2010 Prius still shakes after head gasket job and EGR + intake cleaning

Hello,

My 2010 Prius had a blown head gasket with the typical symptoms of rough shaking, white smoke, and low coolant levels. I went ahead and did the job myself and followed a lot of the suggestions from this forum. I made sure to check for warpage, valve leaks, piston/rod condition, replaced water pump, replaced thermostat, replaced PVC valve, and replaced all required gaskets with OEM.

The car ran smooth at first with the symptoms clearing up. I took it on a test drive for about 5 miles before I started to notice some minor shaking coming from the front.

I assumed it was probably the EGR and intake causing it because I only cleaned them a briefly, so I took the intake & EGR out to thoroughly clean them. This time around I cleaned them until there was no carbon left in both components. I used oven degreaser for the EGR cooler, parts cleaner for the EGR valve, and purple power for the intake manifold.

I just put the intake and EGR back onto the car and now it shakes violently upon start up. I scanned for codes and saw nothing. I let the car run for about a minute to see if maybe it would clear up or perhaps a code would pop up eventually, but neither occurred. I had a local Toyota technician stop by my house to assess the car and he suggests the shaking is coming from the transmission. He says it's possibly a component within the transmission which might have come loose that's causing this shake. I'm not too familiar with the transmissions in the hybrid Toyotas, so I am in need of help with diagnosing the problem.

I am posting on this forum for possible leads/ second opinions on what could be the issue? What are some other diagnostic tests I should complete?

 

I inspected the head and block with a straight edge and feeler gauge multiple times before reinstalling. Not even 0.0015th of an inch (0.04mm) could fit between the straight edge and block/head. I thought it was good enough based on the information from the repair manual found on this forum (0.05mm being the maximum warpage). I didn't take it to the machine shop based on my assessment and I didn't want to risk having the head machined if it wasn't needed which could cause timing issues if the head was machined too much.

I doublechecked the timing and made sure to lock the cam with a folded towel before taking it off. The timing marks were lined up and I quadruple checked before putting the tensioner on.

I drove it no more than 5 miles before I parked it in my garage to redo the EGR and manifold cleaning since the small intermittent rattle/shake was bothering me.

Do you have the specific name of that damper so I can research it more?

Yes, I checked the head and block with a straight edge and feeler gauge. Not even 0.0015th of an inch or 0.04mm could fit between the straight edge & block/head. New headbolts and gasket from Felpro were used. I torqued them down to OEM specification with the right torque, pattern, and additional degrees.

I'll do a compression test with borescope today. Just need to find an autozone that'll have both ready to loan.

The first time I started the Prius after the head gasket it had the violent shake with some puffs of white smoke, but was expected and cleared up. The Prius idled smooth for about 10 minutes in maintenance mode before I decided to take it for a test drive. I drove it less than 5 miles before I noticed a minor shake that was less violent than the pre-head gasket. When I parked the car and let it idle after that I did notice there was a minor shake that was intermittent.

That was when I decided to pull it in my garage and worked on cleaning the EGR and intake manifold. It took me about 2 weeks of soaking and rinsing with a pressure washer to get all the carbon cleaned out. Started the car 2 days ago after assembling everything and now it's a violent shake like pre-headgasket that is continuous.

The Prius has 180K lifetime miles. I drove it for at most 5 miles after doing the headgasket job before parking it and haven't driven it since. At the end of the drive at maybe mile 4-5 I noticed the minor shaking which is when I decided to park and let it idle. I observed intermittent minor shaking that was a fraction of what the shaking was pre-headgasket. From then I decided not to drive it and did the EGR and intake cleaning which took about 2 weeks. There was only a delay in cleaning because there was so much build up and I needed to soak the parts and rinse them out numerous times.

Started the Prius up 2 days ago with all clean intake and EGR system and was met with a violent shake that was continuous. The shake was on a similiar level to pre-headgasket shaking.