Pretty sure head gasket is leaking

Wife’s truck 2006 TRDOR SCSB AT 167k miles (with a manufacturing date of 9-2005 which = non updated weak head gaskets) started stumbling on startup and threw the P0304 code. This happened after a slight overheating issue that happened after changing the thermostat and housing because it was leaking. The reservoir filled all the way up and spewed out but the temp gauge stayed halfway. Changed the fan clutch for peace of mind but as I read into things on here I was lead to look at a head gasket issue. Started truck in the morning, it was a very warm morning almost 80, and seen a bit of steam coming out the pipe until the stumbling stopped and the steam went away. Did a compression test and was good. Then found a thread on here where a guys says to pull all the plugs, pull EFI fuse, and fill the radiator to the brim, pinch off overflow line, and then put a spark plug back into each cylinder one at a time and crank it while watching to see if the radiator level rises to overflow. If it does then that indicates exhaust gasses entering the system from a compromised head gasket. So I pulled all the plugs and put the #4 plug back in first since it has the misfiring P0304 issue. Sure enough the radiator level slowly rises as my Pops cranked it until it was about to over flow. I also did the same with cylinder 3 and 6 to cross reference and the level would not rise while cranking on them. I am now gonna pressurize the cooling system and bore scope cylinder 4 just to look for coolant. I’m pretty sure the head gasket is leaking from the previous test but gonna scope it for more evidence. Starting this thread to help others with this issue. Also, I want to ask my Taco Brothers and Sisters what to do if my head gasket is blown? Buy a used 2007 and newer engine or rebuild what I got? I don’t have the tools or shop to do the work myself. Thanks

 

I'd go with a 2007-2011 low milage used engine.
Or pay a shop to do the head gaskets.
The cost will likely be about equal.

 

I’m a bit leery of a used engine because what if the previous owner never changed the oil? What should be included in a head gasket replacement? New Timing chains, guides, valve job etc? Thanks Dog!

 

No affiliation but maybe this could work?

https://www.tacomaworld.com/threads...ff-road-100k-frame-shot.862769/#post-30751807

 

The more important part is if the head is warped or not.
If it's not warped, I'd just throw it back on as is.
On rare occasions, the block can warp.
But any shop that does head work should know this stuff.

 

Thanks for looking out! That is on the other side of the country from me, I’m in NorCal. It’d cost 1k in gas just to drive it back but would definitely love to have a whole parts truck!

 

The leak is so slow that I’m leaving a coolant system pressurizer on there for a few hours and then checking for any coolant puddled up. The head gasket on the Before December 2005 manufactured trucks are all to common from what I’ve read. Do you really think the head could be warped? I’ve never had the temp gauge in the red in the last 10 years that we’ve owned it

 

Here’s a quote of the test I did-

“Fill It Up: Being fooled by chemical testing/infrared testing of the cooling system for head gasket failure(s), 1 stumbled on a better method, which is much faster and more accurate, too.

Next time, try this:

1. Remove all the spark plugs from the engine.
2. Fill the cooling system right to the rim of the radiator neck.
3. Disable the ignition system.
4. Insert one spark plug in a cylinder and then crank the engine for five to 10 seconds, while watching the radiator level. (A remote starter comes in real handy here.)
5. Repeat step 4 above for all cylinders.

The idea behind this is simple: This uses the engine's compression to pressurize the combustion chamber and force this pressure past any potential head gasket/cylinder head leakage into the cooling system. Should there be a leak, the level in the radiator will overflow. The reason all other spark plugs are left out is to allow the starter to spin the engine faster, without shaking so much and helps to identify which cylinder is the culprit. Why not let the 150 to 200 psi compression do the testing? Now, 13 to 15 psi in the radiator to test it just doesn't seem up to the job anymore, does it?

Brad Petersen, Owner, ASE L1 Master Tech, Peterson Automotive, Escondido, CA”

 

It's not likely that it is warped. But this is the internet.
As soon as I didn't mention it. Someone would quote me and "correct" me.
Saying, "That's not good advice. You need to check the head. It could be warped......"

I "usually" try to cover my bases when giving advice. (If you know what I mean?)

Straight edges are cheap. My local AutoZone sells them. (Less than $60)
So of course, I'd check the head. Why not?.....

Still, it's a toss up.
Used engine? or pull both heads?
I mean 167k isn't a lot of miles. So there is an argument to be made in your case for keeping your current engine.

It's really your call.

Is the frame of your truck in good shape?

 

I totally understand about covering your bases and mentioning potential warping. Yeah the frame is great thankfully. I did take it in for the frame check and the dealer said the frame has to be so bad you can poke your finger through it to qualify for the recall lol. It has very light surface rust so he said I don’t get a new one darn it.
I compression tested the driver side bank, and cyl 6 is @170, cylinder 4 (where the leak is) is @170, and cylinder 6 is @174. My buddy who’s an ASC tech said those numbers are good. He is super busy so I don’t think he can do the hg job for me. But there is a guy in the next town over w a shop that has done some good work on my mom’s Honda, might call him for a quote?

 

You can't rely on compressing numbers to diag a gasket.
Pressure testing the coolant system and looking into the cylinder is a far better diag. method.

 

Well it failed this test—-
“Fill It Up: Being fooled by chemical testing/infrared testing of the cooling system for head gasket failure(s), 1 stumbled on a better method, which is much faster and more accurate, too.

Next time, try this:

1. Remove all the spark plugs from the engine.
2. Fill the cooling system right to the rim of the radiator neck.
3. Disable the ignition system.
4. Insert one spark plug in a cylinder and then crank the engine for five to 10 seconds, while watching the radiator level. (A remote starter comes in real handy here.)
5. Repeat step 4 above for all cylinders.

The idea behind this is simple: This uses the engine's compression to pressurize the combustion chamber and force this pressure past any potential head gasket/cylinder head leakage into the cooling system. Should there be a leak, the level in the radiator will overflow. The reason all other spark plugs are left out is to allow the starter to spin the engine faster, without shaking so much and helps to identify which cylinder is the culprit. Why not let the 150 to 200 psi compression do the testing? Now, 13 to 15 psi in the radiator to test it just doesn't seem up to the job anymore, does it?

Brad Petersen, Owner, ASE L1 Master Tech, Peterson Automotive, Escondido, CA”

I’m pressurizing the coolant system as I type. It’s been pressurized for over an hour now and I keep going out and pumping it back up to 15psi. It settles at 10psi and holds so just waiting to scope it in a bit

 

Not all radiators are that easy to get to. Ones that use expansion tanks are not as user friendly.
And that process above takes longer.
Sure it will work, but time is money. (In shop terms).

 

It’s got a cold air intake so I had the bank 1 coils and plugs off in a few minutes. Already had bank 2 plugs and coils out for the compression test. I got an extra set of plugs so was just gonna throw them in. But I finally finished the coolant pressure test after letting it sit for a couple hours and scoped it and bam… there’s a little puddle of pink stuff. Blown Head gasket. First test proved itself as I did both. I can see the first test working good for a very small leak that you don’t have to wait for 15psi to push coolant through. Anyways now onto the next step. Replacing the HG’s. You said you wouldn’t do the timing chains and guides right or change the valve shims? Why not? Tnx for the advise man!

 

It depends. The chain is at a minimum coming of the heads.
I guess it comes down to how much the chain has stretched and the color of the internals.
If the internals are tarnished heavily, I'd do the chains, guides and tensioners.
There no better time than now to do it.

As for the valve shims, No.
I wouldn't even remove the cams from the heads.

See the link below for a general idea of how to "gauge" the chain stretch by the tensioner length.
https://www.tacomaworld.com/threads/timing-chain-p0018-p0302-304-306.562849/#post-18457731

 

When I get the new head gaskets do you know if I need to buy the ones for an ‘07 or newer to get the stronger ones?

 

I have an 05 -- had put in a used 08 engine (a different story) but it had a slight HG leak like you're describing. My pressure test would go from 15-10 and sit there as well. I was losing coolant. Once it threw the 040x codes I scoped 4 and 6 and had coolant puddling. So FWIW from what it sounds like mine was a bit worse ... and I did take off 0.007 of the head upon replacement.

I used this for the new HG: https://www.yotashop.com/gasket-set...61/?searchid=4825935&search_query=04112-0P061

2k miles in and it's been rock solid since ... phew! I would recommend the HG route since you never know the condition of the used engine.

 

Had similar situation with kids 08 Tacoma. Had approx 420k on it and the kid told me he seems to have a coolant issue and a slight cold start misfire.

Cylinder 6 was the culprit. Pressure tested, removed number 6 plug and stuck a scope down cylinder and within seconds had a small trail of coolant.

hesitated at first but can’t buy a used truck for 1000 bucks in parts we spent and free labor. Being a Toyota tech for 17 years. I did measure for straighteness and all was good.

truck now having 454k on it now and zero problems afterwards .

replaced 2 head gaskets, main timing chain, coolant cross over pipe under intake (rusted) removed all valves, cleaned and replaced valve seals and all necessary gaskets . All parts from dealer

 

Those are the updated stronger head gaskets in the link right? Did Toyota discontinue making the crap ones hopefully?

 

Great Work! Beyond my means right now. I don’t have the time, tools, or facilities to tackle this job. Gonna have to take it to a mechanic