Coolant Reservoir Bubbling and Filling Up.

Leak on #5, unless pics are misleading, like trick of light, #5 is pretty much clean of carbon build up, #6 has carbon build up (not as much as expected)

Clean cylinder means coolant has been leaking into the cylinder and basically 'steam cleaning' it.

OP, do you have more pics? To be sure?

Also are you sure you have cylinder numbers correct?

5 is on passenger side, 6 is on drivers side.

 

Scope the other cylinders and compare.

 

Can you get a better pic of what looks like a 'chip' in the first pic? Almost looks like the piston hit a valve?

 

Was on a time crunch yesterday. Probably won't be able to test the others today. I learned for best picture, rotate Pistons to bottom of stroke.
Note the yellow residue on both plugs?
It's #5

 

I am facing a similar issue.... after about 60 miles, all of the coolant is in the overflow and bubbling. Temp rises when at a low idle or stopped. I have personally done a block test and a pressure test. Both passed (see photos below). Since the combustion leak test failed, what are the chances that it is a water pump issue? Since it doesn't want to suck any of the coolant from the overflow, it is acting like a pressure issue.

Additional information:
- My heat works when it is overheating
- I do not know when the fluid was flushed, water pump, or thermastat was changed

Combustion Leak Test Results


Pressure Test Results

START


AFTER 2 MIN


AFTER 5 MIN

 

Go back to Page 1 - Post #7 of this thread.

 

Yeah i have looked for bubble at the top of the radiator neck and it was not bubbling alot. Since the combustion leak test was inconclusive, i wanted to reach out. I plan to remove and check spark plugs next. Any negative to just change them while i have them out?

 

What are the chances of a water pump going bad?

 

Same as any other component. In my experience, they start out leaking from the weep hole and then get noisy.

 

I'm currently rebuilding my head gasket now on my 2006 4.0L
https://www.tacomaworld.com/threads/2006-4-0-v6-head-gasket-overheating-rebuild.609265/
I had the same issues.
The coolant reservoir would bubble up and over flow and that was my coolant loss.
At first it was not bad then it got 10x worse.
I had no water in my oil.
No check engine lights.
No white smoke.
No leak in my radiator.
Just a gasket leak where exhaust was entering my cooling system and boiling nt coolant.
It cost me around $900 in parts and maybe 2 weeks in labor just bc I worked graveyard and needed to find time.

 

I bought a new tstat and spark plugs. My plan is to remove spark plugs and see if coolant is in the cylinder. If i cant see any coolant then I will take to shop for compression test. If i do see coolant then I will take to shop for head gasket. In the process i plan to change plugs just because i dont know when they were last changed and tstat because it is so easy.

 

Dropped a bit of the oil to look for coolant causing milk shake and oil was clean. Fan clutch doesn't wobble so bearings are good and it has resistance when hand spinning so it is good.

 

UPDATE: Had the head gasket replaced and all is back to normal.

I did my diligence and replaced what i could to see if anything would change. However, the coolant issue was still occurring so i had the head gasket replaced. While they were in there, i had them change the chain guide, water pump, head bolts, and some other nuts and bolts. Before taking it in, I replaced fan clutch, serpentine belt, tstat, and lower radiator hose.

So i shouldnt have any issues upfront for awhile... hopefully!

 

What was the cost? Just curious.

 

Original estimate $2700 plus tax. However when i went to pick it up, it increased to $3200 plus tax. They put some new parts on the inside or atleast i hope they did.. no way to really tell. Also, i was quoted at 19hrs (Head Gasket Replacement) but they billed me for 24 (Head Cylinder Assembly Replacement). I pressed them about the difference and why but no one in the place could tell me. The service adviser said he would call toyota to determine the difference but overall, that is the time they spent on it. That irritated me and I will continue to press them on it because i feel a bit bait and switched. Like they quoted me a good deal then once they got the truck in the shop, did what they could to get the price back up to original price.

Overall, the price was still around the same as other shops and I dont mind paying for new parts while they were in there. My mindset was "change any wearable item inside because i dont want to go back inside the engine". However, I wish they called me before replacing parts so i knew what i would be walking into when i went to pay and pick it up instead of being blindsided by a $500 increase. Not the best communication or tactfulness.

 

Yea I feel it bro.
They told me originally it was going to be over 20 hours and toyota in Tracy Ca didnt wanan do the head gasket job instead they wanted to charge me 12k for new engine.
I did the whole thing myself for under 1k.

 

Right on! I just didnt have the time or space (ie i live in an apartment complex and do all of my fixes in the parking lot ha). Granted they did give me a 2019 highlander loaner for free.

 

Not for free. It cost you $500.

 

Nope... no line item for it on the invoice or are you referring to the price increase? Because technically $350 of that was other new parts.

 

I was referring to the price increase. Tongue in cheek.