Some advice on engine replacement / upgrade

[Far McKon]

Hey folks;

Erratic visitor, I read a lot more than I post.  The TL;DR is that in this past heatwave my poor 'ol MJ overheated. Turns out the radiator was clogged with slime, and only about 1/3 of it was 'flowing' and couldn't cool enough on a over-100 F. day.

 

My mechanic (that I trust pretty well) has strongly recommended a new engine. He cited a a re-manufactured engine at $3,500, for a total of $5,000 to $5,500 for engine, new radiator, install, etc.

 

If someone has a minute, I'd love some advice:

 

1): Does that cost pass the sniff tests ?

2):  Any other maintenance work that would be smart to loop into this? I don't have  A/C, would it save money / be smart to get an A/C while doing this?
C) In the worst case, if I can't get it repaired, what is a decent condition MJ with no engine (in Philly PA) worth to others?  $1,000?  $3,000 ? Nothing?

 

Trying to figure out what to do here. I'm open to other ideas or other advice on this if anyone has it.

 

(Not *my* engine. It's from another post. I put it here for reference if people want to suggest specific upgrades / fixes/ whatever, point-to things to do while doing the replacement, things like that.)

[Gjeep]

Not sure how many miles you have, but an overheat doesn't require a new engine unless you kept driving, and driving and driving. But there are things to redo and look at. How bad was the overheat, meaning approx how long were you in the red for? Redo/ get new all that is cooling related -- radiator, all hoses, thermostat, depending on mileage and how neglected new copper heater core (or at least flush it). Was the head gasket/ head effected. Personally, I'd swap all the cooling related mentioned above, do an oil change and drive it -- keeping an eye on the temp gauge. There's a good chance your engine is just fine. 

[Far McKon]

Ok, I'll think about that one.  Thx.
 

I drove it about 10 min overheated, to get home / off the highway, then parked it a day.  Then 2 nights later, I tried to limp it over to the mechanics (25 minute drive total). I drove 5 min at a time, then paused 10 to 20 to cool.  It stalled out and would not restart 1/2 way there, so I got a tow. 

 

The mechanic mentioned part of the problem is the temp sensor was 'dry /  in the "radiator muck"', so by the time it register too much heat, it was probably overheated a while.  He did offer to try to just do the radiator swap + new head gasket, but he was pretty sure I would be back to him in a month or two for a full engine swap.  Happy to get a 2nd opinion on that too.

 

In hindsight, it was taking too much of a risk. At the time, I considered doing a flatbed to the mechanic,  bit limping it over didn't seem crazy. :facepalm:

[Car Enthusiast]

My stroker rebuild cost less than 5k, but I did it myself.

[Pete M]

I've overheated my 88 to the nth degree more than once.  still works ok.  

[87MJTIM]

The 4.0 is a pretty resilient engine.

 

Do you have an open or closed cooling system?

 

If it were me, I would first have an engine flushed and repair/replace the radiator, water pump, and reservoir bottle and cap (if closed).

 

It sounds like your mechanic is recommending the above changes, anyway.

[Far McKon]

Not sure what 'open' or closed is here. When it overheated, there was a valve ( by 'coolant reservoir') that was bubbling over. Does that explain? 

[fiatslug87]

In ‘88 the 4.0L had a closed cooling system, no fill neck on the radiator, a plastic pressure bottle on passenger side firewall and no overflow tank, hence closed. People swap to open by usually adding a radiator that has a fill neck and an overflow bottle which is called open because it’s open to the environment. Snap a picture of your setup.

 

p.s. the pic you posted is an open system and it’s not a V6 as in your signature, it’s an inline 6.

[pizzaman09]

I have overheated an engine in a Mini to complete melted down destruction.  It took driving it without coolant for a few hours on a cold day.

 

The sounds of it, I bet you just lost a head gasket, though it is possible that there is  more damage like pistons scuffed.

[75sv1]

1): Does that cost pass the sniff tests ?

I'd say yes. Probably $3,500 for a rebuilt engine, and $1500-$200 for labor.

2):  Any other maintenance work that would be smart to loop into this? I don't have  A/C, would it save money / be smart to get an A/C while doing this?

A/C can wait. I'd think about a front seal for an auto trans. Possibly a Torque converter. 
C) In the worst case, if I can't get it repaired, what is a decent condition MJ with no engine (in Philly PA) worth to others?  $1,000?  $3,000 ? Nothing?

$$$ would depend on body condition. Rust Free, I'd say $2,000. Also would depend on the quality of the paint. Still, your looking for a buyer that sees spending money up front. So, 10% of the buyers. 

   I've also driven a Jeep XJ that 'overheated'. Ran fine afterwards. This depends on what amount of work you are capable of. I'd ask about milage, but some or a lot depends on how the engine was cared for. Doesn't sound good if the radiator fluid wasn't changed at intervals. Still, worth a shot. You are going to have to change the radiator and coolant anyways. Also, change to an open radiator system. Then see about a head gasket. 

[75sv1]

I did look at rebuilt 4.0L prices. Somewhere around $2,000 to $2,600. 

[Smokeyyank]

When I did a rebuild in my XJ I paid 2500 for everything including r&r. That was several years ago, but I had my 4.7HO rebuilt recently in my WJ and that was 5k with r&r, but it's a more expensive engine to work on. I think it's a little high price wise, but look online at some of the long blocks should get you an answer. Its not a crazy labor intense process. The 4.7 was an absolute B. As for needing a rebuild from overheat hard to say. I overheated my 88 drove home about 10ish minutes. I've been about 25k since then without issues. 4.0 can take some abuse. 

[ghetdjc320]

I also locked up a 4.0 from overheating once. Still ran fine once it cooled back down and I was able to repair the cooling system. The 4.0 is a stout little engine. I wouldn’t be concerned. Mechanics often like to scare people into purchases. As for the price, it may be a fair price for the swap, however, you’re not going to add 5k of value to your MJ. If you plan on keeping it for a long time and driving it, then maybe it’s worth it. Personally I’d just clean out the cooling system (by someone who has the proper equipment to chemically backflush the whole system under pressure/vacuum not just a drain and fill), do an oil change and run it. Your head gasket may also be just fine. 
Overheating is bad for any engine, but it’s not like the 4.0 is some sort of super tight tolerance racing engine. It’s more like an old tractor engine. 

[75sv1]

I'd replace the water pump, too. 

[Far McKon]

Thanks for all the info / feedback. Calling the shop today to sort out options / price on this.