Head Gasket Screw Up

takza · Post by **takza** » Sat May 21, 2005 4:49 am

Problem might be the thermostat...if it doesn't have the small bleed hole to allow air to pass thru....could have happened that way if an air pocket formed and the coolant didn't get to the thermostat?

I've heard of people drilling a small hole in the thermostat plate.

onium · Post by **onium** » Sun May 22, 2005 10:37 pm

well, I don't think the priming issue was an issue at all after reading your responses and taking the head back off, installing another gasket, putting the head back on, burping the cooling system, firing the engine and having the exact same thing happen as before! There has to be something very obvious that I'm doing wrong here.

My first thought is that it's not the head gasket at all, but the mixture of oil and water suggest it is. I now have the head back off and have checked for warpage on the head and the block and I can't get the thinest feeler between my straight edge and either surface. I just spent a couple of hours double checking that both surfaces are well scraped and free of nicks. That's a check. What else could I be missing here? It seems that the gasket simply isn't sealing with the head or the block. Could there be anything preventing the bolts from torquing up correctly? I've been cleaning them religiously before reinstalling them in the head. I'm guessing that overtorquing by a few lbs would not be a good thing to try? I've been trying to clean both the head and block surfaces meticulously -- does that matter? What's the best way to remove oil? I've looked at the head and there aren't any obvious cracks. Everything lines up...

As much as I like doing mechanical work, three head gaskets in a row is a bit much thank you.

Typrus · Post by **Typrus** » Sun May 22, 2005 11:19 pm

Hmmmmmm......... Is it the same spot all times? Where has it happened? Is there a crack in the block's internal channels? ........................................................ COMPLETELY drain out your oil and coolant, block off your oil and coolant passages as completely as possible, then wash surface with something like Dawn. Dunno if an orange-based cleaner is safe for the block, if it is I'd say to use it. Then THOROUGHLY RINSE IT and dry it with a residue-free cloth or towel.
I personally dunno what else to say.

dug320 · Post by **dug320** » Sun May 22, 2005 11:52 pm

I have read all the posts.

Did you use the correct pattern in torqueing the bolts? If everything is straight there should be no problem.

I wonder if you have a hair-line crack. Your problems just seem to say something other than warped.

takza · Post by **takza** » Mon May 23, 2005 5:42 am

Yep...sounds like a crack. You can't really see the real small ones...might try a magnifying glass.

They use a chemical that will test for cracks...it would likely be in the head...the guys who rebuilt it should do it.

Oil & coolant does make it sound like the gasket.

Wonder if there is a head gasket upgrade for the 3AC...or a gasket compound that would help?

I replaced a head once on an old 230 six that someone had doubled up some gasket material where it leaked...and it actually made a dent in the head surface (cast iron)...had to have it reground...seemed to hold OK. Block was not dented any though..

onium · Post by **onium** » Mon May 23, 2005 11:43 am

I've been really careful with torque and torque-down and torque-off patterns. When it blows, it blows out the front, driver's side of the engine right by the timing cover and manages to mix coolant and oil even though the nearest oil port appears to be one full cylinder width away. When it fails, it's failing big. There was no crack in the block when I removed the head originally, so I can't imagine why there would be one now. So, that leaves a crack in the head as the likely answer. If this proves to be the case I'm goin' to be a bit angry at the reman shop... After doing two, would you recommend sending it in now, or giving the thing one more chance to fire?

Thanks for all of your help.

Rickety Rhino1 · Post by **Rickety Rhino1** » Tue May 24, 2005 7:54 pm

One possibility that hasn't been mentioned is that a head bolt bottomed out, and left the head torqued unevenly. This happened to me (I think): while doing the final torques, I felt the resistance on one of the bolts let up. Since it was near the final torque value, I left it as is. I later asked the machinist how much he had grinded off the head to make it flat, and it was beyond the spec listed in the Toyota service manual! So I concluded that the bolt hit the bottom of the hole in the block and started stripping! Why this didn't happen with all the bolts I don't know. (I'm just a newbie mechanic (have been for 25 yrs) so this is just my interpretation of what happened...) However, I've driven it more than 50k miles since, without problems. I also didn't do any burping or belching of the coolant.

onium · Post by **onium** » Tue May 24, 2005 8:35 pm

oooooh, interesting. I did notice that the head I'm installing has been decked way down -- on glancing at it, it looked like it might have been enough to make this engine an interference - type. I've cleaned out the bolt holes and noticed that some are deeper than others, which might explain how one bolt bottomed in yours while others may not have. I've been thinking that I could have gotten some junk into a bolt hole causing it to torque down without sealing the head, and am planning on blowing some compressed air into all the holes to make sure they are completely clean. However, the decked head issue may be what's really going on here. I'm gonna measure the head and see if it's within spec and won't be surprised if it's not. I might also see if there are slightly shorter bolts on the market anywhere. This thing has one more try before I abandon and take it into a pro, or send this car to tercel heaven

Typrus · Post by **Typrus** » Tue May 24, 2005 10:15 pm

You could grind them down and debur them?

clbolt · Post by **clbolt** » Tue May 24, 2005 11:16 pm

If your head has been surfaced to the point that the bolts are too long, you'll never be able to get the camshaft timing right. If that's the case, I wouldn't trust a replacement head from the same supplier.

How much did this head cost you, anyway?

onium · Post by **onium** » Tue May 24, 2005 11:34 pm

I'm not positive that this is even the problem as I haven't measured it and haven't compared with spec. I hadn't even thought of the valve timing issue, but doesn't that depend on the relative size of the cam sprocket and the crank sprocket rather than the distance between them? but, yeah I've been a little iffy on this head for several reasons, but am not experienced enough to know if I should have been raising a stink:

--came missing one of the exhaust/intake manifold studs. took this off my old head. Didn't seem like too big a deal, but indicates lack of attention to detail.

--was purchased with cam, valves, etc, but was shy two of the bolts that hold the rocker arms on (these are the bolts that the valve cover eventually attaches to) again, failure to double check their parts.

--kinda thought a complete head would have included a cam sprocket. again, took off of old head. not too big a deal

--decking issue(???) if it is one. Could be grasping at straws.

--surface the valve cover gasket mates to wasn't polished. My previous head was. Don't know if this matters.

Price: $225 after core return
Place: Portland, OR's aluminumheads.com -- I live an hour and a half south. (note: if anyone lives in the Corvallis area and wants to fix my car, I'll buy them a beer! ha ha.)

Original problem was simply replacing a busted valve and was going to have the head pressure checked, decked, valve seats ground etc. Figured at the age of the engine -- 200kmi, I may as well buy a completely rebuilt head to ensure most components are back to spec. But, I'm guessing that having this work done on my old head at a machine shop would have been a better way to go??? I'll admit, I'm at a loss here.

clbolt · Post by **clbolt** » Wed May 25, 2005 12:27 am

The problem with the valve timing is one of the relationship between the sprockets. Lowering the head causes the cam gear to have to be rotated in relation to the crank gear because of it's lowered position on the engine. I've known guys who decked blocks to the point that they not only had to buy an adjustable timing gear to correct for this, but also had to rethink the tensioner.

That in itself is not something you'd be likely to run into with a Tercel, but the timing issue could be. If the head has been cut that much, they could also easily have cut too close to a coolant passage.

I wouldn't waste my money on another head gasket. If you have to pull it, make them replace it with another head or demand a refund and your core.

The missing stud was something it should have come with, but the cam gear wasn't. The missing stud and rocker stand bolts would have made me return the head. The non-polished valve cover surface is a bit of a question. Do you mean they didn't surface it after glassbeading the head?

onium · Post by **onium** » Wed May 25, 2005 12:44 am

Ahhh, I think I see with the timing issue.

Yep, they didn't surface the valve cover mating surface after glass beading. Running a finger over it, it feels a bit knobbly while my old head's surface is smooth as butter. The head/block interface is, of course, smooth. I think even I would have caught that one.

The head is off now and with what this forum has told me I agree that returning it is the next step. Luckily, I still have the old core, so don't have to worry about getting that back. I don't think I want another head from these guys after this debacle. I'll just check my old head for warpage and proceed from there if things check out.

BTW: do you know the spec on the minimum thickness of the head on a 3-A? I'm still curious about the bolt issue for future reference if nothing else. Given what I know now, this seems to be the most likely cause of my woes.

takza · Post by **takza** » Wed May 25, 2005 6:03 am

Just put a new t-belt in my wagon and noticed that the timing marks lined up exactly when the belt was under tension....meaning no reworked head.

I'd think your best bet would be to bail on the remanned one and find somebody local with a good rep to do your present head. Or I concur....

dug320 · Post by **dug320** » Sun May 29, 2005 6:02 pm

You should get a medal for your pain and suffering.

I wonder if the machinist knew the toyota specs? My experience led me to get the head done by the company that did the heads for the local Toyota dealerships. Take your original head to their shop. Give them your story.

I would scream as loud as possible when you take the parts back.

Let us know how it turns out.