Opened up my swapped motor and found...

Nothing! I'm in disbelief. I took out my motor a few days ago to swap in a fresh rebuilt one, and figured I'd open up this can of sardines and see what 160k looks like.

Background:
I bought the jeep with about 150 on it with a "blown head gasket" says the PO. Picked the whole thing up for $750. It hadn't been started on 9 months. The body and interior were mint, so I figured even if I had to blow 2 grand on a motor, I'd still have a really nice jeep in the end. Got home, did a [lot of] compression test(s). All cylinders checked out fine according to the gauge. Couldn't do a leak down test so, but I was feeling adventurous and though I'd try and turn it over. Threw on a jump box, it started right up no problem. Water pump inlet tube was leaking like Niagra Falls and was completely rusted away. Took off the water pump, and found the impeller blades sitting inside the block. Coolant was not liquid, but sludge. Replaced all cooling system components minus the heater core, flushed it about a billion times, and ran it like that for a year. Best $750 I've spent in my life.

Then the rust started catching up inside the engine again. The coolant was slowly turning to sludge and building up inside the block, heater core, rad, and head. I had to flush it about once a month just to keep it from overheating. Put together a brand new rebuild. New crank, new cam, the works.

I figured I'd at least find SOMETHING cool when I took this motor apart. A (non-speculated) blown head gasket, cracked head, gunky valve stems, mega worn out cylinder walls, anything. To my amazement the internals look pristine, considering the mileage on the parts. Seems like all it needs is a good hydrochloric acid bath and a rebuild kit and it would be golden again. Lots of red coolant buildup, that's it.

Let me know if you guys can tell me anything else about it from the pics.

No blown head gasket. At least I know my tests were telling the truth.


Underside. No crack between valves or cooling passages. No burned valves or crap builtup on the stems.


Cylinder walls. No huge lip or noticeable funnel shape. Factory crosshatches. This really threw me for a loop, the walls are smooth as glass and pistons clean as can be.



Ghettoass freeze plug fix. This happened leaving work at 8pm one night. Started her up and coolant was pissing everywhere. NO store in the area had standard 2" plugs, so rtv and this retarded invention were the only fix. Still leaked afterwards as well...


You can see the red coolant plague everywhere


Cylinder 6


Cylinder 5


Cylinder 4


Cylinder 3


Cylinder 2


Cylinder 1


I know there's a lot of guys here MUCH more knowledgable in engines than me, let me know what you think. I'll get pics of the cam etc tomorrow.

In cylinder number one on the intake valve looks like some red coolant of yours. Also looks like something was knocking around in there making those gray/tan marks on the bottom right. A

Also it looks like you were running very rich...

I am no expert by all means.. just an observation

I thought number one looked a little suspicious too, but the gasket looked ok all around the cylinder. What makes you say rich? The black inside isn't soot that was just the color of the metal. Although the intake valves on numbers 2 and 6 are darker than the rest. I dunno what the tan-ish marks are either??

#2 and #6 look like you may have a little oil getting by the intake guide and seal. Look through the #2 and #6 intake ports at the valve stems to see if you have more deposits than the other intake valves have. This is not a big deal, but the guides should be checked since it is apart.

The marks in #1 may be caused by detonation. Notice that exhaust valve is a different color than the others and looks like it has been running hot. The exhaust valves need to close completly and seat properly to transfer their heat to the casting and coolant. A hot exhaust valve sticking open is a common cause of detonation. Check for a weak spring or a bent exhaust valve stem. You can do a quick check of the valve seat by inverting the head to level and pouring a thin liquid on the chamber and see if any leaks through and which valve.

Why are you useing red coolant? The 4.0 engines all used the traditional green stuff. The usual cause of gelled coolant is mixing of two different types of coolant. I would clean it all out again with a good radiator flush and put the green stuff in there.

Great advice until:

MoFo said:

Why are you useing red coolant? The 4.0 engines all used the traditional green stuff. The usual cause of gelled coolant is mixing of two different types of coolant. I would clean it all out again with a good radiator flush and put the green stuff in there.

Click to expand...

That is what coolant looks like when there is rust in the system, it also helps to grow a red algae, hard to get rid of. I am willing to be he put Green in there. Also, red will not stain a motor like that.

I bet that thing looked like my old mj the first time I flushed it. It had the color and consistance ot tomato soup. Same as you, flushed the hell out of it, but 6 months later it came back.

Overall, the engine mighty healthy for its age and miles. Cross-hatch still on the walls? Inconceivable! That being said, the coolant system is infected by whatever happened to it and I am thinking the only way you can cure it (It is deseased) is to boil out the block, head, heater core, radiator and replace all of the hoses and the pump. Anything that has come into contact with the coolant is a source of reinfection of the system. Unfortunately, Aluminium cannot be boiled in an acid bath, it disolves... So, new parts there. Fortunatly, those are inexpensive parts.

From the pics, I would have the bores mic'd and if they are as good as they look, put standard parts back in it after the machine shop has cleaned out the major players. If you do decide to bore, then it is time to stroke as well! The guides will need to be checked, but they can be knurled once instead of replacing them. Less expensive, almost as good. Wish I was close, I'd help out!

The carbon build up on the head is, for all intents and purposes, non-existent. I have never seen a head that clean from a high mileage 4.0.

Best $750 anyone ever spent...

BTW, my opinions based on 4+ decades of engine building. Just sayin...

So what we have here is a very good example of why you need to use distilled water in the cooling system. Steam distilled water is as close to pure as you can get. No nasty little microbes and certainly no minerals to clog up the works.

RO (Reverse Osmosis) will work but why spend the extra cash? But under NO CIRCUMSTANCES use DI (Deinoized) water. DI is an entirely unnatural material and will do everything it can to re-inize itself which is why it is used in the semi-conductor industry (and others) as a cleaner. DI will disolve your metallic parts. In truth, if you drink the stuff, it will kill you due to metal loss. For instance, Calcium is a metal... Like your bones and teeth?

You put the red stuff in it instead of the green ?. Interesting, the FSM says nothing by Etheline glycol. I wanted to change over to some of that fancy new synthetic but was warned against it and strongly suggested to stick with the green stuff and distilled water. I just did a drain and refill on my 98 two weekends ago, was serviced by a friend/mechanic two summers ago, he refilled it also with the red stuff after a flush, when I drained it it was pretty nasty. Ran a few cycles of tap water drain, refill, drain run, refill run drain then did the last refill with 4 gallons of distilled, let that run out and refilled with 100% prestone green, checked the blend with a tester and brought it to full fill and 50/50, seems to be running much better now. Also cleaned all the backwash out of the over flow bottle, man that was nasty, had to use a sock on a stick, the leftover red stuff was like grease or bad jello.

If you were having a problem with fungal build up, could you run a vinegar mix for a while to help clean the system and kill any bugs?

Maybe I was a little misleading earlier. NO red coolant was ever used. I'm willing to bet the PO put straight water in it after having overheating issues and not wanting to spend bread on coolant. All I ever used since I owned it, was pre-mixed Peak green. This is by far the dirtiest cooling system I've ever seen. On the new motor, I'm going to bypass the heater core completely until I have some time to replace it.

As for the head, unless it doesn't need any machine work I'm going to core it and get a reman and go from there. For $250 it's just not worth the hassle when it can be replaced so cheap.

Oh, noticed something strange today. The head gasket is a Victor Reinz... Now this is getting more interesting.

The red waxy deposits sure looks like dexcool waste to me

ehall said:

The red waxy deposits sure looks like dexcool waste to me

Click to expand...

1st gen dexcool had some real problems with algae contamination. And you are right, it really does.

Yikes. If I was ever caught putting dexcool in a vehicle I'd expect to be shot.

Semi-on topic, anyone have some good links or reads to what coolant SHOULD be used? The best kind? On my previous jeep I used Volvo OEM coolant because it was convenient at the time and I had about 6 gallons. It was a blue color, looked really cool. That cooling system stayed clean as a whistle the entire 3 years I owned the car, after flushing it once and refilling it with their stuff.

Yikes. If I was ever caught putting dexcool in a vehicle I'd expect to be shot.

Semi-on topic, anyone have some good links or reads to what coolant SHOULD be used? The best kind? On my previous jeep I used Volvo OEM coolant because it was convenient at the time and I had about 6 gallons. It was a blue color, looked really cool. That cooling system stayed clean as a whistle the entire 3 years I owned the car, after flushing it once and refilling it with their stuff.

o-gauge-steamer said:

So what we have here is a very good example of why you need to use distilled water in the cooling system. Steam distilled water is as close to pure as you can get. No nasty little microbes and certainly no minerals to clog up the works.

RO (Reverse Osmosis) will work but why spend the extra cash? But under NO CIRCUMSTANCES use DI (Deinoized) water. DI is an entirely unnatural material and will do everything it can to re-inize itself which is why it is used in the semi-conductor industry (and others) as a cleaner. DI will disolve your metallic parts. In truth, if you drink the stuff, it will kill you due to metal loss. For instance, Calcium is a metal... Like your bones and teeth?

Click to expand...

this is the truth right here... i had rust issues in my cooling system for quite a while, and then i did a system clean and flush with distilled, and have not had an issue since. i have debated with people who tell you it wont make a difference, and maybe in some locations which have softer water than i do, it wouldnt be as bad, but the rust will eventually come for them.

^^ There you go. And I promise to spell "ionize" properly from now on... I have used Vinegar (Acetic Acid) as a flushing agent for years as it is "biodegradable". Dump as much out of your system as possible and fill it with the Vinegar. Run the engine until it is up to temp, allow to cool and flush. You will be amazed at the garbage that is lurking in a system that has not been on a steady diet of distilled water. After flushing, 50/50 coolant with distilled. This is a reasonable solutiuon for systems that are not as contaminated as the OP's. His is going to take drastic steps or the infection will return...

So I've been doing some research. I bought 4 gallons of SuperTech (walmart) 50/50 coolant that I was going to run for a few weeks, then flush, and refill with Mopar's recommended HOAT or some Zerex. WRONG!!! Prestone, Peak, and SuperTech all contain 2EHA, which is the ingredient in dexcool that causes so many problems. Guess where I'm going today - back to Walmart to return this devil's poison.

O-gauge I like you're idea with the vinegar. Is it ok to run straight vinegar for those first 20 or so break in miles before swapping it? Remember my entire new system is dry, nothing in the block, nothing in the readiator. The last this I want is to overheat upon the first startup lol.

vinegar will rot the inside of your hoses

I've come to realize this is exactly the same type of discussion as oil. Everyone has a different preference, opinion, suggestion, data, test results, backyard experiment, someone's uncle's friend did it and nothing bad happened etc etc. A general consensus I've found though, is that E2HA is bad. And Zerex G-05 (HOAT) is good. I just picked up two gallons of that and some Water-Wetter, hopefully this is the winning silly sauce.