Timing chain stretch: '07 4Runner

[waypoint]

Taking a break from my timing chain replacement to post pics showing the elongation of the factory chain versus new Toyota replacement part. It's a 2007 Limited, 172K miles, chronic P0016 error code but ran fine. Original owner put 164K miles on it, changing the oil at approximately 20-30K mile intervals (stupid). Minor sludge on the valve covers and timing cover, etc.

This project is a PITA in terms of the number of bolts, accessories to remove, and gasket surfaces to be cleaned. Two kinds of magic Toyota form-in-place-gasket sealant to buy...one for the main timing cover surfaces, and one for the water pump passage surfaces. Oil pump O-ring in an awkward place during reassembly, if you don't drop the front diff and oil pan.

The good news is that I've found other future problems easily fixed while I'm in there: leaky radiator end tanks, alternator smells burnt, and two idler pulleys have worn-out bearings.

 

[Johns06yota]

Taking a break from my timing chain replacement to post pics showing the elongation of the factory chain versus new Toyota replacement part. It's a 2007 Limited, 172K miles, chronic P0016 error code but ran fine. Original owner put 164K miles on it, changing the oil at approximately 20-30K mile intervals (stupid). Minor sludge on the valve covers and timing cover, etc.

This project is a PITA in terms of the number of bolts, accessories to remove, and gasket surfaces to be cleaned. Two kinds of magic Toyota form-in-place-gasket sealant to buy...one for the main timing cover surfaces, and one for the water pump passage surfaces. Oil pump O-ring in an awkward place during reassembly, if you don't drop the front diff and oil pan.

The good news is that I've found other future problems easily fixed while I'm in there: leaky radiator end tanks, alternator smells burnt, and two idler pulleys have worn-out bearings.

Wow that was stretched pretty bad. And oil changes that far apart is crazy even if the dude was running full synthetic. It seems you know what to do but heres a video on the full replacement if it helps.

https://www.youtube.com/watch?v=UR50da0sDOc

 

[Tkblazer]

Man I don’t feel as pissed after getting a $3500 quote for that job. I don’t have any cel lights or errors, but wanted to possibly get the water pump, belts and tensioners replaces along with a coolant flush. The shop said I’m getting close to needing the timing chain replaced which I never heard needing to be done. My truck has 166k on it and had the oil changes done every 4-5k since new.

 

[waypoint]

Wow that was stretched pretty bad. And oil changes that far apart is crazy even if the dude was running full synthetic. It seems you know what to do but heres a video on the full replacement if it helps.

https://www.youtube.com/watch?v=UR50da0sDOc

It's a useful video and I've watched it several times. However, he left out quite a few steps in the video, and made it unnecessarily hard to install the main chain. Shop manual procedure looks much easier...idler sprocket goes on after the chain is hung and timing marks verified...then the tensioner. I'll be installing mine this weekend so we'll see how this works out.

Knowing now that my "engine noise" was actually two serpentine belt idler pulleys, and that my main chain tensioner still had 4-5 teeth on the plunger length, I think I could have delayed or avoided this project by simply advancing the bank 1 intake cam by 1 tooth on the chain as a guy on the FJ Cruiser forum did. Bank 2 timing was retarded slightly also, but not throwing a code. I'll never know, but for anybody else encountering P0016 with a stretched main chain I'd recommend experimenting with this before disassembling the front of the engine.

 

[waypoint]

Update: Update: the timing cover is on, what a PITA that was. Two o-rings and a bead of FIPG along the entire timing cover, plus a different FIPG at the water pump passages. I used Permatex "aviation" sealant to hold the oil pump pickup o-ring in place, very light coat on the pickup side and light coat on the o-ring side facing it, let them tack up, then put the o-ring on with light pressure until the sealant cured. I put a light film of motor oil on the oil pan pickup surface to let the o-ring slide across during timing cover installation. Hopefully it worked, fingers crossed.

I have the balancer and serpentine belt tensioner torqued to spec, next are the AC compressor, alternator, PS pump, and pulleys. Going very slowly and following the service manual to the letter. Should be able to spend time over the 4th of July long weekend and get it finished.

 

[Jj51702]

Wow

How did u find out the owner did 20-30k oil changes? Did they at least use a synthetic with a quality filter? I’d think it would be caked with sludge

Does ur engine consume any oil now over ur oil change interval and if so how much?

 

[waypoint]

Wow

How did u find out the owner did 20-30k oil changes? Did they at least use a synthetic with a quality filter? I’d think it would be caked with sludge

Does ur engine consume any oil now over ur oil change interval and if so how much?

Carfax and Toyota online records based on the VIN. Aside from the chronic P0016 error code, the engine had no other issues...no noticeable oil consumption, only minor sludge under the valve covers, got 21-23 MPG on the highway. Still had the factory NGK & Denso spark plugs with huge gaps when I changed them, ran fine.

 

[MrSeth]

Wow!!! I didn't know chains could sag THAT much. I bet she feels a bit more peppy, that looks like it could throw you a degree or two advanced or retarded when its hot!

 

[waypoint]

Wow!!! I didn't know chains could sag THAT much. I bet she feels a bit more peppy, that looks like it could throw you a degree or two advanced or retarded when its hot!

With bank 1 intake cam sprocket indexed on the zero mark, the crank balancer timing mark was approximately 10 degrees after top dead center (retarded).

The VVTi system was making up for the stretch well enough to keep the CE light out most of the time, so I'm not expecting to see much improvement. Still can't wait to see how it runs with the new timing components and all 5 sprockets now on the zero marks.

While I was in there, I found 2 serp belt idler pulleys with shot bearings and a leaky radiator. Good opportunity to catch-up the preventive maintenance.

 

[techno]

Thanks for posting with your experience. I'm getting ready/ psyching myself up for this job soon. I had P0016 all winter but it vanished when the weather warmed up in March, but then reappeared last week. How long has it taken you so far?

 

[radlynx]

I am at 130000 miles. is this the range when people gets this error and replace the chain?

 

[waypoint]

I am at 130000 miles. is this the range when people gets this error and replace the chain?

What year is yours?

94K miles was where the original owner brought it to the dealer for the CE light and was quoted an engine replacement. I bought it with ~164K miles, when he couldn't get it through inspection:

CUSTOMER STATES THAT THE ""MALFUNCTION INDICATOR LIGHT"" IS ON. (CHECK ENGINE LI ~|~CUSTOMER STATES THAT THE ""MALFUNCTION INDICATOR LIGHT"" IS ON. (CHECK ENGINE LIGHT) ~|~ ~|~94967 CODE P0016. TECH INSPECTED AND FOUND ENGINE SLUDGE THROUGHOUT CAUSING MIL. CUST WAS GIVEN ENGINE REPLACEMENT OPTIONS​

 

[waypoint]

Thanks for posting with your experience. I'm getting ready/ psyching myself up for this job soon. I had P0016 all winter but it vanished when the weather warmed up in March, but then reappeared last week. How long has it taken you so far?

It's my first DOHC engine project, so I'm following the service manual and moving slowly.

Disassembly: took me 1-1/2 days: radiator, intake manifold, valve covers, alternator, PS pump, AC compressor, alternator, water pump, pulleys, balancer, and timing cover. Soaked all the bolts in Kroil penetrating oil, all came out without drama. Ziploc bags and Sharpie marker labels for all the bolts.

For reassembly, I'd estimate 3 solid days thus far and 1 more to go. Probably spent more time cleaning bolt threads, cleaning hole threads, cleaning the timing cover and block surfaces than the actual chain replacement.

This past weekend I reinstalled the timing cover (major PITA), water pump, balancer, PS pump, belt tensioner assembly, valve covers, ignition coils, and AC compressor. About 6 hours on Saturday, another 2 on Sunday. I'm tightening every bolt to spec with a torque wrench, in sequence and in steps where the shop manual specifies e.g. timing cover, AC compressor. Adds a lot of time, but the whole thing is aluminum which is generally not tolerant of variation in fastener tightening.

All that's left are the alternator, intake manifold, thermostat housing, water pump pulley & fan, radiator, and wiring harness connections. Probably not a whole day if all goes well.

The two oil system o-rings are a cross-fingers ordeal, hoping they stay in place while the timing cover goes on. The small one on the block has nubs molded in to hold it in place, but the large one at the bottom of the timing cover does not...and it could really use them given the location. I used Permatex "aviation" sealant to hold it in place, but I'll still be watching the oil pressure light and crossing my fingers during that first startup. If either o-ring popped out during assembly, it's another complete teardown.

 

[Jj51702]

Carfax and Toyota online records based on the VIN. Aside from the chronic P0016 error code, the engine had no other issues...no noticeable oil consumption, only minor sludge under the valve covers, got 21-23 MPG on the highway. Still had the factory NGK & Denso spark plugs with huge gaps when I changed them, ran fine.

Wow, factory copper plugs with 164k? I was planning on stretching my spark plug change interval to 50k because every 30k seems like a pita. How often do I plan on changing ur plugs?

 

[waypoint]

Wow, factory copper plugs with 164k? I was planning on stretching my spark plug change interval to 50k because every 30k seems like a pita. How often do I plan on changing ur plugs?

30-40K miles with NGK stock replacements, whenever it's not too cold or hot in the garage.

 

[radlynx]

I have the 2005 v6 sr5 model. I am now at 135000 miles, not 130. so far I don't have a problem with it. I hope I could go beyond that.

What year is yours?

94K miles was where the original owner brought it to the dealer for the CE light and was quoted an engine replacement. I bought it with ~164K miles, when he couldn't get it through inspection:

CUSTOMER STATES THAT THE ""MALFUNCTION INDICATOR LIGHT"" IS ON. (CHECK ENGINE LI ~|~CUSTOMER STATES THAT THE ""MALFUNCTION INDICATOR LIGHT"" IS ON. (CHECK ENGINE LIGHT) ~|~ ~|~94967 CODE P0016. TECH INSPECTED AND FOUND ENGINE SLUDGE THROUGHOUT CAUSING MIL. CUST WAS GIVEN ENGINE REPLACEMENT OPTIONS​

 

[waypoint]

I have the 2005 v6 sr5 model. I am now at 135000 miles, not 130. so far I don't have a problem with it. I hope I could go beyond that.

The timing chain elongation issue seems most frequent in the 2007 4Runner and FJ Cruiser family, based on my research...it's possible they got a marginal batch of chains that year but it's just a theory.

I've seen pics of massively sludged earlier 4Runners, but the #1 chain tensioner piston was not overextended on any of them. You should be fine if you keep your oil changed as the manual specifies.

 

[waypoint]

Update on my chain project: it's back together, just finished a 120 mile test drive. Whatever the shops charge to do this job, they're earning that money. A lot of time and wrenching getting the engine undressed and re-dressed correctly.

No visible leaks, no error codes of any kind, long term fuel trims are finally balanced (bank 1 was averaging 3 points variation relative to bank 2 across the board previously). I can't say it runs any better or differently than it did w/ the worn out chain, other than during cranking. Hard to describe the sound difference, but the starter seems to be spinning at a more uniform rate now whereas before the speed & sound seemed to oscillate. Probably more uniform compression now that the cams are timed correctly on both banks.

In addition to the chains and kit, I also replaced the serpentine belt idler pulleys, alternator, radiator, and main hoses. Also removed and cleaned the carbon out of the throttle body with a toothbrush and throttle body cleaner spray. One more $3 gasket but the TB was cruddy and needed it.

 

[D. Le]

You should've changed that head gasket and clean the heads. You're almost there, haha.

 

[waypoint]

You should've changed that head gasket and clean the heads. You're almost there, haha.

Just one head gasket, not both?

That would be a stretch for a "while I'm in here" scope creep. It's an '07 which was built with the improved multilayer steel head gaskets, they seem to have addressed the blowout problem.