2011 Prius Head Gasket Failure at 185k - Summary

Joined
Aug 30, 2004
Messages
25,602
Location
CA
You may have seen the recently-posted photos of the valvetrain and the cylinder head from my 2011 Prius. I am starting this thread to summarize what happened. - On the afternoon of 2/24, I observed a loud knock from the engine bay during start-up. The knock lasted several seconds. After the engine started, I also noticed stumbling for several seconds. - The next morning, 2/25, I observed the same loud knock from the engine bay during start-up. Except this time, the Check Engine Light came on. The car was scanned and I found a current P0302, as well as various pending and historical fault codes for P0302, P0300 and P0304. - Later in the afternoon, the knock happened again when I started the car to leave work. The coolant level was also 2" lower than where it previously was. At this point, I decided to stop driving the car until I had time to confirm and correct the issue. After the car was parked for two days, I removed the spark plug from cylinder #2 and performed an inspection using an inspection camera. The top of the piston was wet with liquid (coolant). For comparison, I inspected cyl #3 and it was dry. Headgasket issues are common on the Toyota 1.8L 2ZR-FE (2009+ Corolla) and 2ZR-FXE (2010-15 Prius) at high mileage. Based on my visual inspection, I decided to proceed with disassembling the engine. The game plan was to replace the headgasket (and any gaskets which were removed during the repair), resurface the cylinder head and replace the intake VVT camshaft gear (due to rattling). I am the original owner of this car. At the time of failure, the vehicle had 184,997 miles. Engine coolant had been replaced at 30K, 90K, 122K and 179K. Thermostat was replaced at 122K with a dealer unit. Engine Water Pump was replaced with an Aisin at 179K for maintenance; there were no issues. The EGR cooler and valve were cleaned at 179K (valve and pipe were cleaned once previously at 160K) and they never showed any signs of blockage. Spark Plugs had been replaced at 92k and at 179K. Here are some photos of the repair process: Cylinder Head Removed: [Linked Image] Photo of the Engine Bay with the Cylinder Head Removed: [Linked Image] Photo of the Camshaft Housing and Cylinder Head Removed. Yes, I am aware that I was missing one valve stem cap: [Linked Image] My finger is pointed to the location of the head bolt that was looser than all of the other ones. Coincidentally, this is also the area where the headgasket may have failed. During reassembly, all head bolts were able to be torqued to spec w/o issue, so I am not sure why this bolt was loose: [Linked Image] Cylinder Head after the machine shop did their work. The cylinder head was NOT warped. The shop resurfaced the head (.003" removed) to a 20rA finish, cleaned the head, did a full inspection and install the new valve stem seals I provided: [Linked Image] Timing Cover all cleaned and ready for fresh FIPG (RTV). CRC Gasket Remover, plastic razor blades and light use of a fine wire brush was used for cleaning: [Linked Image] Photo of the front of the engine. All cleaned: [Linked Image] Cylinder Head cleaned and exhaust manifold re-installed with a new gasket: [Linked Image] Cylinder Head, Camshaft Housing and Timing Cover re-installed. nthach came by and assisted; it was a lot easier to install a cylinder head w/exhaust manifold and timing cover with two people: [Linked Image] All done: [Linked Image] In total, I spent between 11-12 hours over the course of several days. Overall, it was not a bad job at all. There are some tricky parts to the repair, but nothing that is not DIY-able. A local dealer quoted me $4200 and a nationally-recognized hybrid specialist quoted $4800 (more if the connecting rods were bent, which is supposedly common). Book time for the job is 18-ish hours w/Engine Removal. The labor rates on the West Coast are quite high ($160/hr+) and it often not economically feasible to repair high-mileage vehicles. I ended up spending $889.85 on the parts and the machine shop work. Here is what I installed: 1) Engine Overhaul Gasket Kit - Genuine Toyota (part # 04111-37315). I used every gasket in this kit except the Rear Main Seal. This kit is awesome; it includes EVERY seal on the engine....even the dipstick tube seal and the oil cap seal. 2) Head Bolts - Genuine Toyota 3) Thermostat - Genuine Toyota 4) FIPG Black, 2 tubes - Genuine Toyota 5) Camshaft Timing Gear Assembly - Genuine Toyota (part# 13050-0T050). These have been problematic on the 2ZR-FE, not so much on the 2ZR-FXE for some reason. But I decided to install the latest revision since mine rattled occasionally. 6) 2 gals of CCI/GC Super Long Life Pink Premixed Coolant 7) Spark Plugs - Denso #3499 8) SuperTech 0w20 Dexos Synthetic and Genuine Toyota Oil Filter. Note: for the initial start-up, I filled the engine with a mix of various leftover 5w20 and 5w30 synthetic oils and a new filter. I drained this mix after the engine idled for about an hour, then the SuperTech 0w20 was installed. If you own a Toyota 1.8L with the 2ZR-FE or 2ZR-FXE, beware. There is a very good chance that you will have to do this job sometime, and if you have to pay someone, it will likely exceed the value of the car. So, I would definitely consider doing the job yourself if the engine does not burn any oil and you have not driven very much since the failure starts.
 
Last edited:
Joined
Oct 13, 2008
Messages
15,001
Location
The Old North State
I had to have a head gasket replaced on a 2001 Civic EX at ~165k miles, pretty normal occurrence for them. Dealer replacement charge, ~$600. With $4200-4800 quotes, for average individual safe to say imo HG replacement would present serious vehicle trade/sale consideration for most. Good that you have the availability of resources along with skill to diy.
 
Joined
May 30, 2010
Messages
14,254
Location
North Carolina
Were those TTY bolts originally? Maybe one did not get torqued right at the factory. Or could be some reason those bolts stretch more there, if its a common prius problem.
 
Joined
Oct 3, 2010
Messages
2,099
Location
RI
Good work. If you look there is a clean break in the sealant from the fire ring right into the water jacket on the gasket. Without a doubt that loose bolt was a contributing factor
 
Joined
Jun 30, 2018
Messages
324
Location
TX
Good work. How do you check for bent rods without getting to them? It seems the takeaway would be to re-torque the head bolts at some interval. The older Supras and others (late 80's) had HG failures, supposedly due to the removal of asbestos from the gaskets. Happened to my 89. 94 was ok tho.

Supra at dusk.jpg


Supra left side.jpg
 
Joined
Jun 15, 2003
Messages
37,242
Location
ME
Originally Posted by spasm3
Were those TTY bolts originally? Maybe one did not get torqued right at the factory. Or could be some reason those bolts stretch more there, if its a common prius problem.
Most makers are *extremely* good at repeatably torquing things to spec at the factory. But if there was some unknown issue like the gasket collapsing over time, it would make the bolt in effect be looser. Your theory of that bolt stretching is as plausible as anything. I'm sad the 1.8 prii aren't following the rep of the 1.5s. Be nice to upgrade in time to something newer. Good write up, OP.
 
Joined
Apr 24, 2018
Messages
1,914
Location
Wisconsin
General consensus is you need to clean the egr often and have a catch can, proper cool down of the engine before shutdown is important as well. It is worth noting Most who have replaced a head gasket have had to do it again not long after, it's not uncommon for the 2nd gasket to last a much shorter time than the first. Good Luck
 

The Critic

Thread starter
Joined
Aug 30, 2004
Messages
25,602
Location
CA
Originally Posted by Rmay635703
It is worth noting Most who have replaced a head gasket have had to do it again not long after, it's not uncommon for the 2nd gasket to last a much shorter time than the first. Good Luck
Why do you think that happens?
 

The Critic

Thread starter
Joined
Aug 30, 2004
Messages
25,602
Location
CA
Originally Posted by eljefino
Originally Posted by spasm3
Were those TTY bolts originally? Maybe one did not get torqued right at the factory. Or could be some reason those bolts stretch more there, if its a common prius problem.
Most makers are *extremely* good at repeatably torquing things to spec at the factory. But if there was some unknown issue like the gasket collapsing over time, it would make the bolt in effect be looser. Your theory of that bolt stretching is as plausible as anything. I'm sad the 1.8 prii aren't following the rep of the 1.5s. Be nice to upgrade in time to something newer. Good write up, OP.
Yes, they were torque to yield bolts. 36 ft lbs + 90 deg + 45 deg is the torque spec.
 

OVERKILL

$100 Site Donor 2021
Joined
Apr 28, 2008
Messages
48,427
Location
Ontario, Canada
Originally Posted by The Critic
Originally Posted by eljefino
Originally Posted by spasm3
Were those TTY bolts originally? Maybe one did not get torqued right at the factory. Or could be some reason those bolts stretch more there, if its a common prius problem.
Most makers are *extremely* good at repeatably torquing things to spec at the factory. But if there was some unknown issue like the gasket collapsing over time, it would make the bolt in effect be looser. Your theory of that bolt stretching is as plausible as anything. I'm sad the 1.8 prii aren't following the rep of the 1.5s. Be nice to upgrade in time to something newer. Good write up, OP.
Yes, they were torque to yield bolts. 36 ft lbs + 90 deg + 45 deg is the torque spec.
I wonder if ARP makes a head stud for these?
 
Top