Update: 4.0 SOHC Timing Problem

Question:

Sorry, Steve…. not up to me to decide a dealerships or Fords policy. Since the right bank cam timing is off, the only way to check for cylinder sealing would be a leakdown test (the mechanical compression test would mirror the results of the relative compression test). As far as performing the job yourself… that will be for you to decide but I will warn you that the motor comes out and special holding tools are required. If there are no bent valves as yet, it is very easy to bend them through inappropriate actions. If you do decide to repair this yourself, I heartily recommend obtaining a service manual and reading the pertinent section(s) thoroughly. Good luck. — Jim Warman

– Hide quoted text — Show quoted text -> Here is the most recent info: > Vehicle: 1998 Explorer Sport, 4.0 SOHC V6, 4WD, Automatic, 60K miles. > History: Dealer did front timing chain tensioner around 50K, no > charge. > Problem: Suddenly sounds like a diesel. > Status: Took to dealer for troubleshooting. They have identified the > likely problem to be the rear timing cassette. Because the rear chain > drives right OC, the cam timing is out on the right side bank. A > "relative" compression check shows low compression on right side > cylinders. They say that Ford might contribute 80% of the first $1000 > to replace the rear cassette, however I would be responsible for any > cost associated with any other damage this created (such as valve to > piston damage, etc.). Thought of having a manual compression check > pulled on those 3 cylinders to see if any obvious damage (ie bent > valves) is evident. I was told that this problem is not related to the > issue with the front chain that drives the left side OC as that had a > root cause related to an oil feed problem on start-up. > My thoughts and Q’s: 1) The similarity in issues for both front and > rear, coupled with the some $ coverage from Ford leads me to suspect > the issue is in the design. 2) Although the issue with the front is > well documented, have others experienced problems with the rear? 3) Is > Ford’s contribution reasonable under the circumstances? 4) Am I better > off tearing it apart and fixing it myself (have done this many times > in my younger days) 5) This Explorer is my fifth new vehicle. The > first 2 were Olds autos to 200K+ miles, a jeep traded-in at 80K miles, > and a Pontiac auto still driven with 80K miles. None of these vehicles > had a major issue like this that was not covered by the manufacturer > 100%. > Thoughts anyone!!  -Steve

Response:

Here is the most recent info: Vehicle: 1998 Explorer Sport, 4.0 SOHC V6, 4WD, Automatic, 60K miles. History: Dealer did front timing chain tensioner around 50K, no charge. Problem: Suddenly sounds like a diesel. Status: Took to dealer for troubleshooting. They have identified the likely problem to be the rear timing cassette. Because the rear chain drives right OC, the cam timing is out on the right side bank. A "relative" compression check shows low compression on right side cylinders. They say that Ford might contribute 80% of the first $1000 to replace the rear cassette, however I would be responsible for any cost associated with any other damage this created (such as valve to piston damage, etc.). Thought of having a manual compression check pulled on those 3 cylinders to see if any obvious damage (ie bent valves) is evident. I was told that this problem is not related to the issue with the front chain that drives the left side OC as that had a root cause related to an oil feed problem on start-up. My thoughts and Q’s: 1) The similarity in issues for both front and rear, coupled with the some $ coverage from Ford leads me to suspect the issue is in the design. 2) Although the issue with the front is well documented, have others experienced problems with the rear? 3) Is Ford’s contribution reasonable under the circumstances? 4) Am I better off tearing it apart and fixing it myself (have done this many times in my younger days) 5) This Explorer is my fifth new vehicle. The first 2 were Olds autos to 200K+ miles, a jeep traded-in at 80K miles, and a Pontiac auto still driven with 80K miles. None of these vehicles had a major issue like this that was not covered by the manufacturer 100%. Thoughts anyone!!  -Steve

Response:

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