Popped a head gasket.

Bought a '96 3.4 with 140k a couple of months back and haven't driven it too much.

Yesterday it started drinking coolant - drank enough that the temp gauge started climbing like mad, and I pulled over (before the temp gauge got to the red, but barely). Cooled it off and limped it a couple of miles to a friend's shop.

Did the test - cooling system tested positive for combustion gases. Filled it with coolant (about a gallon) and drove home. The lid popped off the coolant reservoir on the way home, and I was down another 3/4 gallon.

So now I'm looking at doing the head gaskets on this thing, and I'm wondering a couple of things.

First, what all parts do I need? I assume I need head gaskets, intake mani gaskets, exhaust mani gaskets, probably a throttle body gasket - what else am I not thinking of? Timing belt has recently been changed, so I'm not gonna do a new one of those.

Second, does anybody have any advice specific to doing this job on a 3.4? Things to look out for?

 

a head gasket set contains all the necessary gaskets to rebuild all the heads a vehicle has. rock auto recommends buying some head bolts as well.

just keep in mind it is a lot of work to tear down a 3.4 liter to get to a head.

tear down intake, exhaust, ignition, fuel injection, power steering pump, AC compressor, 3 belts, fan clutch and fan (don't forget to protect the radiator, you have to pull the crank pulley off and it's easy to smack the radiator when doing this), 2 front timing covers, timing belt, cam shaft pulleys, valve covers, then remember how to put it all back together.

you may also want to get the head pressure and vacuum tested to make sure the valves are still good. and also maybe resurface the head or just have it rebuilt.

get a service manual. good luck!

 

Yeah, I've pulled heads before, just not on this motor. I'm pretty comfortable that I can do the job, just wondering if folks had any specific tips.

 

Guess the only tips i have is that you have to remove the PS pump cause it's bracket is connected to the fan pulley mounting bracket. and you may not have to do the AC compressor cause I think that's just in the way of getting to a bolt for the hydraulic tensioner.

 

I recommend removing the radiator, of course you can do with out it but you get more space and not a hole in your radiator. one other thing is check to see if the coolant cross over is seeping, if it is you will know use fipg to reseal it.

 

I'm replacing the compressor anyway because I sheared the head off a bolt trying to swap a leaky AC line. I have the part from my parts truck, so no big deal. System is already empty from the leak, too.

Thanks for heads-up on the PS pump.

 

Thanks - I'll definitely be careful of the radiator. Truck is actually a T100, so there will be a little more room than on a Taco. I just post in here because it's the same motor as a Taco, and nobody really hangs on the T100 board (and my other truck is a '96 Taco, so this is where I've always been).

If I bungle the radiator, I actually have a spare working one from my parts truck.

I'll check the crossover, and good to know it doesn't need a gasket.

 

A head may be warped or it could have a lot of corrosion. Head gaskets don't just blow for no reason, or so they say. Overheating with low coolant exposes the heads to higher temps compared to simply overheating because of a clogged radiator while maintaining full coolant for example. Just be prepared in case there's a problem with a head.

 

Second what he said. I would just add that you find a reputable machine shop, take the heads in to be straightened and surfaced. While youre in there, it would be worth paying extra and having a valve job done with new ferules and guides. Have the valves ground if necessary and refitted (should not need to).

The farther you can tear it down, the cheaper it will be for the outsourced work. Ive had experience with snapping camshafts of BMW inline 6's, luckily its very difficult to do this on a 3 cylinder camshaft.

I would just remove the radiator to avoid damaging it. Place a thick square of cardboard in the area the radiator would go to guard the A/C condenser from damage.

Im curious to what your approach will be to the rear crossover exhaust pipe. From what ive read some people do, they will have a second person assist them, and lift up both heads with the crossover connected, rather then trying to unbolt it while in the engine bay. I haven't done this before on the 3.4L, so i cant say which way is better.


And ONLY ONLY ONLY use OEM parts!! No Chinese ebay shit.

^ Most important part.

 

Get new head bolts. They are one-use-only torque to yield (?) bolts.
For the head gasket itself, use OEM if you want it to last.

 

New head bolts: yes, sounds like the best plan.
OEM parts: yes, which is why I am making a list rather than buying an aftermarket kit.
Rear crossover pipe: I'm gonna pull it off and put new gaskets in anyway. It doesn't look that bad to get to on the T100. There's lots more room under the hood than on a Taco.

Remembering how to put it back together: yeah, that's the best way to do it. No bolts left over!

 

So I finally got deep into this on Friday. Someone had obviously been in there before, a long time ago - I suspect a Toyota tech did the original recall replacement of the head gaskets under the warranty. Whoever it was did a pretty sloppy job.

On the passenger side, the exhaust bearing caps were on the intake camshaft and the intake ones on the exhaust.

Two of the head bolts were so loose that they turned with no resistance - not even finger tight. I think this explains the exhaust gases in the cooling system. Still not sure where all of my coolant was going - maybe I will learn more when I pull the other head.

I'm going to pull the driver side head tomorrow and take them both to a machine shop. Wish me luck that the heads and valves are all still ok.

 

You will notice a nice change after that machining she should be a little quieter as well. just did one on a cummins 5.9 and the noise difference after was incredible! Good luck!

 

there were a couple of exhaust manifold studs loose as well, and bad gaskets at almost every exhaust junction. The truck has been so loud it was unbelievable. I think just sewing up all of the exhaust leaks is going to make a big difference.

 

If you get a high $ quote for machine work, price out complete heads from http://www.cylinder-heads.com/

 

Let me tell you a little trick. Put the bolts back where they were after you take the part off or put them in the removed parts bolt holes and you will lessen the chance of having left over bolts. I have seen too many people just randomly throw bolt, screws, nuts in to a bucket. Doing that will make a 4hr job into a 8hr job.

 

Sounds good, dude. let us know the end result

 

Thats a good habit to have. I usually use a buck of small ziploc bags. Ever section i work on ill put i a separate bag, then simply mark it 1, 2, 3, etc as i progress, then count backward when reassembling. It works well when taking apart interior and body panels.

 

Another disassembly/reassembly 'trick' that we didn't have easily way back when is pictures.

Take the time to actually use a cell phone camera for something useful. Like what it looks like as you take it apart.

 

Yeah guys, I take pics before I take something apart, then put the bolts in labeled ziplock bags. So hopefully it will all go back together smoothly.