htsmeister
Member
- Joined
- May 24, 2009
- Messages
- 33
- Reaction score
- 6
- City, State
- Oregon
- Year, Model & Trim Level
- 2006 Limited,1996 Limited
Hi all,
Well, proud to say I finally got my '06 Limited back on the road. Unfortunately, after a week, it is down again.
Long story short, pulled the engine to do the exhaust manifolds as I just could not get the manifolds off while it was in the vehicle. While I was in there, I did front and rear seals, oil pan, oil filter housing gasket, timing set including phasers, and general tidiness. Even converted to full synthetic (I like Castrol). The intake was not pulled.
After a week, all good, so gave it back to the wife. She takes it out for the first errand. On the way back home, the serpentine belt shredded, whipped around and broke the left cam position sensor connector, and destroyed the fan connector. Got that all fixed (had to eliminate fan connector) and all seemed good.
Now the fun begins...
Took it out for a long drive through the country roads. No issues. Once I got to the freeway (about 20mins away), I stomped on it. No issues. No issues with cruising or passing. Turned around at the next exit (about 2 miles), and stomped on it again. At about 4500rpm, the engine appeared to cough, then it started ticking. Coasted to the next off ramp in neutral and pulled over; It sounded mechanical, from left side valve train. Limped it home.
Fast-forwarding a bit... pulled the valve cover, found bent exhaust valve on #8. See images.
Additional backstory:
> After a few days of driving after the post-install startup, got P2015 a light misfire on #8 cylinder. Swapped positions plugs (#7.#8); no change. Restored plugs, swapped coils; no change. Wiggled the fuel injector and problem went away. Maybe just a small leak. at the o-ring...
Root cause?
1. Hypothesis #1: Since the #8 cylinder seemed to have early warning sign, perhaps the valve was bent slightly when popping off this rocker (along with intakes on #5) to relieve stress on the cam for the phaser and timing chain replacement. This seems like the most likely suspect.
2. Hypothesis #2: Something happened to the intake manifold charge plate for #8 (e.g. came loose, dropped a screw). No damage or scratches noted on the spark plug. I do not have a bore scope and even with a mirror, I can't really see down in the cylinder.
3. Hypothesis #3: Serpentine belt break caused some issue with timing when it knocked off the cam position sensor. Seems like more than one valve would have been affected.
At this point, it is clear that the head needs to be removed and the cylinder inspected.
Some questions:
1. Any other ideas here on what happened?
2. Assuming the head and piston are basically ok, is it cheaper to buy a a refurb head or get it done locally?
3. If anyone has purchased a refurb head, any recommended source for quality and good price? I see Rock Auto has them.
4. Anyone have experience with new heads without doing anything on the bottom end? Vehicle has 182k, but has always been well maintained and is near mint condition. No plan to sell. I am hesitant to do a compression check on the other cylinders with the bent valve situation. when I did the oil pan gasket, I checked out the crank and didn't see any issues with freeplay or wear.
5. What about just replacing the valve, guide, and seal? Kind of seems silly not to do all.
6. What are the (mechanical) risks of only doing one head? Not trying to cheap out, just trying to work out the budget and the time.
7. Do in car or pull engine?
8. Bag it all and buy another engine? New heads and associated parts (no labor) ~$1200. Seems I can pick up a used one with low miles for ~$1000-$1500. Might cheaper from wrecking yard. Value of vehicle ~9k, but it has sentimental value (I can hear the laughter now...), so no plan to sell.
Thanks for any and all input.
Well, proud to say I finally got my '06 Limited back on the road. Unfortunately, after a week, it is down again.
Long story short, pulled the engine to do the exhaust manifolds as I just could not get the manifolds off while it was in the vehicle. While I was in there, I did front and rear seals, oil pan, oil filter housing gasket, timing set including phasers, and general tidiness. Even converted to full synthetic (I like Castrol). The intake was not pulled.
After a week, all good, so gave it back to the wife. She takes it out for the first errand. On the way back home, the serpentine belt shredded, whipped around and broke the left cam position sensor connector, and destroyed the fan connector. Got that all fixed (had to eliminate fan connector) and all seemed good.
Now the fun begins...
Took it out for a long drive through the country roads. No issues. Once I got to the freeway (about 20mins away), I stomped on it. No issues. No issues with cruising or passing. Turned around at the next exit (about 2 miles), and stomped on it again. At about 4500rpm, the engine appeared to cough, then it started ticking. Coasted to the next off ramp in neutral and pulled over; It sounded mechanical, from left side valve train. Limped it home.
Fast-forwarding a bit... pulled the valve cover, found bent exhaust valve on #8. See images.
Additional backstory:
> After a few days of driving after the post-install startup, got P2015 a light misfire on #8 cylinder. Swapped positions plugs (#7.#8); no change. Restored plugs, swapped coils; no change. Wiggled the fuel injector and problem went away. Maybe just a small leak. at the o-ring...
Root cause?
1. Hypothesis #1: Since the #8 cylinder seemed to have early warning sign, perhaps the valve was bent slightly when popping off this rocker (along with intakes on #5) to relieve stress on the cam for the phaser and timing chain replacement. This seems like the most likely suspect.
2. Hypothesis #2: Something happened to the intake manifold charge plate for #8 (e.g. came loose, dropped a screw). No damage or scratches noted on the spark plug. I do not have a bore scope and even with a mirror, I can't really see down in the cylinder.
3. Hypothesis #3: Serpentine belt break caused some issue with timing when it knocked off the cam position sensor. Seems like more than one valve would have been affected.
At this point, it is clear that the head needs to be removed and the cylinder inspected.
Some questions:
1. Any other ideas here on what happened?
2. Assuming the head and piston are basically ok, is it cheaper to buy a a refurb head or get it done locally?
3. If anyone has purchased a refurb head, any recommended source for quality and good price? I see Rock Auto has them.
4. Anyone have experience with new heads without doing anything on the bottom end? Vehicle has 182k, but has always been well maintained and is near mint condition. No plan to sell. I am hesitant to do a compression check on the other cylinders with the bent valve situation. when I did the oil pan gasket, I checked out the crank and didn't see any issues with freeplay or wear.
5. What about just replacing the valve, guide, and seal? Kind of seems silly not to do all.
6. What are the (mechanical) risks of only doing one head? Not trying to cheap out, just trying to work out the budget and the time.
7. Do in car or pull engine?
8. Bag it all and buy another engine? New heads and associated parts (no labor) ~$1200. Seems I can pick up a used one with low miles for ~$1000-$1500. Might cheaper from wrecking yard. Value of vehicle ~9k, but it has sentimental value (I can hear the laughter now...), so no plan to sell.
Thanks for any and all input.
