Possible Blown Head Gasket

I've been fighting with coolant loss for a couple weeks now, some of you may have seen my post about it. After flushing (with distilled water), replacing the thermostat, and refilling. I'm still losing coolant. Was thinking the system must have been just purging air bubbles through the sometimes overflowing reservoir somehow. I've added coolant (a couple different times) when I've noticed the reservoir low.

Not being satisfied with the possible causes in my head, ive still been doing a LOT of searching and reading up on this. Then I came across a post here on TW about a BHG, and a tell tell sign of it is the sound of water sloshing or pouring from the dash / engine area. I've heard this sound multiple times. So I've got questions.

I'm going to schedule a shop visit to do a "sniffer test" on the coolant system. I've seen on these forums that the 4.0 often passes this test even with a BHG, so I still want to use a scope to look at the cylinders myself.

Recommended scope that won't break the bank for a rookie wanna be mechanic like myself?

I know to look for a "squeaky clean" piston but I understand it's normally a certain cylinder (#6 I think) to look at where the problem normally occurs. What's the cylinder # pattern?

If I find I DO have a BHG, is it worth it to fix? I've got like 269K on the clock, would love to keep this truck.

There's a small chance that I may do the work myself, should I replace just about everything (water pump, alternator, all hoses ect.) while I have it all off? Everything under the hood is bone stock from the factory. I have never had to replace anything in the 12 years I've owned this truck.

If I pay a shop to do the work, what does that normally cover? Do they replace wear and tear items as they put it back together?

Ok I think that's it, haha... yall let me know anything I need to know.



Edit to add... truck has never run hot... so the heads SHOULD still be ok and not warped

 

Do you have a misfire on startup (especially the first start of the day)?

You should be able to pick up a decent borescope for under $100 just be sure to check the reviews first.

I've found a good method to confirm small HG leaks that won't show up on a combustion gas test is to pull all the plugs (or the one(s) on the misfiring cylinder(s) if you have a misfire), pressurize the cooling system to the relief pressure on the cap, let it sit for several hours or more, and look in each cylinder with a borescope for a puddle of coolant.

 

Remove the spark plugs and take a look at them, a spark plug burning coolant would be like powder white.

Those 4.0 head gaskets are not easy, only tackle that job of you are confident. I've done one, you pretty much have to strip that motor down to the short block.

About 4 years ago toyota quoted my brother about $2.5-3k for that job

 

Rear piston on drivers side is usually the culprit if memory serves correctly

 

Here's

DEPSTECH 5" IPS Display Endoscope, Dual Lens Inspection Camera with Light, 7.9 mm HD Borescope, Sewer Camera with LED Flashlight, 32 GB, 5000 mAh Battery, Carrying Case, Detachable Snake Camera-16.5ft

one that you can get for around $110. I have used it. Not sure what your budget is. This one has a side camera view option. That not a must have but it does allow you to look at the cylinder walls in addition to the top of the pistons. My leaks were small so I was not getting puddling on the top of the pistons. This

DEPSTECH Wireless Endoscope, IP67 Waterproof WiFi Borescope Inspection 2.0 Megapixels HD Snake Camera for Android and iOS Smartphone, iPhone, iPad, Samsung -Black(11.5FT)

one didn't work for me but it is cheap and has decent reviews. It uses your phone's display but it kept freezing up with my iPhone so I returned it. Maybe the one I got was defective.

The head gasket on my engine was leaking on cylinders 4 and 6. My truck ran great with no noticeable issues other than mysterious coolant loss. I tried a block tester and it did not work for me. Rent a cooling system tester from your local auto parts store like Autozone or O'Reillys.

Whether it is worth or not is up to you. It depends how much you are willing to spend or risk. If you like your truck then I would suggest repairing it. You know the condition of it and how well it was cared for. More than likely your heads will be in good shape with a worse case scenario of needing to resurface them if at all.

In October of 2022 in the Chicagoland area I got quotes of around $5000 to repair the head gaskets. This is only to replace the head gaskets and reseal the engine. That did not include any machine work, water pump, spark plugs or thermostat. I would suggest doing those since you are in there especially if they haven't been done yet or for sometime. I didn't replace my timing components but others here in the know suggest doing so. If you do, stick with OEM. I don't think it makes any sense to replace working factory timing components with aftermarket ones.

You can take a look at my repair here as it has information on diagnosis, tools, parts, etc. My truck had 295k miles on it when replaced them. It has around 314k now.

https://www.tacomaworld.com/threads/4-0l-v6-with-bad-head-gasket-repair-or-replace.781269/

 

I have that first Depstech camera, the 5" / $130 one with a separate side-view camera built into the head. Highly recommend. Used it to scope my cylinders, here's what the video quality looks like. BTW for reference the engine had no problems at all. No codes, no oil or coolant burning/loss, normal power, mpg, etc. Just a baseline for future reference at 150K, 200K miles, etc.:

https://www.youtube.com/watch?v=P2Lp01qZ3MQ

https://www.youtube.com/watch?v=3S_iXxLhG8Y

 

Toyota in 2019 quoted me $2400 for both head gaskets with parts and labor
I cheaper out and haven’t had an issue, thought it was out and ended up being a plug

 

If someone can get this done from a reputable place like Toyota for $2400 then do it. That’s a steal all day long in my opinion. This is not a hard job but it ain’t easy and it’s definitely time consuming for a DIYer.

 

So I just had the sniffer test done and it indicated a blown head gasket. FML...
So am I correct to assume that since my truck HAS NOT yet run hot that my heads should NOT be warped and SHOULD be ok to replace the gasket with out any other major repairs needed right?

 

Not sure what the sniffer test is, but I making the assumption your head gasket is bad based on your confirmation. I think there is a low chance that your heads are warped beyond repair since your car is running fine currently. In my opinion, worst case scenario is that you need to have them resurfaced. Obviously nobody can guarantee it until disassembly so there is always a risk albeit that it is low.

Since you have higher miles, you will need to check and inspect your timing components. There are a lot of people with more experience than I, that recommend replacing your timing components while you are in there. E.g., timing chains, guides and tensioners.

You should also consider replacing the water pump if it hasn't been done yet.

 

Forgot to add. The valve grind kit, which includes the head gaskets, also contains new valve guide seals. You will want to replace those. Also, when you have the heads checked, they should also check to see if your valves are leaking. Most folks will clean up the valves and then lap them to reduce or eliminate the leaks.

 

As big as the job is, you should get it resurfaced and pressure checked while the heads are off.

 

If the head is true and within spec, I wouldnt get it milled.

Some people report issues with machining then timing out after.

Typically with coolant consumption we don't machine. But we check with a straight edge.

 

Does anyone know if Toyota sells a timing chain kit that comes with everything? Seems trying to track down every single individual part will be a PITA.

I see timing chain kits for sell when I search Google, but would much rather have all OEM Toyota parts in there.

 

Also need to add....

I was about to say F-it and trade the bish in on a new one, but I decided against it. One shop quoted me 3600 for the tear down and rebuild but I would have to pick up the heads and take them somewhere to get worked. That was almost ok with me until I realized that this price doesn't include new water pump, timing components, new hoses ect. My way of thinking is that if the engine is going to come a part, may as well replace the wear and tear parts while it's broke down. I dont want to break it down again. So I've finally decided to do the work myself. I'm confident that I can get it all broke down, I only question myself with "top dead center" and timing type crap when putting it back together, but ive got a buddy that knows about all that and said he would come help onnthe technical stuff. So yall wish me luck, im sourcing parts now, and looking for a machine shop quote.

 

They sell an engine overhaul gasket kit - 04111-0P071 full kit - 04112-0P061 is a smaller set.

Timing chain 13506-AD010
Tensioner 13540-AD0101
Side piece 13507-AD010

Water pump - Aisin on Rockauto

these are the notes I have for my 06 TRD Off Road. Please double check these numbers are correct for yours.

Good luck.

 

No timing kit available from when I did this job.

This is a list of part numbers for a 4Runner, same engine, that you can use to get started. Maybe you can cross check them. Order your parts online as it will take sometime.

Btw, I think you made the right choice to do it yourself. We will be here for support. .

Also, if you are able to take the engine apart and start putting it back together, you will be able to figure the timing part out. It will all make sense once you get the timing components disassembled.

 

just buy the master rebuild kit, comes with everything

 

It does not come with timing chain parts.

It was all of the gaskets.

 

Anybody know where I can get a FSM? I haven't started on this job yet, still looking at all the parts and the astronomical price this is going to be. Kind of sucks that I just spent like 3K on this truck with new wheels, tires, TPMS, and new headlights too. So my bank is busted at the moment. But my wife and I have 3 cars, so I can take my time, order a few hundred dollars worth of parts here and there. Definitely want that FSM to reference while doing this for torque specs and patterns plus all the other stuff that I dont even know to ask about right now too. Lol