P0016 error on 2006 Prius 70,000miles - is it hard to DIY replace the timing chain?

Read the service manual- several times- watch youtube- until you understand all the steps. The big thing is if you make a mistake, some valves could be open at the wrong time and hit the pistons.

Scrapers, razor blade, whatever works. Don't damage the sealing surfaces, and keep debris out of the engine and oil pan.

Remove the valve cover and the old gasket will likely leak.

There's a skinny spring "inside" the lip of the crank seal. You don't want to knock that spring out of position when installing it in the cover. Apply oil or petroleum jelly to the lip and crankshaft sealing surface. Be sure the lip isn't torn or "folded" when it goes onto the crankshaft.

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I did this several years ago in one of my Prius, same code P0016. A failing chain tensioner can also caused this issue, in my case it's both. If I remember it's not that difficult compared to other cars, I didn't use any special tools. I just marked the sprockets and chain and transfer that marks to the new chain. This approach is a foolproof way to align the timing (of course it has to be TDC) since the VVT gear freely moves when you wrap around the chain. The marks make sure that they are in-sync. The stretch on my chain is not that bad but Toyota could be sensitive on such discrepancy. You need to buy the Toyota tri-bond gasket (it's the best gasket that I've used so far) and use it to seal the timing and valve cover, also best time to replace the pcv. It took me almost a day as DIY to finish everything. Also it requires draining the coolant since the water pump is removed. No need to drain the oil. I didn't replace the sprocket, just the tensioner and chain. You might replace the valve cover gasket too just in case, in my case I have to re-use the original since the one I purchased didn't fit correctly (it leaked oil) buy Fel-pro or OEM.

The kit you are trying to buy is junk, get the Cloyes kit. You don't need the sprockets and VVT gear (you'll get a different code for VVT failure)

here's the kit I used, I didn't use the sprocket.
More Information for CLOYES 94214SA




https://youtube.com/shorts/4uf4HYqcH7c

 

Yep, @ 70K miles it's more likely some nylon busted-off those chain tension blocks. The four cylinder GM products are notorious for this. I doubt there's much stretch in your chain - but since your in there. You should do the job correctly. There isn't a need to change the sprockets, unless you observe damage or heavy wear, and make sure the VVT gear moves freely.

 

Have you owned this vehicle since new?

Have you been step by step through the workup for DTC P0016 (below)?

https://attachments.priuschat.com/attachment-files/2018/04/144690_VVT.pdf

 

While the "timing" is a thing you can check, it isn't a thing you can replace. They aren't using the word "timing" to mean "timing chain". They mean for you to check whether the camshafts are turning in proper time to the crankshaft.

You can check that by having just the cover off, and seeing whether you get the match marks on the crank and camshafts at the right places at the same time. (They won't match the painted chain links every time around; that's normal. In a Gen 3 it's every ninth time around for the chain, but I don't know the number for Gen 2. You can ignore the painted chain links as long as you're positive about the positions of the timing marks on the sprockets.)

"If I'm already there might as well go all the way" is dubious for this job: the labor of taking just the valve cover off is nothing like the "all the way" job.

They only suggest replacing the chain if you actually find the timing mark alignment not OK. Otherwise they suggest replacing the ECM.

 

Yes, you do have to do both of those things. (Or reuse the gasket if it's ok, as highmilesgarage did in #22, but the new sealant is a good idea.)

So now compare that to draining the coolant, supporting the engine, removing the engine mount, oil filter bracket, thermostat, and water pump, the tensioner and timing cover, slippers and chain, and reassembling, with the 15 specifications for where the FIPG sealant goes, the three minutes you have to do it and get the cover back in place (without bumping or contaminating the FIPG), the ten minutes from FIPG application you get to have the oil filter bracket and engine mount back in place, and 15 minutes from application that you get to have all 23 bolts and nuts properly torqued. You can't bump the engine or the cover with the blob of grease on your wrist while sneaking your arm down where you can't see, or you have to clean it all off and start over. If you don't have the cover correctly positioned and secured, without false starts or sliding, in the right number of minutes, from when you start squeezing the tube ... you clean it all off and start over.

It's a job many would leave well enough alone unless there is clear evidence showing it needs to be done.