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Discussion Starter #1
In my initial post to this forum back in July, I mentioned that I had overheating problems and that I was taking steps to fix them the best that I could. The steps I took included:


New Radiator
Flush Coolant System
New Thermostat
Change Oil
Replace Belt Tensioner


Even after these repairs I knew that I might fall prey to the ill-fated head gasket issue that is talked about on Commanders. As my repairs did not fix the overheating issue and now I was getting a low oil pressure light and smoke coming from the engine, I decided to pass it on to a professional.


At an estimated cost of $2,000, they completed the following:


Head gasket replacement
Machine Heads
New Oil Pump


Then added on an additional $400 for new cylinder head on Driver's side after failing to achieve desired result.


They rebuilt the engine twice. They put everything back together and fired it up today. There is now compression on all cylinders. There is oil pressure. But there is a knocking noise.


The mechanic is done. He is giving back the vehicle and giving up. He doesn't know what else could be wrong and suggested I look for a Dodge or Jeep pro that could tackle this.


They believe that there is a lower engine knock. I don't have enough knowledge to diagnose this. They also suggested that the timing chain tensioner might be faulty. I don't know how they wouldn't have seen that when they put it back together.


I don't want this to run much longer, but maybe someone on this forum has heard about these same issues and could give some advice before I shell out any money for repairs.


Is the engine toast? Is the engine knock due to an oil pressure issue? Could the engine bearings be going bad, and if so, why do I have good compression at the top? Could something have fallen into the engine that is knocking around?


I know it's hard to diagnose from afar, but I am frustrated, they are frustrated, and I just need to get my Commander running.


Thanks
 

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If you ran it with low oil pressure you may have spun a lower rod bearing and that is where the knock is coming from. I have been nickle and diming a 4.7 in a WJ for years. It never ends. That is why the Commander has a 5.7
 

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It is unfortunate you have found yourself in this predicament. From the information you provided, you may have an issue in the lower end of the engine as was indicated by the above poster. If I were you I would take possession of your vehicle from the mechanic and find someone who can properly diagnose your lower end issue. The low oil light indicates oil starvation due to a worn oil pump and this is where the damage occurred to the lower end. The overheating issue is unrelated, so you have multiple issues going on.

As I see it you have a couple of options. If you own the car outright, you may consider trading it in and getting out of it completely. If this is not a viable option for you then I suggest you find a knowledgeable mechanic who can properly diagnose the engine noise. The older more experienced mechanics can do this. There are some who can tell a rod knock from a main bearing knock. That is who you need to find.

But lets say for discussion sake they determine you have either a rod or a main bearing issue that is causing the knock. At this juncture, I would be looking for a remanufactured short block and have it replaced outright. Of course if you're handy and want to take it on yourself, that would be my vote, but from your conversation, it looks like you would rather leave this type of effort to others (and theres nothing wrong with that).

So, to recap - find an experienced mechanic to properly diagnose your noise. Cost should be minimal to do this. If the noise is in the lower end of the engine (which I suspect given the information provided), you either offload the vehicle entirely and get into something else or bite the bullet and get a remanufactured short block. If you're going down this rabbit hole, you may as well price in a complete remanufactured engine just so you know where your financial limits are. Personally, I would stay away from any used engine replacements. It is a headache you do not want.

I feel for your situation and understand your frustration and wish you all the best! :wink3:
 

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Looks like you have changed quite a bit, did you look at the water pump? I was just fighting an overheating issue in another thread. Water pump is cheap and on the v6 its super easy to change, not sure about the v8. Its has rather cheap looking plastic impeller. If there is enough room on the v8 to get it out with out too much hassle it would be worth taking a look, or just pop in a new one while you're in there.
 

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Discussion Starter #5
Looks like you have changed quite a bit, did you look at the water pump? I was just fighting an overheating issue in another thread. Water pump is cheap and on the v6 its super easy to change, not sure about the v8. Its has rather cheap looking plastic impeller. If there is enough room on the v8 to get it out with out too much hassle it would be worth taking a look, or just pop in a new one while you're in there.



The water pump was one of those things that the mechanic was supposed to look at, but I never got confirmation on whether it was done. Once I got the car back, I tried to start it up. It ran for a minute, and then backfired out of the air intake, popping the filter up in the process.


The tow truck driver who brought it home for me said that this means the timing is off. The mechanic thought that the timing tension might be off too, so now I'm really hoping that all of this rough idling and knocking is being caused by a timing issue.


It would be a shame to have to scrap this engine. I have 2 new cylinder heads, new valve covers, new head gasket, new oil pump, new belt tensioner, and then all the various gaskets, etc.


Going to try to make a new friend over at the Jeep dealer and see if maybe they want to educate me for beers...or cash. I just want this fixed now!!:laugh2::laugh2:
 

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The water pump was one of those things that the mechanic was supposed to look at, but I never got confirmation on whether it was done. Once I got the car back, I tried to start it up. It ran for a minute, and then backfired out of the air intake, popping the filter up in the process.

The tow truck driver who brought it home for me said that this means the timing is off. The mechanic thought that the timing tension might be off too, so now I'm really hoping that all of this rough idling and knocking is being caused by a timing issue.

It would be a shame to have to scrap this engine. I have 2 new cylinder heads, new valve covers, new head gasket, new oil pump, new belt tensioner, and then all the various gaskets, etc.

Going to try to make a new friend over at the Jeep dealer and see if maybe they want to educate me for beers...or cash. I just want this fixed now!!:laugh2::laugh2:
@truehemingway;

Let us know what you find out, I'd be interested to know.

I never heard you mention anything about getting any DTC's in the EVIC - are you receiving any, or, have you had your DTC's pulled yet by your previous mechanic? I'd have thought that would have been the first thing he would/should have done.
 

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Discussion Starter #7
Time for an update:

So, after almost giving up and thinking about selling my Commander, I decided to dive into a full-on engine assessment in the parking lot of my condo. I have had to do this in stages and very secretly because the HOA doesn't allow auto repair, but the end is near:

Removed and changed all spark plugs. Started engine up and it ran really rough. In fact, it ran so rough that it only fired on one side of the engine. On the other side, the plugs were sitting in fuel and when I pulled the distributor connectors, you didn't hear any change in the RPMs, so no spark.

Time to dig deeper. The mechanic that had worked on my vehicle before claimed that they rebuilt all of the seals including the head gasket, machined the cylinder heads, and replaced the valve cover gaskets amongst others. I started breaking down the engine and discovered some frustrating issues:

Firstly, this may not be an issue, but they used a liquid gasket on the timing cover which seeped into the holes where the coolant circulates to the water pump and gunked up the entry. Secondly, they didn't tighten several bolts on the oil pan after replacing the gasket so it was leaking oil underneath. Finally, and most critically:

They didn't tighten the bolts to one side of the timing chain tensioners properly and during the initial re-fire of the engine, two of the plastic arms had broken off and were floating in the oil.

So, that's where I'm at now. I have owned this Commander for 6 months, have driven it 1 day for all of 30 minutes. I am just waiting for the new timing setup to show up, but Amazon lost it in the mail!! So, even though the fates are against me, this engine will be rebuilt!!

Question about that gasket, though: I am receiving the standard fabric gasket for the 4.7 engine in my timing chain kit. Is this not sufficient for the timing cover? Or am I supposed to use some additional make-a-gasket around the bolt holes, etc. to seal this up?

Thank god for YouTube because even with my complete repair manual, I am a visual learner and need those timing routing videos to help get this done!!
 

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Discussion Starter #8
@truehemingway;

Let us know what you find out, I'd be interested to know.

I never heard you mention anything about getting any DTC's in the EVIC - are you receiving any, or, have you had your DTC's pulled yet by your previous mechanic? I'd have thought that would have been the first thing he would/should have done.
I had only one code, (P0300) one for random misfire, which is what they used along with the overheating issue and white smoke to diagnose this as a blown head gasket. I found out later after picking up the vehicle that they were certified mechanics for Toyotas and they admitted that they had never worked on this engine before. Really frustrating because they seemed so confident when I dropped it off, and they are a general repair mechanic, the largest one around (I live in a small town).
 

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I had only one code, (P0300) one for random misfire, which is what they used along with the overheating issue and white smoke to diagnose this as a blown head gasket. I found out later after picking up the vehicle that they were certified mechanics for Toyotas and they admitted that they had never worked on this engine before. Really frustrating because they seemed so confident when I dropped it off, and they are a general repair mechanic, the largest one around (I live in a small town).
I understand, that can make troubleshooting somewhat more difficult when you don't have a legit Chrysler/Jeep dealership around to fall back on when things start seeming hopeless.
 

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Guessing you might already have it back together? Any update?
Sounds like you figured out its definately a timing issue, which when misfiring badly, can certainly produce a lnocking sound, but only the keenest ears know best where the knock is coming from.
Good call on tearing it down yourself to get a good look. Be very careful to realign the cam / crank timing marks per spec, and pay close attention setup instructions, everything is relative to #1 cyl @ TDC. Hope you got instructions with your timing set.
 

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Time for an update:

So, after almost giving up and thinking about selling my Commander, I decided to dive into a full-on engine assessment in the parking lot of my condo. I have had to do this in stages and very secretly because the HOA doesn't allow auto repair, but the end is near:

Removed and changed all spark plugs. Started engine up and it ran really rough. In fact, it ran so rough that it only fired on one side of the engine. On the other side, the plugs were sitting in fuel and when I pulled the distributor connectors, you didn't hear any change in the RPMs, so no spark.

Time to dig deeper. The mechanic that had worked on my vehicle before claimed that they rebuilt all of the seals including the head gasket, machined the cylinder heads, and replaced the valve cover gaskets amongst others. I started breaking down the engine and discovered some frustrating issues:

Firstly, this may not be an issue, but they used a liquid gasket on the timing cover which seeped into the holes where the coolant circulates to the water pump and gunked up the entry. Secondly, they didn't tighten several bolts on the oil pan after replacing the gasket so it was leaking oil underneath. Finally, and most critically:

They didn't tighten the bolts to one side of the timing chain tensioners properly and during the initial re-fire of the engine, two of the plastic arms had broken off and were floating in the oil.

So, that's where I'm at now. I have owned this Commander for 6 months, have driven it 1 day for all of 30 minutes. I am just waiting for the new timing setup to show up, but Amazon lost it in the mail!! So, even though the fates are against me, this engine will be rebuilt!!

Question about that gasket, though: I am receiving the standard fabric gasket for the 4.7 engine in my timing chain kit. Is this not sufficient for the timing cover? Or am I supposed to use some additional make-a-gasket around the bolt holes, etc. to seal this up?

Thank god for YouTube because even with my complete repair manual, I am a visual learner and need those timing routing videos to help get this done!!
You need to hold that shop's feet to the fire. The 4.7 is an Over head cam engine. If the timing was off after receiving back, they put it that way. You have to retime it after you take off and replace the heads the cams are on top of them. Tell every one you know not to use that shop!
 
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