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Broken valve spring

33K views 26 replies 9 participants last post by  JCemenski 
#1 ·
Got a broken valve spring on a 03 Liberty :mad:. Now trying to find a valve spring compressor to do the job. The pretty unique configuration of the V6 and the lash adjuster are narrowing my choices. Does anyone know what type of tool would best fit the job and where to get it?
 
#2 ·
I would think your local auto parts store would have it. If it's a unique tool, your Jeep dealer will stock it, but those tools tend to be expensive, because the dealer doesn't like to have other people do that work.

I just took a look in my Haynes manual, and it said two special tools are needed for the job, but I didn't read the whole procedure to see what those tools are. The valve spring compressor looked normal.
 
#3 · (Edited)
'We don't sell tools...' was the answer from the dealer. Plus the fact that they gave me a replacement valve spring for the 06+ year model (which probably won't work), they said they ran I guess of the 03-05; I guess they really don't want me to work on it. But then again they messed up the ball joints when we took it for the recall thing last year, we had to take it there again a month later. I will never take it there again...

Yeah the Haynes manual was a little vague. I went to every places I could and showed the picture, none of them had it. But I might try anyway with one of those universal spring compressor. I don't see why it wouldn't work, except where the cylinder is at, the master cylinder and brake lines might be in the way. The thing is I don't have to take out the rocker arm since it fell right off when we took the cover off.
 
#4 ·
I ended up using one of those cheap universal valve spring compressor. It wasn't needed to remove the spring since it was broken. I had to grind the hell out of it to make it fit so it won't run into the camshaft and will reach the bottom of the valve seat. It did the job, altough a more expensive tool would probably do a cleaner job.
 
#6 ·
I wouldn't recommend unless you have a problem, it is a HUGE pain. This shoudn't happen anyway, not on a vehicle with less than 89 Kmi on it. The valve springs should last the lifetime of the engine. There is obviously a design defect here.

Apparently, the 3.7L are prone to carbon buildup inside the combustion chamber. You wouldn't believe how much came out of the exaust while the engine was misfiring. There was also significant carbon deposit on the spark plugs too. Also, I am afraid it will happen again. At least another cylinder read compressions above 150 psi (the carbon buildup will shrink the chamber, there fore higher compressions). My guess is the buildup caused the valve to stick, putting stress on the spring. I happen to know (since the dealer gave me the WRONG part) that 06+ models have reinforced springs.

Sorry but changing the springs won't remedy the cause of the problem.
 
#7 ·
Normal high speed diesel 10-15000hrs top end That 24 7 for almost two years. 30,000hrs complete. Inspect rod bearing every five years.
That's all pre light weight common rail tier3 emissions crap.
 
#10 ·
The results were pretty good actually. The hard part was to make the spring compressor work so it would fit the tight space. I tried setting the spring, failed, grinded the tool, tried again, failed, grinded the tool more... It was like a $20 spring compressor. I guess a more expensive tool would have been much easier. Also I had to find a trick to secure the valve in place once I removed the keepers, since the cylinder wouldn't hold pressure. This is the new valve installed. Pink, I know, don't ask me why.
 

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#17 ·
Also I had to find a trick to secure the valve in place once I removed the keepers, since the cylinder wouldn't hold pressure.
Not sure it's even possible on the 3.7 but in the past I have used a piece of clothesline to hold the valves. Turn the crank to get the piston to BDC, shove as much clothesline as you can in thru the spark plug hole then turn the crank by hand until it stops.

With as deep as the spark plug holes are on the 3.7 I'm not sure you could get enough rope in the hole, maybe with a long skinny pair of needle nose pliers. This trick used to work like a charm on the older V-8's. Still faster to use air if the cylinder will hold it.
 
#12 ·
As you wish. This was I believe a OEM compressor, doesn't look anything like how it came out of the box. Now be aware that I only used the tool to set the valve in place. I don't think I would have been able to remove a functionnal valve with it. And if I had to do again, I can tell you I would go spend money on a better tool (and I'm a cheap bastard).

Not sure you would want to do this as prevention, but you're the boss. As you're at it, change the rocker arm and lash adjusters. I managed to drive the thing home and then we revved up the hell out of it thinking it was an ignition issue, so I don't believe the valve would go anywhere. The only time the valve might fall into the cylinder is when you replace the spring (remove the keepers). Then you want to make sure the valve is secured because if it drops you'd have to pull the head and we both know what this means. This was an exhaust valve, and I don't know what could have happens if this was an intake valve, but it looks like it's a non interference engine, or the valve would have been smashed big time. That was my bigger fear all along.

I believe the way to prevent this would be to get rid of the carbon buildup in the cylinders. I mean there was a bunch in that cylinder alone. It all came out of the exhaust, probably due to the unburnt gasoline that cleaned it. The incident happened in a cold morning when my wife started the car to go to work. She kept on driving it but didn't go very far... sticking valve? They must be aware of the problem because the 06+ year models have a reinforced spring.
 

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#15 ·
If you drop a valve in any engine it's going to hit the piston,but yes by definition the 3.7 is a "interference" engine but one of the timing chains would have to break for a issue and that is not likely going to happen,you will know way ahead of time before a chain breaks in 99.99% of all cases.
 
#16 ·
Good to know, I couldn't find anything about the V6, but I did find out the 4 cyl was a non-interference. The thing is even though the spring was broken it was still pushing the valve up - not all the way up, but somewhere in between the open and closed position.
 
#18 ·
I used rope. I tried compressed air, but it just wouldn't hold. The rope painfully did the trick. I slid whatever lenght of rope I could in it then set it at TDC on the compression stroke. It was somehow holding the valve, not all way up, but holding just enough so that it wouldn't drop (all I cared about). I could tell the valve could touch the rope since it was easy to move up and down. This made it difficult because I had to make sure the valve kept close so I had enough room to put the keepers back in place when the new spring was being set.
 
#21 ·
Thanks.

It depends on your year model. My local Jeep dealer gave me the wrong part for the 05-06+ models or so, we have an 03. I didn't have the VIN # so they took a guess and told me they were pretty sure it would fit. This is the part on the left of the picture, and as you can see it's not pink and has some kind of sleeve around it. Our dealer sucks, when I came back to get the right spring, they were out of it (they also messed up the ball joint recall before...). Long story short, I happened to go to Florida for work and picked up the part there... which is pink.

Out of curiosity, were you using a Fram oil filter when this happened?
 

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#23 ·
It ran like garbage, would have a hard time go through RPM, die at idle, shake like crazy, almost impossible to drive. They were two misfire codes (one from the affected cylinder, the other was a domino effect). Compression on that cylinder was 0 psi.
 
#24 ·
More detective work today. 06 Liberty valve rocker dropped off # 4 intake valve and broke the spring, then cam pushed rocker against lifter sideways when lifter was extended and cracked the boss in the head that holds lifter. Also cracked valve cover. I removed head and noticed that the #4 intake valve lifter hole was drilled 3/16 deeper than the remaining lifter holes at the factory. Theory is that engine stopped last time car was used with cam in position where cam lobe extended # 4 intake valve. Overnight oil weeped out of lifter making it squishy. That coupled with poorly machined head left too much clearance between lifter and cam and prolly caused the problem. I read a post today where another owner had rockers dropping off on same clyinder a couple of times. He dropped a 7/16 .080 thick washer into the lifter hole and reinstalled lifter to eliminate the clearance problem. Says its working for three months now. Pro tech oil filter is what is on car. Your spring with the metal cage on it looks just like my 06 Lib exhaust valve.
 
#25 ·
I feel your pain. Exhaust valve it was, yes.

To this day my theories have remained hypotheses. Interestingly this happened when my wife first started it on a cold morning. There is no doubt in my mind that there is a fundamental flaw with these engine heads, or at the very least a major weakness. The fact that they've installed a heat sink on newer models of valve springs represents to me an underlying admission by Daimler Chrysler that something isn't quite right. Perhaps the combination of an inherent design weakness and a contributing factor, whatever it might be, could be what's setting the ground for failure. One of my theories has to do with the oil filter. I learned afterwards that basic Fram filters are junk; I know for a fact that they obstruct the oil flow causing oil pressure to drop (thanks to my XJ's oil pressure gauge). I am also suspecting a faulty check valve causing oil starvation on a cold start. I wish I still had the filter that was on it when failure happened so I could take it apart and inspect the check valve inside it...

I don't know about the lifter hole, but I did notice that when the spring was broken, the valve wouldn't seat properly. In fact I was unable to build air pressure inside the combustion chamber as a mean to keep the valve closed, which is necessary to perform the repair. And once the new spring was installed, I had to hit it with a mallet to seat it right. I didn't think much of it, I thought at the time the valve spring was helping the valve seat and this was normal. Something to add to the mystery.

As for the rocker arm it came right off when we popped the cover. The valve spring's tension normally keeps it in place. Maybe in the case of the post you read, abnormal wear caused too much clearance. I would say I don't have any particular reason to believe that the rocker arm was to blame here.
 
#26 ·
Recap - # 4 intake valve spring broken. Yep, the hole in head casting where the #4 intake valve lifter goes was .052 deeper than the other lifter holes in the head casting. Holes are also poorly drilled (not bored). I may put a 7/16 in washer in the hole before reinstalling lifter. It's actually the lifter that maintains clearance between cam and rocker and not the valve spring. The valve stem height is fixed by the valve seat. The lifter height is variable based on oil and the spring inside the lifter. Of course if the valve spring is weak or broken this is not the case. Enjoying the discussion. Thanks
 
#27 ·
I agree got 02 libby rennegade and 2 broken intake springs and 2 locked lifters got new parts from mopar. valve did not hit piston head. Should I fix if or will it keep happening. Motor was swapped 3 years ago with jasper remanned longblock. Only has 27000mi. Worth fixin? Or get another motor??
 
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