Replace the head or complete engine overhaul

[tj_Joe]

So,

Here is my dilemma. I have a 98 TJ with 200k on it. I cannot have my jeep down long as it is my daily driver. I have coolant in my oil and did a compression test. 120 on a few most have 90. Blown head gasket from what I can tell, but I am worried once I get it off I see more damage. So I basically have a couple of options.

Option 1.

Buy new head and install as I cannot afford to wait until the machine shop gets done with it. This would entail replacing all gaskets as well as doing a new rear main seal and oil pan gasket as I do have a leak from there as well. I priced out all the parts and it came to about 650.00 for this.

Option 2.

Buy a reman engine, pull the old engine and drop in the new engine. Hopefully I can get this done in a three day weekend I have this weekend. engine has a three year warranty. I realize Autozone engines are not the best, however this is my option at the moment. Basically this would probably give me at least another 100k on the Jeep as it already has 200k on it.

Any opinions would be greatly appreciated.

 

[Chris]

At least another 100k on a remanufactured engine? What world are you living in?

These things regularly make it to 500k miles. A guy on this forum who sold his had 600k on the original engine when he sold it, only major things he had to do was rebuild the transmission every 200k miles.

100k is not even broken in for a 4.0. Maintained properly, they will last well past 200k miles.

That being said though, what is the cost of the reman engine?

If it's not too much more than the cost of the head, I would consider the whole new engine, only because it may not be much more.

 

[tj_Joe]

At least another 100k on a remanufactured engine? What world are you living in?

These things regularly make it to 500k miles. A guy on this forum who sold his had 600k on the original engine when he sold it, only major things he had to do was rebuild the transmission every 200k miles.

100k is not even broken in for a 4.0. Maintained properly, they will last well past 200k miles.

That being said though, what is the cost of the reman engine?

If it's not too much more than the cost of the head, I would consider the whole new engine, only because it may not be much more.

Chris,

I am thinking worst case since I am getting it from AutoZone. Cost of the head is 450, including gaskets head bolts and everything total is about 700 after getting my core charge back.

Total for the reman engine is 1650, they have one in stock. Including gaskets is about 1725. it is 1k more. I am just thinking longevity.

I am also thinking wase of replacing the Rear Main seal and Oil Pan Gasket. How many hors for just the head, RMS and OPG, vs replacing the engine?

I really do not want to open it up then realize everything is crap once I pull the head. The reman head is returnable, and I doubt they will sell the reman engine in just a day, so that option is available. I just don't know if replacing the head and gasket will also fix my lack of power while accelerating in 4th gear, or is that just a Jeep thing; all I have to compare it to is my JL.

 

[Brian83]

If you think its just a blown head gasket just pull the head, slap on a new gasket and go on for another 200K miles.

 

[tj_Joe]

If you think its just a blown head gasket just pull the head, slap on a new gasket and go on for another 200K miles.

The PO I am finding was not the best at maintaining this vehicle. a lot of gasket sealant to stop problems and such. Already replaced the cooling system, Front track arm, sway bar disconnects steering stabilizer, front and rear diffs, steering gear, sway bar links and much more.

I am afraid it just isn't replacing the gasket. Head needs to go to a machinists, hence buying one instead of waiting for the machinist to take care of it.

 

[Brian83]

you can buy one worked over from Clegg Engines in Utah that has been ported, polished, with oversize valves for $850 if thats something that your looking for.

 

[tj_Joe]

you can buy one worked over from Clegg Engines in Utah that has been ported, polished, with oversize valves for $850 if thats something that your looking for.

That was the debate. Just replace the head with a new once since I cant have this down for long. Or just buy a reman engine and do a swap since this engine is in unknown condition.

 

[billiebob]

So,

Here is my dilemma. I have a 98 TJ with 200k on it. I cannot have my jeep down long as it is my daily driver. I have coolant in my oil and did a compression test. 120 on a few most have 90. Blown head gasket from what I can tell, but I am worried once I get it off I see more damage. So I basically have a couple of options.

Option 1.

Buy new head and install as I cannot afford to wait until the machine shop gets done with it. This would entail replacing all gaskets as well as doing a new rear main seal and oil pan gasket as I do have a leak from there as well. I priced out all the parts and it came to about 650.00 for this.

Option 2.

Buy a reman engine, pull the old engine and drop in the new engine. Hopefully I can get this done in a three day weekend I have this weekend. engine has a three year warranty. I realize Autozone engines are not the best, however this is my option at the moment. Basically this would probably give me at least another 100k on the Jeep as it already has 200k on it.

Any opinions would be greatly appreciated.

I've done a few rebuilds, never been happy with the results.

April 2017 I bought a remanufactured engine with a 7 year warranty. Now with 60K miles on it it is still running like new. Tight with no oil leaks. I bought it thru S and J Engines in Spokane. I guarantee they will have a long block in stock. They have a huge warehouse and ship worldwide.

That remanufactured 4.0L long block was $1800. All you have to do is bolt on the accessories and drop it in.

 

[Chris]

Chris,

I am thinking worst case since I am getting it from AutoZone. Cost of the head is 450, including gaskets head bolts and everything total is about 700 after getting my core charge back.

Total for the reman engine is 1650, they have one in stock. Including gaskets is about 1725. it is 1k more. I am just thinking longevity.

I am also thinking wase of replacing the Rear Main seal and Oil Pan Gasket. How many hors for just the head, RMS and OPG, vs replacing the engine?

I really do not want to open it up then realize everything is crap once I pull the head. The reman head is returnable, and I doubt they will sell the reman engine in just a day, so that option is available. I just don't know if replacing the head and gasket will also fix my lack of power while accelerating in 4th gear, or is that just a Jeep thing; all I have to compare it to is my JL.

Honestly, given that the reman engine is only 1k more, I would probably go that route only because you're already in there doing the work, and at least you get that peace of mind of knowing the engine is entirely new. Like I said, 4.0s last forever, but 1k isn't that much more in the grand scheme of things, so if it were me, I'd probably just replace the whole engine.

If you put in a new engine, I believe it should come with a new rear main seal and oil pan gasket, no?

I figure the head is probably 6-10 hours, plus maybe 2-4 hours for the RMS, and another 2 hours for the oil pan gasket (depending on how slow you work). That's about the same amount of time as putting in a new engine honestly.

 

[tj_Joe]

Honestly, given that the reman engine is only 1k more, I would probably go that route only because you're already in there doing the work, and at least you get that peace of mind of knowing the engine is entirely new. Like I said, 4.0s last forever, but 1k isn't that much more in the grand scheme of things, so if it were me, I'd probably just replace the whole engine.

If you put in a new engine, I believe it should come with a new rear main seal and oil pan gasket, no?

I figure the head is probably 6-10 hours, plus maybe 2-4 hours for the RMS, and another 2 hours for the oil pan gasket (depending on how slow you work). That's about the same amount of time as putting in a new engine honestly.

Chris,

The Reman does come with Gaskets, I just wanted to replace them with FELPRO is all. I work a little slow because I will be doing this on my own and it will be my first time doing any of these. Giving myself three days to accomplish it all starting Friday this week. Probably going to go with the reman engine but need to get it by the boss first.

Thanks, and ill let you know how it goes as I may be in need of advice as this goes on. been reading the forum and watching videos to soak up as much knowledge as possible on all of this.

 

[Chris]

Chris,

The Reman does come with Gaskets, I just wanted to replace them with FELPRO is all. I work a little slow because I will be doing this on my own and it will be my first time doing any of these. Giving myself three days to accomplish it all starting Friday this week. Probably going to go with the reman engine but need to get it by the boss first.

Thanks, and ill let you know how it goes as I may be in need of advice as this goes on. been reading the forum and watching videos to soak up as much knowledge as possible on all of this.

Oh yes, good call on the FelPro gaskets, those are the way to go.

I definitely think you can finish it in a weekend. I don't know if yours is a manual or an auto, but if it's a manual, you'd be silly not to put in a new clutch while you're in there as well (unless it is new already).

I replaced the 4.0 in my XJ about 8 years ago with a reman 4.0. I did it in a weekend. I had the help from a friend which was great. It wasn't that bad in all honesty.

 

[Goatman]

Coolant is hell on bearings. If it (water in oil) just happened I might roll the dice on just a new head/gasket. If there has been antifreeze mixing with the oil for a while I would hate to go through all the work and expense to then find out the bearings are failing in 10k miles. With the cost of a whole re-man (only) $1k more and comes with a warentee it seems like an easy call to me.

 

[S.McArthur]

Honestly, if the funds are there, I'd replace the engine, I haven't pulled an engine in a long time, but it doesn't seem as difficult as some other (cramped engine bay) vehicles.
Use the old engine as a learning tool or sell to recoup a few $$, unless there a core charge. As Goatman said, coolant in the lower end + 200K miles may cause some long term issues. Cost v Benefit $1k + labor cost now or later...I can't spend your money, good luck on your choice.

 

[tj_Joe]

Coolant is hell on bearings. If it (water in oil) just happened I might roll the dice on just a new head/gasket. If there has been antifreeze mixing with the oil for a while I would hate to go through all the work and expense to then find out the bearings are failing in 10k miles. With the cost of a whole re-man (only) $1k more and comes with a warentee it seems like an easy call to me.

I decide to

Honestly, if the funds are there, I'd replace the engine, I haven't pulled an engine in a long time, but it doesn't seem as difficult as some other (cramped engine bay) vehicles.
Use the old engine as a learning tool or sell to recoup a few $$, unless there a core charge. As Goatman said, coolant in the lower end + 200K miles may cause some long term issues. Cost v Benefit $1k + labor cost now or later...I can't spend your money, good luck on your choice.

I appreciate everyone's replies. Since both are available locally, I am going to try to pull the head tonight time permitting. Or tomorrow morning finishing up. Ill upload a picture of the lower end to see what you guys think. Both the head and engine I can get same day so I am not too stressed about that. I realize the time spent my be more pulling the head first, but the boss said I have spent too much money already in the last 6 months on the Jeep unless absolutely necessary. So I need to prove it is required or its just a head replacement with new gaskets, the RMS and oil pan gasket until the engine gives out completely.

I want to thank you all and will hopefully have more to show for it in a day.

Thanks

 

[tj_Joe]

So I got a late start tonight. Attaching picture where I ended the night. Spent half my time trying to get electrical clips undone that have been together since 98. I did brakes a few brittle tubes. Will post pics as well in hopes you guys could help.

Also, do I need a special tool to take off that little thing on the fuel injection?

 

[Airjunky]

I just did an engine overhaul after a spun rod bearing. I bought an overhaul kit from Partsology.com.....gaskets, rings, bearings & pistons. Plus a new pushrod. Then took it, the dismantled block, crank, cam, head & associated parts to American Machine in Spokane. They did all the machining, short block & head assembly for about $800.
The engine has about 3k miles on it & runs great so far.

A couple issues that occur to me that you may have. There are 2 different 4.0 liter heads. Apparently one is prone to cracking & not easily repaired. Plus if your engine was overheated, both the head & block may need to be machined flat again.

There is a tool to disassemble the fuel lines.

 

[JEEPCJTJ]

You have mentioned a lot of stuff on the Jeep you've already replaced and the boss's thoughts about money. The best way to make sure that was money well spent is to pull the whole engine and replace it. It may cost a little more but then you have way less to worry about needing fixed ($$$) in the future.

 

[Goatman]

Even if you are thinking just a head gasket you kinda have to pull the crank caps to get a look at the bearings. 200K miles and to leave the old bearings and rings when you know they are more than likely damaged by the coolant intrusion makes no sense to me. You will be into it for the same, or possibly more hours than if you replaced the engine. And what happens when you find a bad bearing in the bottom end? I would do my best to consider the difference between knowing you and the Boss have a 'new' engine and a warentee versus a new head gasket and a hope. Smart money (to me) is fix it right and be done. In my youth I would likely try and hope for a head gasket and done, but as I get (got) old I realize the value of knowing the next time I turn the key nothing will be punching a hole through the block.

 

[tj_Joe]

Ok,

so I know everyone’s suggestion is to replace the engine. At this time I think it is just the head, RMS and oil pan gasket.

going to get a donor block soon and rebuild it myself and when I get the time I will use the new head I am putting it now. Not including some of the parts obviously. I just want some pride to say I did it I think as well as I can slowely get the money past the boss who says this is a money pit.

all that said, since this is open, I’m thinking replace the feeeze plugs. Not looking in great shape. Let me know what you guys think from the pictures.

 

[tj_Joe]

Even if you are thinking just a head gasket you kinda have to pull the crank caps to get a look at the bearings. 200K miles and to leave the old bearings and rings when you know they are more than likely damaged by the coolant intrusion makes no sense to me. You will be into it for the same, or possibly more hours than if you replaced the engine. And what happens when you find a bad bearing in the bottom end? I would do my best to consider the difference between knowing you and the Boss have a 'new' engine and a warentee versus a new head gasket and a hope. Smart money (to me) is fix it right and be done. In my youth I would likely try and hope for a head gasket and done, but as I get (got) old I realize the value of knowing the next time I turn the key nothing will be punching a hole through the block.

Goatman,

I get what your saying. Not just replacing the gasket replacing the whole head since I don’t have time to take my head to a machinist. Quick weekend job. completely agree with replacing the engine. Think I’m going to find a donor 4.0 and rebuild it as I can take a little bit of time with it and still use the head I just bought minus push rods and such.