Resurface head and replace valve seals etc at time of headgasket replacement or not?

Check against flatness spec's with a machinist's straight edge? Just for giggles you check it first with the "straightest edge you've got on hand", trying several. You basically press the straight edge against the face, and try slipping a feeler gauge under at various points.

Never mind, see you've got straight edge and feeler gauges.

The flatness specs are in the bottom link in my signature. (on a phone turn it landscape to see signatures)

 

If it was my car...yes...get it done right. It's a GEN III with 150K miles...and the head gasket blew.

 

Just take a paint and body sanding block with 220 grit Wet-o-dry with WD-40 and go over the gasket surface. Do not use a roll-loc disc, it will gouge in and cause low spots. Then check with the straight edge. Machining is not necessary if it's within flatness specs. But machine shops will always do it anyway. While you have it apart it doesn't hurt to do the valve seals although I would use OEM seals. Fel-pro won't last as long.

 

Use a razor blade to clean off the head. Maybe a brass brush to clean it up. Then check the head.
You shouldn't do any sanding. If it's not warped, no need for the machine shop.

The block is cast iron and it's not going to warp, if it did, you would've known it because the engine wouldn't have worked

Valve guide seals are easy. You just need the spring compressor and a strong magnet to grab the retaining clips.
If the valves are leaking, use valve grinding compound with an electric drill and popping the valve, to seat them in.

You can do that in an afternoon.

 

NEVER sand an aluminum head!!!! Use a green plastic brillo pad and elbow grease.

You can usually borrow a valve compression tool at your local parts store. They will charge your credit card and refund it when you return it. Make sure it's in good working order BEFORE you leave. I've run into a lot of broken/nonfunctional tools. They are usually pretty good about that, but you don't want to get blamed for breaking something that you didn't break.

I personally wouldn't use a drill with grinding compound on the valves. If they're leaking and it isn't carbon deposits - it needs to be measured and machined; but at 150K - it's probably OK.

Good Luck...

 

I do not know where you got your Gen 3 engine from, but the Toyota OEM engine has an aluminum block.

 

You could have rented one from autozone for free. But $20 is a good price.
the lifters have nothing to do with the valve and seat. "Lapping" in the valves
removes a little material from both surfaces so there is an exact fit and the combustion
gasses do not leak and you lose no power.

If they are not leaking, you don't have to do it. Just replace the guide seals.

 

The car was wrecked and the head gasket failure never threw codes? Did you ever get the severe metal to metal rattling and shaking caused by coolant induced misfires?

Did you look in the cylinders with a borescope?

It would a bad day in Kansas City if a hg repair did not solve the problem and it was a cracked exhaust heat recirc system.

 

Gen3 does have an exhaust heat recirc system - they just don't leak as much as the early gen4 systems. However some do leak and will cause billows of steam.

 

The exhaust heat recirculation system is not inherently prone to coolant leakage; there was a bad batch, for whatever reason (poor crimp or weld), earlier year gen 4’s were failing.

And yeah, gen 3 have the system as well.

I “think” gen 5 has the EHRS too. It’d be interesting to know if Toyota’s separated with a flange, from the catalytic converter. With 3rd/4th gen they’re a single unit, a lot of eggs in one basket.

 

First, the more I thought about it, I realized the block itself is aluminum. So in theory, it could
possibly warp, though it's extremely unlikely because of the steal sleeves for the pistons.
The only time I've heard of any block being warps is when the engine was severely over heated.
Which yours was not, correct?

Unless you have a LOT of damage on the valve and/or seat, the material you'll be removing
will be very minute. You top of the valve is not getting hit like ones without hydraulic lifters, so again,
you won't have the damage like non hydraulic lifters.
You can inspect them, note there are "cap" on top of the valve. And if you gong to lap them in,
only do a second or two then check for an even like around the seat and valve. If it looks even,
clean off the grinding compound with carb clean making sure ALL of it is removed!

If you a larger leak, or several leaking, perhaps the machine shop would be the best idea.
They can only remove 1 or 2 thousands of the head if it's warped. Toyota say cannot resurface it.
That valve will be very close to that piston! Though it has been done, as some of reported.


Non of mine showed any wear, at 300,00 miles. (I'm at 385,500 miles).
Only 1 intake valved was barely leaking. It was showing just barely enough WD40 after 15-20 minutes of sitting.
I wasn't even sure if it was leaking or not.

Hopefully, the head is not warped and no valves are leaking. And the rebuild goes easily.

 

With no misfires or rattling I would diagnose first and teardown second.

Car Care Nut HG Borescope at 7:40

Bypassing the exhaust recirc is easy if needed and could be a diagnostic step.

Remove coolant hoses here and connect hoses together.



Gen3 Egr Cooler Flows



Exhaust Heat Recirc Basic Concept

 

This sounds more like a exhaust gas heat exchanger leak. Cars with bad head gasket will rattle and misfire upon startup and smooths out within a minute. That's with the coolant going down very slowly; like 100 miles before noticing a coolant drop.
FWIW; a coolant leak into the EGR system can also mimic a head gasket failure, but there should be intermittent misfires.

Any heat exchanger unit can rupture at anytime. You can't predict when your going to get a hole in your radiator - if they could; that would be a replacement item on your maintenance list.
A down and dirty test would be to simply loop-out the EGHE to see if that plugs the coolant leak. The car will still smoke a bit, until the residual coolant in the exhaust system is evaporated; but your coolant level shouldn't go down - if that's the problem. You can borrow a coolant leak tester device at any auto parts store too. This tool will only tell you if you have a coolant leak; NOT where the leak is.

Good Luck,,,,,,,,