P0306 head gasket,

T

tcpoob

New member
2005 V6 4WD SR5 160k miles

rough start, shaking vibration for about a minute. drives ok but felt lose of HP. check engine light (CEL aka MIL) is on, along with VSC, TRAC ...

I've a cheapo OBDii reader. showing 2 codes P0306, and P0306 pending. Cylinder 6 misfire. I'd taken it to Toyota dealer service who told me the coil on that cylinder was bad, because they swapped with #5 and "the code followed". I took their words and replaced all spark plugs, and just the ignition coil on #6. Also put in new car battery. I was happy all the lights were gone for a day or two. But today they all came back and stayed on. Scanned it, same code as before all that work P0306.

How do I root cause this - especially based on the description on the board, this sounds more like the leaking head gasket issue that plagued. I don't mind paying a mechanic to get to the bottom of this but what should I ask them to do so they don't just scan a code and tell me to replace the plugs / coils ? Should I ask for a leak-down? What would definitely confirm it's a HG issue? Car never overheated, coolant level seems normal, slightly above low. If there is lose of coolant it's not noticeable to me. I tried to smell the coolant but I am not sure what to smell for, the whole area smell gas anyway ...

Thank you very much. FYI, I'd previously started another thread on this but at that time I naively thought it was the loose fuel cap. I don't believe that's it now especially the codes thrown are always almost P0306.

I think I hear some gurgling water sound when I start the engine which I never noticed before - but then I never had to look for trouble signs when it just ran...

I do have the spark plugs I just took off and can post a picture if it might show anything.
 
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I had a feeling from your last thread. I'm sorry to hear it. Leak down test is an easy way to tell.
 
Do a compression test, you can rent a gauge from an auto store.

Post the numbers here.

Also look inside the CYL since you pulled the plugs. Do you see any CYL without carbon (looking clean) while other CYL have lots of carbon? That would be sign of burning some coolant.

Note to self: why am I lost in the 4th gen section?
 
what else to replace while doing a HG job

left the 2005 v6 1gr-fe 160k miles at Toyota Dealership overnight
they called to report seeing coolant in cylinder #6

1.
can you really "see" coolant from the spark plug hole, with naked eyes? Or is it typical that inspection camera etc imaging gadgets are used to go deeper down the engine to find this? they didn't do a compression/leakdown.

2.
and, given the mileage, sounds like the HG on the other bank should also be replaced, i mean, would be very sorry for the other side to fail after a major job like this most of the cost is labor. what else would make sense to replace,
* the timing chain,
* water pump
* ...

3.
what are the chance for the heads or other parts on the way to need re-surface machine job? if so, that would cost me extra, i assume. i think i might have caught this early.

4.
i am thinking about trade-in. at this mileage, the truck is probably only worth what, $8k ? it's babied since day 1 and in outstanding condition. but i'd hate throwing that amount of money $2k to $3k and not knowing what else might break next ... please advise, thx. would hate to say farewell to this group
 
tcpoob said:
left the 2005 v6 1gr-fe 160k miles at Toyota Dealership overnight
they called to report seeing coolant in cylinder #6

1.
can you really "see" coolant from the spark plug hole, with naked eyes? Or is it typical that inspection camera etc imaging gadgets are used to go deeper down the engine to find this? they didn't do a compression/leakdown.

2.
and, given the mileage, sounds like the HG on the other bank should also be replaced, i mean, would be very sorry for the other side to fail after a major job like this most of the cost is labor. what else would make sense to replace,
* the timing chain,
* water pump
* ...

3.
what are the chance for the heads or other parts on the way to need re-surface machine job? if so, that would cost me extra, i assume. i think i might have caught this early.

4.
i am thinking about trade-in. at this mileage, the truck is probably only worth what, $8k ? it's babied since day 1 and in outstanding condition. but i'd hate throwing that amount of money $2k to $3k and not knowing what else might break next ... please advise, thx. would hate to say farewell to this group
Click to expand...

I would fix it and probably will if this ever happens down the road.
 
why only #6 cylinder head gasket leak

it sounds most get the head gasket leak in the #6 cylinder. Is that a design flaw on the head gasket - i mean, why does it always leak into the #6 cylinder, not the other ones?

thanks
 
tcpoob said:
it sounds most get the head gasket leak in the #6 cylinder. Is that a design flaw on the head gasket - i mean, why does it always leak into the #6 cylinder, not the other ones?

thanks
Click to expand...

As a diehard 4runner\Toyota fan, it is very painful for me to say it… but in IMO: it is a design flaw….
Heating\cooling cycles makes this area (#6cyclinder) moves more (or unequally) than it should…
 
design flaw

It is a definite design flaw as photos of failures are identical, and the gasket has been redesigned by Toyota.

Easiest way to check if p0306 is the head gasket (which most times it will be), is to smell your coolant. If it smells like gas instead of just antifreeze, it is toast.

The rough start is due to a small amount of coolant leak when the engine is cold. The leak seals when the engine heats up

Time to shell out the $3000 or so for the fix. 28000 miles on my fix, running fantastic.

The fix is worth it in my opinion as with over 200k miles I have had no other major failures in this vehicle. Brakes (pads/rotors/calipers), exhaust, alternator, wheel bearings and CV axles are all I have replaced. Wear and tear happens, I can live with these simple repairs. Best vehicle I have ever owned.
 
tcpoob said:
2005 V6 4WD SR5 160k miles

rough start, shaking vibration for about a minute. drives ok but felt lose of HP. check engine light (CEL aka MIL) is on, along with VSC, TRAC ...

I've a cheapo OBDii reader. showing 2 codes P0306, and P0306 pending. Cylinder 6 misfire. I'd taken it to Toyota dealer service who told me the coil on that cylinder was bad, because they swapped with #5 and "the code followed". I took their words and replaced all spark plugs, and just the ignition coil on #6. Also put in new car battery. I was happy all the lights were gone for a day or two. But today they all came back and stayed on. Scanned it, same code as before all that work P0306.

How do I root cause this - especially based on the description on the board, this sounds more like the leaking head gasket issue that plagued. I don't mind paying a mechanic to get to the bottom of this but what should I ask them to do so they don't just scan a code and tell me to replace the plugs / coils ? Should I ask for a leak-down? What would definitely confirm it's a HG issue? Car never overheated, coolant level seems normal, slightly above low. If there is lose of coolant it's not noticeable to me. I tried to smell the coolant but I am not sure what to smell for, the whole area smell gas anyway ...

Thank you very much. FYI, I'd previously started another thread on this but at that time I naively thought it was the loose fuel cap. I don't believe that's it now especially the codes thrown are always almost P0306.

I think I hear some gurgling water sound when I start the engine which I never noticed before - but then I never had to look for trouble signs when it just ran...

I do have the spark plugs I just took off and can post a picture if it might show anything.
Click to expand...
did you replace the HG?
 
tcpoob said:
it sounds most get the head gasket leak in the #6 cylinder. Is that a design flaw on the head gasket - i mean, why does it always leak into the #6 cylinder, not the other ones?

thanks
Click to expand...
I had the same problem 2004 4R with 147 thousand miles. My husband replaced thr HG now more problems please help
 
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