
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HAHA....a block test. I would want more info on this test. perhaps a blown head gasket maybe. I dont know it sounds sketchy to me.
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Unread 09-18-2012, 05:59 PM   #9
sduncan
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Well the first thing I'd do is get it the hell away from Firestone....next I'd find an independent shop who knows a little something about jeeps and get another opinion.

I'd be willing to bet your block is not cracked....
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Unread 09-18-2012, 05:59 PM   #10
shatteredsoul
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I would bet my TJ that the block is ok, I would spend the money and replace the following and KEEP THE JEEP....

Radiator
Water pump
Thermostat
Radiator hoses
Heater hoses

Flush and back flush the heater core with a garden hose, after all of that you should be able to get another 100,000 on your engine. Everything listed is easily done with a few tools in your driveway in a day and will save you tons of $$$$. You need to invest in a factory service manual set for you Jeep, I just picked up a complete set for $46 shipped off fleabay.
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Unread 09-18-2012, 06:27 PM   #11
gmiller0737
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1 Get a 2nd Opinion, If you are new to the Area ask some one for a reference or start here http://autorepair.iatn.net
Have the 2nd shop do a "Block Test" Most Likely Cause of a Failed Block test is Cylinder head or Gasket Issues It may be possible to have the head reworked & Magnafluxed (To check for cracks) Resurfacing may be needed if wharped beyond specs. If a Replacement engine is needed Jasper Engines have a Decent Track record
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Unread 09-18-2012, 06:51 PM   #12
karik
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cracked block...? no way.

my hobby is dirt track racing, we overhear engines all the time, beat the snot out of them. overheating WILL NOT CRACK A BLOCK.

it might warp an aluminum head, unlikely to warp a cast iron head.

something else will go long before cast iron cracks.

how long did you drive it dry with no steam coming out?

worst case a new head and gasket. best case the head gasket blew out. what is the oil like? if it looks creamy, head gasket.

steer clear of a stop that automatically recommends a new engine.
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Unread 09-19-2012, 10:17 AM   #13
TEXAS_TJ
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Quote:
Originally Posted by karik View Post
cracked block...? no way.

my hobby is dirt track racing, we overhear engines all the time, beat the snot out of them. overheating WILL NOT CRACK A BLOCK.

it might warp an aluminum head, unlikely to warp a cast iron head.

something else will go long before cast iron cracks.

how long did you drive it dry with no steam coming out?

worst case a new head and gasket. best case the head gasket blew out. what is the oil like? if it looks creamy, head gasket.

steer clear of a stop that automatically recommends a new engine.

2 weeks ago I replaced the radiator, fan clutch, water pump, thermostat and hoses. It has ran fine the past 2 weeks (at 50+ miles per day) with no over heating and temp gauge has been working just fine and never exceeded210 deg.

We drove it about 10 miles earlier that day (was fine), then again for about 3miles. At the end of that 3 mile haul I noticed the smell, then check the temp gauge and it was maxed out. (my wife was driving and didn't notice it) nor did we see any steam, nor smell anything in the cab.

It was raining at the time, so I couldn't really tell if there was a leak, so I let it cool and went back out when the rain died down and I opened the radiator and added a bunch of water, which confirmed there was a leak as I could see it coming out the back of the radiator at the bottom where the metal "grips" the plastic tank.

I filled the radiator up and also a couple gallons of spare water and headed home (about 12 miles away). I thought If I was lucky, we'd make it the whole way, worst case, I'd have to stop and let it cool and add water. The leak wasn't minimal, but it wasn't horrible bad.

We made it about 10 miles when the gauge started to go over 210 deg. We stopped immediately and let it cool, then filled teh radiator back up and headed home, and we made the remaining 2 miles with no issues and not over 210 deg.

The next day I filled the radiator back up and drove it 3-4 miles to Firestone. It drove fine and the temp guage just barely went above 210 as we pulled into the paring lot.

I had company in-town and we had stuff planned, so I just figured I'd have them replace the radiator and I'd just loose out my warranty through AutoZone on it. I just didn't have time to deal with it.

They said they'd have to run the block test since it over-heated, and they said it failed and that the motor was shot.

They said I could put in a warranty claim with AutoZone and say that the radiator failed, which caused the engine to over-heat, which caused the block to crack, but they said the manufacturer would probably say there was an air pocket in the system when I installed it, which caused the crack. Oviously that's not the case, as it was fine for 2 weeks after the install, but not sure how I prove that to the radiator manufacturer/AutoZone.
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Unread 09-19-2012, 10:31 AM   #14
1998tjsport
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Originally Posted by TEXAS_TJ View Post
2 weeks ago I replaced the radiator, fan clutch, water pump, thermostat and hoses. It has ran fine the past 2 weeks (at 50+ miles per day) with no over heating and temp gauge has been working just fine and never exceeded210 deg.

We drove it about 10 miles earlier that day (was fine), then again for about 3miles. At the end of that 3 mile haul I noticed the smell, then check the temp gauge and it was maxed out. (my wife was driving and didn't notice it) nor did we see any steam, nor smell anything in the cab.

It was raining at the time, so I couldn't really tell if there was a leak, so I let it cool and went back out when the rain died down and I opened the radiator and added a bunch of water, which confirmed there was a leak as I could see it coming out the back of the radiator at the bottom where the metal "grips" the plastic tank.

I filled the radiator up and also a couple gallons of spare water and headed home (about 12 miles away). I thought If I was lucky, we'd make it the whole way, worst case, I'd have to stop and let it cool and add water. The leak wasn't minimal, but it wasn't horrible bad.

We made it about 10 miles when the gauge started to go over 210 deg. We stopped immediately and let it cool, then filled teh radiator back up and headed home, and we made the remaining 2 miles with no issues and not over 210 deg.

The next day I filled the radiator back up and drove it 3-4 miles to Firestone. It drove fine and the temp guage just barely went above 210 as we pulled into the paring lot.

I had company in-town and we had stuff planned, so I just figured I'd have them replace the radiator and I'd just loose out my warranty through AutoZone on it. I just didn't have time to deal with it.

They said they'd have to run the block test since it over-heated, and they said it failed and that the motor was shot.

They said I could put in a warranty claim with AutoZone and say that the radiator failed, which caused the engine to over-heat, which caused the block to crack, but they said the manufacturer would probably say there was an air pocket in the system when I installed it, which caused the crack. Oviously that's not the case, as it was fine for 2 weeks after the install, but not sure how I prove that to the radiator manufacturer/AutoZone.
This all sounds really sketchy to me. Just do as some one else said and replace the radiator and go from there. 6k to replace a 4.0? Assuming that it is an honest 8 hour job at $100 an hour for labor thats about $800. SO the new engine is 5k? Bring the radiator to auto zone show them the crack, they will give you a new one. Put it in and drive the thing, its a 4.0 you can fix them with a hammer and some sticks they are so strong and simple lol. Don't let some tires shop jerk you for half the value of your Jeep. Maybe someone on here local to you can take a look and help you out.....
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Unread 09-19-2012, 10:51 AM   #15
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I'm with 98tjsport. The 4.0 is super strong block. It's not a diesel block, but it's still way overbuilt. Firestone is trying to fleece you ($5800 with no upgrades sounds like robbery to me).

What does your oil look like? Does it look like dark to black cooking oil or a milkshake? Pull your oil fill cap on the top of the engine and run your finger around the inside. Any frothy residue? (These symptoms would mean the coolant was leaking into the oil.)

Are you getting white smoke out of your tailpipe? You should see something coming out of your tailpipe if the block is cracked and the coolant is leaking into a cylinder.

Is there any coolant in the engine bay? It should be an orange liquid (green if someone put the wrong, older stuff in), and it probably dries to a white powder or otherwise looks like a white hard-water stain when dry. Any of that in the engine bay? If there is, can you trace where it's leaking from?

Have you checked your radiator cap? When you pull it off, there's a rubber gasket in the cap that should be smooth and clean. If the rubber is cracked at all, toss it and get a new one. It should be an 18psi cap, and they're cheap (Summit has them for $5).

Also, all of these symptoms can be caused by other things failing, like the head gasket, which everyone keeps bringing up for a reason. You've got a 2004, so you should have an 0331/TUPY head, which is unlikely to crack (but would likely go before the engine).

Again, take it to someone else. Firestone's estimate is bad, and I would be surprised if they didn't misdiagnose your problem. The block is the last thing to check. At 80,000 miles, your 4.0 is just getting broken in.
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