Blown Head Gasket with no warning

I have a 2014 Tundra SR5 5.7L with 149,00 on it. I was about to go on a 120 mile road trip while towing a trailer so I decided to top off my coolant. It wasn’t under the minimum line but I wanted to add some. Didn’t add much. I got to my destination where I camped for 3 days. The truck ran perfectly fine. When I was about to leave I fired the truck up and seen that the check engine light was on and the dash read “Traction Control Off” I did not have a scanner or anything with me so I headed for home. Truck ran perfectly. Next day I drove the truck 2 miles across town and it was not running good at all. I would hit about 35 MPH and it would start shaking like crazy. Got home and scanned it. P0308 aka misfire on cylinder 8. Went and got an ignition coil and spark plug. Replaced them and fired it up. CEL was gone so I went to put my tools away in my garage. I turn around and my garage is filled with white smoke. I Scan it again and now it says misfire on 2,3,5,7, and 8. Back pressure in the coolant system and I did a leak combustion test and it came back positive for combustion gasses in the coolant. I did not over heat the truck and have no idea what could’ve caused this. Any help would be appreciated

 

How many miles on the truck, and how often do you change coolant?

 

In addition to the two above questions - how was the truck used? For example - daily driver, highway, towing, etc.

Any lift? Tires?

 

Bought it with 132,00 and it is at 149,00. I haven’t flushed it yet I’ve only been adding

 

it is my daily driver and I tow a lot. Not everyday but more than your average guy. No lift but had 35s on it

 

That’s a bummer. I’m assuming stock gears? Anything in the service history re coolant changed?

I feel for you as I’m on 35s and tow frequently. 110k on mine - but I did dump the coolant at 60k and am about to do it again.

 

Yeah I’m in a bad situation right now. Trying to figure out the best route to go. Might do it myself but want to figure out why it happened before I fix it.

 

I’m guessing you’ve done some research - going for repair is dicey. There is a significant chance the block is damaged making irreparable.

 

How could the block be damaged? I would assume the head before the block would get damaged

 

Being aluminum engine block and cylinder heads, it's possible both could be warped, or just a blown head gasket....It would have to be disassembled and checked. ,

 

Even though I didn’t over heat the truck you still think they could be warped?

 

It’s not about overheating - it’s the pressure from the explosions that are supposed to be contained within the cylinder escaping and damaging the surfaces.

 

Only adding? For how long? Hopefully you didn't buy someone else's blown head gasket.

 

If it hasn’t overheated then there’s a good chance nothing is warped. The only way to tell is if you pull the head and use a straight edge on it. Maybe the previous owner abused it? Buying used is always a gamble.

 

My guess is the antifreeze was never changed out and it became corrosive and ate the head gasket.

Also, 99% chance the heads and block are fine. You can pull the heads and check them and the block for straightness.

 

Welcome to the club. Just noticed mine started leaking a couple weeks ago. I didn't have a misfire though. I have a 2014 with 196k miles.

I put a video out on youtube the other day, but I ran some Blue Devil head gasket sealer (the yellow bottle, not the pour-n-go) last week. Seems to be holding thus far. Put about 100 miles on it since then and coolant levels are unchanged. I plan on running a hydrocarbon test on the coolant after driving it for a few days. We'll see how long it lasts. I have heard some people getting YEARS out of their engines after using Blue Devil.

Everyone I have spoken with says you need to pull the engine out of the truck to do the headgasket job because it's a PITA to do it in the truck and if the block is warped at all, you're F'ed.

I got some quotes from the dealer & Independent shops.

My local dealer quoted me $17k for tear down and rebuild of the existing engine. That include replacing basically everything in the head since all the components in mine have 200k miles and probably a good idea to replace them with new. Doing the timing chain, starter, etc. All the things to tackle when the engine is out. That also includes sending the heads & block off to a machine shop that will measure tolerances & machining of surfaces if necessary.

My Dealer also quoted me on replacing the engine with a Remanufactured engine (Jarco engine) with warranty. That was $16k. 5-7 week lead time.

My dealer will not swap in a used engine.

I also called two well rated independent Toyota/Lexus Shops in my area:

First shop quoted $11k for tear down and rebuild (Assuming heads & block are ok). Machining would be additional.
They also quoted around $11k for a used engine with 1 year warranty.

Second shop Quoted $14k for tear down and rebuild, not including machining. Machining would be another $1k.
They also quoted $11,500 to swap with a used replacement engine with a 1 year warranty. $6,500 for the engine, $6k in labor.


I went ahead and bought a lower mileage used replacement engine for it off Ebay. Go Checkout OK Auto parts in MS on Ebay. They do fantastic writeups and photos of the engines they sell. Provide the VIN number & pictures of the truck the engine came out of. I bought one with 76k miles out of a 2018 and the Service history on the VIN through Toyota owners.com was all done at the dealer at regular intervals. Engine arrived Friday and it's in great shape. Engine harness is 100% intact. The only thing it's missing is the plastic engine cover, and the passenger side exhaust manifold heat shield. I bought that engine for $5,500 with Freight shipping. It's sitting in my basement ready to go waiting on whenever the Blue Devil lets go... Then I'll swap it.