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.

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.

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.

Some project notes for anybody else undertaking a timing chain replacement, with the caveat that this is for informational purposes only and should not be taken as authoritative:

-I soaked the new chains in clean motor oil prior to mounting them, to allow oil to soak into the pins & bushings. Also applied a light coat of engine assembly grease to the sprocket teeth, guide rails, and tensioner sliders as prelube. No dry new parts during initial startup.

-I removed the two threaded studs from the block at the lower side of the timing cover to allow more up/down movement of the cover during installation. They threaded back into the block easily after the cover was in place.

-Triple-check the oil pump drive alignment *before* applying FIPG to the timing cover. The service manual provides a drawing showing the oil pump center gear at about 1 o'clock, with the crank at #1 TDC.

-Do a few dry runs installing the timing cover without sealant and before the oil pump o-ring is installed. Build muscle memory for the process, it's a complex operation getting the oil pump, pickup o-ring, FIPG bead, and block dowels aligned in one smooth motion.

-I also left the crank seal out during timing cover installation, to allow more up/down movement of the cover. The new seal drove in easily after the cover was bolted up...seal drives in until flush with the timing cover surface, no more and no less. Leaving the seal out also allows for visual inspection of the oil pump center gear and drive, and wiggling the oil pump center gear to get it aligned during assembly if needed.

-The timing cover was most easily installed by placing the bottom of the cover onto the oil pan surface first, at a slight angle with the top of the cover away from the engine, and then tilting the cover onto the engine while gently pushing the lower cover onto the oil pump drive and the 2 block dowel pins. Again, do a few dry runs before installing the o-rings and applying FIPG sealant.

-Permatex "aviation" sealant did a nice job of holding the oil pump o-ring in place during timing cover installation. Light coat in the o-ring groove, light coat on one side of the o-ring, let both tack up for ~5 minutes, then press the o-ring into place. I used a large plastic carpenter's clamp and a plastic spatula-type scraper to apply light & uniform pressure to the o-ring while the sealant cured.

-Light coat of motor oil on the o-ring and oil pan surface it seals allows the o-ring to slide across smoothly during timing cover installation.

-The shop manual calls for removing the oil pan for this, I didn't. After the cover was in place and a few front bolts loosely threaded, I torqued the 4 bolts attaching the oil pan front to the timing cover bottom first. Goal was to compress the oil pump o-ring and ensure sealing. First pass at 7 N*m, then second pass at 14 N*m then final pass at 23 N*m. Then I torqued the front bolts in same 3 steps, starting at the center and doing figure-8 sequence outward. It's a lot of work doing all the bolts 3x gradually, but the thing's aluminum and avoiding warpage is worth the effort.

-FIPG sealant: The shop manual calls for 2 different FIPGs: one for the water pump passages, and a different one for the cover's main sealing surfaces. I used the Toyota specified expensive FIPG for the water pump surfaces, not sure if this was absolutely necessary but it wasn't worth risking re-doing the project to save $40. The #103 FIPG specified for the cover's main sealing surface was only $15 at the dealership, but the $40 water pump passage FIPG was special order.

-Prior to initial startup of the engine, I removed the fuel pump fuse and used the starter to build oil pressure until the oil pressure warning light went out. Three short cranks of a few seconds each was all it took, and probably helped pressurize the new #2 chain tensioners which don't have ratchets like the #1 chain tensioner. When I reinstalled the fuel pump fuse and started the engine, it was quiet.

Wondering how things went on start up? Success?

I'm just over 1,100 miles since the reassembly and all is well. Runs much more smoothly under acceleration than it did with the stretched chain, long term fuel trims are reporting within 0.78% of each other on both banks now (were showing ~3% variation between banks), dash showed 24.x MPG on the most recent road trip with the cruise set at 70mph.

I debated replacing the oil pump while I was in there, but the oil warning light had always gone out during cranking right as the engine started so I left well enough alone. Light still goes out before I take my hand off the key, so all is well.

In all, it was a good outcome having bought the Runner for cheap as a project. The timing cover was a royal PITA to clean and reinstall...aligning the oil pump drive and 2 block dowel pins while not smearing the bead of FIPG or unseating the 2 oil o-rings is a delicate process. Following the shop manual step by step is an easy win.

When I asked the my local Toyota dealer about the seal packing, the parts guy said they use #103 FIPG for everything. I like your idea of actually using the correct sealant for the water pump part.

Was the sealant you bought part number 08826-00100 or do they have a newer number for it? Also, where did you buy it? I use Boch Toyota South for cheaper online Toyota parts, but they have that listed as $62 right now.

Thanks.

It was part# 08826-00100.

Gotta give you props for this, man. Thanks for all the details, and hats off for a difficult job done well.

Just wanted to say that I bought a 1988 4Runner new (22R-E), and somewhere around 150k it developed a slight rattle which my service guy told me was a worn timing chain guide. He didn’t seem concerned about it and just told me to keep up with oil changes.

I drove that thing to 305k, doing regular oil changes, and never did anything to the chain. So when you say maybe you could have avoided it, perhaps you were right. But now you have bragging rights over the rest of us!

Again, excellent job. Thanks for sharing!

fuuuuuuuck that!

What is the spec for the 4 cam sprocket bolts?

100 N*m as shown in the shop manual posted here: https://www.customtacos.com/tech.old...6ta/003000.pdf

You'll become familiar w/ the shop manual during this project.

No excuse for neglecting oil changes, but it does show that chains aren't what they are cracked up to be. Is a serviceable belt such a burden?