Broken Timing Chain on 4.0L after 40,000 miles | Ford Explorer Forums - Serious Explorations

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Broken Timing Chain on 4.0L after 40,000 miles

superdolfan

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Year, Model & Trim Level
2005 Explorer
Hope someone out there can answer a couple of questions regarding my parent's Explorer.

The vehicle is a 2005 Explorer with a 4.0L engine.

A couple of weeks ago my mom was driving down their road when she heard a loud noise. She thought she had hit a pothole, but the vehicle continued to run. She got home, turned the vehicle off and went inside. The next morning she tried to turn the vehicle on and it would not start. She had it towed to their local mechanic who does all their service on the car. He diagnosed a broken timing chain and said that the engine needed to be replaced. The vehicle was purchased new, has had the oil changed every 5,000 miles with synthetic oil, and all maintenance, scheduled and regular, has been performed by either the dealer or the local shop. At the time of the diagnosis, the vehicle had 39,000 miles.

A question that has been asked about this is "Why was it not towed to the dealer?". My parents live in a small town in the country and the dealer is good distance away. Once the mechanic determined what was wrong, he contacted the dealer who advised the mechanic that the vehicle was out of warranty, that there was nothing they could do. Sidebar - At the time of purchase, the dealer sold my parents a 84 month/36,000 mile extended Ford warranty. Needless to say, although the months had not expired, the mileage had.

The information given to the mechanic by the dealer was given to my parents and they decided to order a remanufactured engine to replace the bad one at a cost of $4700, which included installation. At this time I had not been made aware of the situation. The mechanic did offer to try to find a junk yard engine, but they declined this.

After the engine had been ordered and was enroute, I was made aware of the situation and I contacted the dealer. The service writer who answered greeted me by name, even though we had only spoken once before years ago, and said he was expecting my call, that he had all of the paperwork on the vehicle in front of him. I was puzzled by this. He indicated that because the vehicle was out of warranty, there was nothing they could do. I asked to speak to the service manager. He was a little more helpful, and asked where the vehicle was. I told him that it was at a private mechanic who had already dropped the engine prepping it for the new engine. He asked why it had not been brought to them in the first place. I told him because his service writer had said there was nothing Ford could do. He said that there really was nothing he could do either now that the engine was no longer in the vehicle, but that he would contact Ford anyway. He called me the following day and said that Ford could do nothing about it.

I deal with comptuters and networks and know very little about engines. I have been told by more than one person that a timing chain doesn't go on a 4.0L 2005 engine with 39,000 miles. I am curious to know if a repair done in 2009 might be related to the failure, which is why I am here asking the experts.

In September 2009, when the vehicle had 33,000 miles, it was making loud noises and the stopped running. My mom had it towed to the dealer. The following work was performed (this is directly from the work order):

CUST STATES VEHICLE SHUT OFF WHILE DRIVING DOWN THE ROAD -WONT RUN (TOWED IN)
CAUSE: VERIFY CONCERN, IDS TEST - NO CODES, MONITOR PIDS WHIL E CRANKING-NO RPMS,CK CKP-HARMONIC BALANCER COMING APART-DAMAGED CKP,REPLACE HARMONIC BAL 6312A PULLEY ASSEMBLY - CRANKSHAFT -

REPLACE (6a312/6B321) -L 109 WESP 0.80 N/C
1 4L2Z*8620*EA V-BELT N/C
1 8L2Z*6B321*A PULLEY - CRANKSHAFT N/C


That's all of the work order. I asked for a detailed work list, which they supplied but it's not legible.

The mechanic has replaced the engine with a rebuilt one. It carries a 36 month/100,000 mile warranty on it. My parents have transportation again, even though it set them back over $5,000 after sales tax.

I'm a little peeved with Ford and am curious if one repair *not done right* caused the timing chain to go bad, which caused the engine to fail.

Any insight would be greatly appreciated!
 



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harmonic balancer

I have no first hand experience with the 3rd generation harmonic balancer but from what I've read on the forum they are prone to early failure. Here's a link to a thread I started to encourage members to document the problem: Harmonic balancer failure

The damage and repair for your occurrence is typical. The crankshaft position sensor, balancer and serpentine belt were damaged and replaced.

In my opinion it is unlikely that the harmonic balancer failure is related to the timing chain failure. Ford began manufacturing the SOHC V6 engine in 1997. In just a few years timing chain related problems surfaced and the components have been upgraded several times. To my knowledge there were no additional upgrades after 2002. While a failure at 40,000 miles is very uncommon for a 3rd generation it is quite possible due to the age of the vehicle. I suspect that the "plastic" timing chain guides fatigue with time and then fracture. Not all of the guide sections are metal reinforced so when those plastic sections fracture the unit falls apart.

To learn more than you probably want to know about the SOHC V6 timing issues read some of my Helpful Threads by clicking on the link in my signature.
 






It is definitely not related to the balancer. I have had a couple of 4.0L SOHC motors break the camshaft sprocket bolt off and have had valve springs break which drops the valve and causes serious engine damage. Do they know the exact failure?
 






I agree with the OP a timing chain should not go at 39,000 miles. I have had similar experiences with other Ford "warranty" issues and hence why my current '04 Exploder will be my last Ford product I will ever purchase. I know that other makes can have similar issues and no car is perfect, but Ford will never get another dime of my money.
 






I'm currently sitting with a 4.0 my self that just stopped when we were driving to work. We found no compression so we took the front off and found a broken timing chain. My question would be "why replace the whole motor for a $60 part?"
 






I'm currently sitting with a 4.0 my self that just stopped when we were driving to work. We found no compression so we took the front off and found a broken timing chain. My question would be "why replace the whole motor for a $60 part?"

Do you have the SOHC or OHV 4.0L? The SOHC V6 is an interference engine. Often when a timing chain breaks on it while driving the pistons strike and damage the valves. If an owner has to pay a shop for labor and parts to replace the valves it may be cheaper to replace the engine with one from a salvaged vehicle. Since you seem to be mechanically inclined and have access to tools and a place to work you can save a lot of money by doing most of the work yourself. There can be four timing chains on the SOHC V6. Which timing chain is broken on your engine?
 






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