blown head gasket.... possibly?

H

hvguy

New member
When I start up my 4runner "V6 5vz-fe" after sitting for a few hours or over night, it stutters like its only running on 5 cylinders.

I have herd that toyota made bad gaskets during a certain time. My engine was replaced with another a few years back and I think I got the year that has the bad gaskets.

also- after driving for a few days, I have to top off my coolant because the engine starts to overheat- and I just replaced the thermostat, coolant, hoses and radiator. So I know its not the coolant system.

What I'm thinking is the HG has a small leak between the coolant port and the cylinder and its slowly leaking into the cylinder while its sitting and slowly burning coolant over time.

BUT its not smoking =(



anybody think its all related to a leaky HG?
 
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Four years ago the exact same symptoms appeared in my '97, stuttering and having absolutely no power. I was going through coolant at a ridiculous rate as well.

Needless to say, I replaced the head gasket and once I got it jumped started afterwards it has run great ever since.

As far as the replacement itself goes, if you would think about doing it yourself, be prepared for it to take you some time unless you have done it before. I took pictures of every step I did in case I missed something in the re-assembly.
 
I took my old engine apart and I just did a port match job on the head and intake on my corolla so its not going to be a problem.



does anybody know where to get a TRD thin head gasket?
 
no prob,

btw, the torque specs for the 5vz head gasket are

1st - 25ft/lbs
2nd - 90degrees
3rd - 90 degrees
4th - 13ftlbs

the 4th pass doesnt make sense to me, but I got those out of the dealer handbook for the 5vz engine.

and you do not have to replace the head bolts after you remove them, or on any toyota's.
 
jranger35 said:
Kabal, any chance you can post those photos here so we can see the steps? I've only replaced a HG on a civic.
Click to expand...

I have been searching for them all day, I think they got lost on one of my fried hard drives.. :(
 
If you remove the heads, have them pressure tested. I have repaired several that had coolant leaking into the cyl's from a crack in the head. The cracks are usually between the valves. If they pressure test ok, have them surfaced and since you have them off, have them grind the valves if its a higher mileage truck
 
In many cases of a blown head gasket, the coolant will leak into the engine oil. Check the oil. If it is creamy or foamy you may have a blown head gasket. Many times you can just look under the oil cap. If there is minimal foam it is sometimes just condensation. If there is alot, it could point to the HG. If you find foamy oil on the bottom of the oil cap, clean it off and inspect it daily to see how long it takes to load up again. There are a number of other tests to do to see if it is really a blown HG.

Tom
 
toytech76 said:
If you remove the heads, have them pressure tested. I have repaired several that had coolant leaking into the cyl's from a crack in the head. The cracks are usually between the valves. If they pressure test ok, have them surfaced and since you have them off, have them grind the valves if its a higher mileage truck
Click to expand...

Can I do a compression test to determine it myself?

and I checked the oil and its not milkshake, and its got 3k on it.

And what does grinding the valves do?
 
hvguy said:
Can I do a compression test to determine it myself?

and I checked the oil and its not milkshake, and its got 3k on it.

And what does grinding the valves do?
Click to expand...

A compression test wont tell you for sure if you have a cracked head. Usually the cracks are small right between the valves and wont lose much if any compression. If you had access to a boroscope to look into the cylinders while the cooling system was under pressure that would tell you.
You wont for sure have water in your oil. They can leak into the cylinders without getting mixed with oil.
Grinding the valves is basically like making the valve faces and seat 'new'. Its a wise choice since you would already have the cylinder head off
 
Hmm, So I took the intake all apart, even the manifold under the injectors, and OMG! it is sooooo gunky.

I cleaned out the intake where the injectors mounted up to and I didnt find any crack.

And I dont think the head has coolant ports in it... I could be wrong, but I looked down in cylinder #3 and didnt see anything different than any other. "btw- It threw a P0303 which is a cylinder number 3 misfire. And its still loosing coolant.

I did a quick compression test and all cylinders read within 10psi of 190~200.


any ideas? ive got to have the truck back together before friday =(
 
You wont see a crack between the valves unless you remove the cyl head. The crack would be in the combustion chamber. Yes...the head does have coolant passages. They need them to stay cool
 
toytech76 said:
You wont see a crack between the valves unless you remove the cyl head. The crack would be in the combustion chamber. Yes...the head does have coolant passages. They need them to stay cool
Click to expand...

awesome, I wasnt for sure, the only head that I have taken off is on my 4AC corolla.
and yes, your right, I just went back and looked at the pic and its got passages.

sorry for the mixup, ill take the head off now and take a look see.

be back in an hour or so.

heres a quick update pic.


161ye5j.jpg
 
thank god, it was only a blown head gasket.
"wipes sweat from forehead"

And it was nearly impossible to remove the head bolts... Me and a buddy had to switch off every bolt because of fatigue.

pics are as follows: leaky head gasket between the cylinder and the coolant port on cylinder number 3.

2hydvr9.jpg
 
after getting the other head off, and power washing it, along with the valve covers and intake, I began the long process of taking the old HG residue off.

Got the first head knocked out in about 20 minutes :D , then I started on the left bank and noticed some weird notches in the combustion area of the head, along with some weird buildup on the intake valves. The marks looked like as if it had burned off the tip of a spark plug and fell into the cylinder and got smashed around. But I looked at the piston and I didn't see anything/.

any ideas?

mbh75e.jpg

66ks20.jpg

2us7cpw.jpg
 
hvguy said:
cleaned it up a bit and its not sooo bad, but its still scarred

vzfwhy.jpg
Click to expand...
That left hand intake valve looks pretty beat up. I would check the seat area for that valve at least. As far as the chamber rash is concerned if you get it magnafluxed and there are no cracks I think you could polish most of that out and it would run OK. You might get carbon hot spots. Something nasty happened there for sure.
 
thanks, im probably going to take the wirewheel that i use to take all the HG residue off and see if i can polish it out a little
 
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