3.7 oil crud probelm

[Conundrum2006]

After the engine was replaced in mine within a couple thousand miles the upstream oxygen sensors shot craps. Nothing like spending several thousand dollars on the vehicle only to have the check engine light pop on.

Nothing that bad has happened yet. But I did have the left rear caliper start sticking when we were out of town so I had to do a brake swap in a drive way of the people we were visiting. (yay can't get more red neck than that!)

Put about 800 miles on the new motor 700 miles on the highway. Get about 19 mpg flirting with 20 mpg depending on the traffic and my lead foot.

Just complete the autopsy on the old motor. I'll be posting the pics soon. Would have got it done last earlier but I had to redo the waterpump, power steering, idler pullys basically everything that spins on the front of our 90s Cherokee. The new idler pulley I put on a few months ago broke taking out a cooling pipe and bracket the ac compressor sits on.
Most frustrating thing is the idler pulley that broke was supposedly a good name, didn't last 500 miles. Hunted down all Mopar replacements, especially since the kids love to ride in this jeep.

I'll be back in a few once I figure out how to handle the pictures.

 

[Conundrum2006]

Pictures of the timing chains. You can see pieces of broken guide rails to the side. I guess the passengers side was the one that made it down to the oil pan.

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All of the cylinder head bolts looked great except for two. One on each side, top (near the intake) middle of the motor nearest the back of the motor.

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and you can see in the background some of the crud the squirrel of whatever left on the motor.

 

[Conundrum2006]

Ok now on to the passengers side cylinder head. The gasket did not look blown to me. I didn't see any sign of a cooling problem on this side. I pulled this side first because I had two low readings in the first compression test, the second test was fine. My only guess is some of the nut shells fell in and kept the first test from seating correctly.

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passenger side cylinder head.

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head gasket , and detritus in the cylinders courtesy of the rodentia.

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Opposite side of the gasket.

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Back most cylinder.

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Middle cylinder

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Front most cylinder.

 

[Conundrum2006]

Drivers side Cylinder head.

Again no sign of a cooling leak. But this side looked much cleaner than the passengers, maybe the the PCV on the passengers side lead to more build up. The flush looks like it did more here, only had to dig out two of the bolts free from built up crud.

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Driver side Cylinder head.

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Gasket

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The other side of the gasket

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Closeup of front most cylinder

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Closeup middle Cylinder

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Closeup of the back cylinder



And that it for the pictures. A lot didn't focus correctly. No idea what the phone was trying to take a picture of.

 

[Conundrum2006]

From what I've seen I think this motor died of major neglect. Unless there is something subtle I'm missing. Thought there was a possibility of BHG because there was a record of the rad cooling fan being replaced a few years back.

What do you all see with the block and cylinder heads?

 

[ltd02]

From what I've seen I think this motor died of major neglect. Unless there is something subtle I'm missing. Thought there was a possibility of BHG because there was a record of the rad cooling fan being replaced a few years back.

What do you all see with the block and cylinder heads?

I did blow my HGs due to an overheat. I could see bad spots on the gaskets and my heads warped. Coolant went into the oil. :favorites68:

I had tons of carbon on most pistons. I think you are correct and this was just gross neglect. The cylinders and combustion side of the heads don't look all that bad to me. The cam side is another story! arty52:

 

[TwoBobsKJ]

From what I've seen I think this motor died of major neglect. Unless there is something subtle I'm missing. Thought there was a possibility of BHG because there was a record of the rad cooling fan being replaced a few years back.

What do you all see with the block and cylinder heads?

That engine went a LONG time between oil changes before you got hold of it :emotions34:

That's a lot of crud, even on the front of the timing chain sprockets - and that's AFTER you ran a cleaner through it. The heads actually don't look all that bad but obviously can't tell if they're warped from the pics.

Your earlier comment about the swap being straightforward - and in fact, easy - is what I experienced as well. There really isn't that much to it, especially if you're swapping in a block from the same generation as the original engine so there's no messing with the timing sprockets.

Thanks for the autopsy pics! :waytogo:

Bob

 

[Conundrum2006]

I did blow my HGs due to an overheat. I could see bad spots on the gaskets and my heads warped. Coolant went into the oil. :favorites68:

I had tons of carbon on most pistons. I think you are correct and this was just gross neglect. The cylinders and combustion side of the heads don't look all that bad to me. The cam side is another story! arty52:

I was surprised how clean it was. Other than the topside of course. I was almost certain there would be some sort gasket failure just because the gunk was so thick. It looks rather clean, considering everything.

Guess I can clean and rebuild. Sort of a shock, pretty much wrote it off.

 

[Conundrum2006]

That engine went a LONG time between oil changes before you got hold of it :emotions34:

That's a lot of crud, even on the front of the timing chain sprockets - and that's AFTER you ran a cleaner through it. The heads actually don't look all that bad but obviously can't tell if they're warped from the pics.

Your earlier comment about the swap being straightforward - and in fact - easy, is what I experienced as well. There really isn't that much to it, especially if you're swapping in a block from the same generation as the original engine so there's no messing with the timing sprockets.

Thanks for the autopsy pics! :waytogo:

Bob

The swap was easy, and the peace of mind knowing the engine is in superb shape. If anyone is in the same boat, find the newest 3.7 with lowest miles, it'll end up being a lot cheaper than a rebuilt motor and with OEM quality.

That amount of crud left after flushing they must have had annual oil changes for the first 7 years.

Other motors I'm more familiar with this one look good from what I saw but this motor has confused me before.

Guess I can clean this and rebuild it. Maybe someday I can find a 5 speed KJ with a bad motor, the Commander if not quite what I like for off road.

 

[Leeann]

That looks slightly better than the 2.2L the shop pulled out of the 1990 Dodge Omni my roommate's dad bought for her in '93, fortunately also buying the extended warranty from the woman (he knew he needed it).

The little old lady'd never had the oil changed. Just went to the full-service gas station and had them add oil as needed. For 35,000 miles.

The shop said there was no point in attempting to clean and resurrect the old engine...they got a Dodge rebuilt long block for less than the shop time to try to clean it. And, thanks to the extended warranty, her dad paid a whole $150 for the repair work, after paying only $1000 for the little tank.

 

[Conundrum2006]

That looks slightly better than the 2.2L the shop pulled out of the 1990 Dodge Omni my roommate's dad bought for her in '93, fortunately also buying the extended warranty from the woman (he knew he needed it).

The little old lady'd never had the oil changed. Just went to the full-service gas station and had them add oil as needed. For 35,000 miles.

The shop said there was no point in attempting to clean and resurrect the old engine...they got a Dodge rebuilt long block for less than the shop time to try to clean it. And, thanks to the extended warranty, her dad paid a whole $150 for the repair work, after paying only $1000 for the little tank.

The Omni! Hadn't thought about that car in years, VW Rabbit clone that at one point had a VW engine and transmission.

One of my first jobs I worked with a guy who only changed his filters, with a oil change maybe once year sooner if he hit 10k. To his credit that old 70s Cadillac never died years later I heard he gave it to his wife's nephew for demolition derby.

I was just thinking about it today in the 1980s I thought oil change recommendations being 7500 to 10000 miles, then in the 1990 it dropped to 3 to 5k. Now some manufacturers are going back to 75000 to 10k with synthetic oils. Some of the newer jeeps monitor driving habits to set the oil change intervals.

After seeing what neglect does to these motors and knowing how sensitive these motors and many of the early 2000s vehicles like my ford 5.4 are to oil flow, no way I'm going to push my luck.


My brother in-law fubar'ed his nice Hyundai by not changing the oil for it has got to be at least 30k in several years. I'm told the oil was so thick and dark it looked like 1940s oil. The shop almost couldn't get the oil filter out.
He knows better, I know he knows better because we worked on cars together.
Gave him all the oil and additives I had left from trying to save this jeep motor, I'll report back if we are able to save it. Since it still runs we are starting with Rotella oil mix.

BTW my sister has a similar car, recently I changed a leaking valve gasket. Incredibly clean motor especially since it's just ticked over 200k miles. She took it in for oil changes not religiously but regularly. IMO Proving an once of prevention and all that.

 

[ltd02]

Geez, Omni day! My friend had a late 80's 2.2L Plymouth Omni TC3. He wouldn't change his oil either. I finally changed it after a couple years of abuse. I remember opening the drain plug and nothing came out. Finally stuck a screw driver in there and out chugged the sludge that was once oil. Maybe a quart and a half tops. I put some good stuff in it and a new filter and he drove that thing for two more years before he totaled it. His had a Mitsubishi motor. Tough little bugger!!

I remember my dad saying how back in the mid/late 40's he serviced fleet vehicles at a Pontiac dealership and they changed oil every 1000-1500. Of course they filtered their own oil and reused it. Dumped it down through a two story silo filter of mainly sawdust. Not even sure if many of those vehicles had full flow filters back then. Bypass filters didn't do a good job. I think full flow were like mid 40s and spin ons were'nt standard until the mid 50s.

 

[Conundrum2006]

Follow up on the crud problem.

took the oil pick up and let it sit in a glass of kerosene, testing at different intervals to see how the crud covering the screening cleaned up.
Yeah, I was screwed either way, after one hour of soaking it didn't remove much. In fact when picked up it like to drain the kerosene rather drain out the tube than go back though pick up screening.

I checked often at first every other hour no major change. Left it to sit a few hours shy of 7 days. Still no major change visuallly but it would drain out the screening better.

Was hoping to find out how many hours it would take kerosene to dissolve oil crud/gunk, in my case with this heavy coating, I don't think it would have mattered how long it soaked. There would be improvement but some abuse can't be undone with good maintenance after the fact.

Although the heat of a motor running and pressure of the oil pump working might have made a significant changes. couldn't test for these so I tested the cleaning of the pump screen, thought being if it could dissolve enough crud it would prove given enough time the motor might have pulled though and cleaned itself up. Also if it could dissolve the oil pan crud enough to drain would have helped too.

My case was a serve case and dropping the pan was the only answer.

BTW looking at the My carfax app, updating maintenance we've done I noticed the oil change log had a gap in the records form 56k to 109k, had assumed before that was gaps in their rerecords not covering all oil change places but I guess we can say it is gospel now.

I'll post a few pics from my phone just to show what did happen for any that come after with a similar problem.

 

[Conundrum2006]

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starting point.

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1 hour later

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about 1 day later (can't see my time stamp)

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day of soaking

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6 days of soaking

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after 6 days (photo taken at night)

 

[TwoBobsKJ]

Holy crap!

That's just inexcusable but sadly more common than I'm sure I realize. I just hate seeing good engines and such abused like that.

I agree with your assessment - that engine was too far gone :favorites68:

Bob

 

[Conundrum2006]

Power of the purple cleaner. (This cleaner was from Lowes. ) 50/50 mix so it was pretty strong. Saw results after 1 hour. These pics are from a 12 hour soak. (

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Obviously it can't be added to the motor and left to sit, but it does wonders in clean up after its removed


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[Conundrum2006]

Ugh.

May have spoken too soon. Dropped the transmission pan to do the oil because for whatever reason the commanders do no have a drain or dipstick. Supposed to be "lifetime fluid" on the Mercedes nag1 transmission.

Found some needle bearing and bearing housing on the magnet.
The transmission was driving fine, smooth shifting etc. Only changed the fluid because it looked dark which is a bad enough sign. Only noticed this because I replaced the condenser which is the transmission cooler too.

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Piece by the quarter is two same size pieces. The needle bearings are tiny and I haven't found too many.

Obviously this is not good. Anybody seen similar things in other jeep transmissions ?


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[HoosierJeeper]

That doesn't sound good. I have a WK with the same setup as your XK. No dipstick either, I should get one. Tube is there.

 

[renegade 04]

I would buy a dip stick for the transmission because you should check the fluid every so often. I check mine every 1000 miles due to its age and fluid leak.

 

[Conundrum2006]

I found the dip stick from my f150 transmission give a decent reading , someone suggested looking up a dipstick for a Mercedes 722.6


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