yojimbo

Hi. I just got done pulling the head out of my 89 4runner (22RE, 198k miles). A leak-down test said it had a blown HG on cylinder #3, which was allowing exhaust into the coolant system. So being semi-handy and about $1800 short of the estimate they gave me to fix it, I decided to do it myself. There were a couple hiccups, but thanks in large part to all the advice on this forum, I got the head off without too much stress, and I'm pretty happy about that.

So I pulled the head off and took a look at #3, and this is what I saw:



There is an eroded area along the top of that hot-dog shaped hole, and it extends at one point into the circle of the cylinder itself, which I'm guessing was the source of the exhaust/coolant leak. Having never really looked at a cylinder head before, I'm not sure if what I'm seeing is normal wear or not. There is similar erosion on a couple of the other holes/ports in the head, but nothing as extensive this one. So my question is: what's my next move? I'm reasonably sure that if I were to slap another HG on there and put things back together, it would fail right away.

So, is this repairable? Can this be machined out (it's hard to see on the photo but it's probably a mm or two deep), or welded, or is there a goop of some sort I can apply to fill that area? Or is my next step a new head?

Any advice pointing me towards my next step is much appreciated, thank you!

TOYOTA 1

your correct, if you just throw another HG on there then it will just blow in no time.

your only option is to take it to a machine shop. or buy a new head, witch you might have to anyway. but that one looks fixable.

abecedarian

you're likely looking at the result of electrolysis, which is caused typically by using 'impure' water to mix with the coolant (like tap or bottled drinking water). A breech of that size, which looks really small, will cause a significant amount of coolant to enter the cylinder during the later part of the exhaust stroke, and all through the intake stroke of the engine when cooling system pressure is higher than the pressure in the cylinder.

As for the next step... obviously the head need repaired or replaced, so as mentioned, a qualified machine shop should look at it and determine if it is able to be resurfaced / re-used.

And, my side thought of the moment:
...if you think you may be wanting a bit more power from the engine, this would be the perfect time to consider a cam since changing cams often requires replacing the head gasket. NOW I AM NOT SAYING GET A PERFORMANCE CAM, just that if you want some more power (and trust me, you won't get a lot), and think you WILL want one in the near future, there's no better time than the present, while the engine is apart.
(you did say you did a leak-down test, so presumably you did a compression test too, so by that you'll know if the rings need re-done.)

yojimbo

Thanks guys for the responses. I took the head into a machine shop today, and they gave me an estimate of $265... $45 for welding to fill the corroded spots, $45 to resurface the head, and $175 for a valve job, which he said would be necessary due to the temp used for the welding.

Does that sound about right? What risk am I taking if I just have the corrosion fixed and the head resurfaced, but I skip the valve job? Is it likely to have needed a valve job at 200k miles anyway? And if that's a reasonable charge for this job, should I spend that much on this head, or just look into buying a new one? The machine shop fella said a new one would be in the $350 range, I'm assuming that's ready to bolt on but I'm not sure.

Sorry if these are basic questions but this is my first time dealing with some of this stuff and I'm out of my comfort zone. As always your advice is much appreciated, thank you!

DupermanDave

You can almost get a re-manufactured head for $265. Remanufactured heads come with new valves/guide/seals.

Shop around. Ebay has good priced ( i dont usually like ebay, but for car parts im seeing very good prices) www.22re.com has good prices on heads, and especially engnbldr.com