Steamy Head Gasket Question

[JB83]

Well, I got the replacement '85 engine in my '83 SR5 to hold water and started her up. Vroom, firing on all four, no knocks or clunks, I was thinking so far so good, but after a few seconds I look in the rear view mirror and holy crap it was belching huge clouds of steam out the exhaust. My first thought--it's condensation in the exhaust system, let it work itself out. Then after a minute or so, still belching steam, it started running rougher, idling way down, then it shuts off abruptly. After the cloud of steam clears I looked back there and there's coolant in the tail pipe and on the driveway. Okay, so coolant getting into the combustion chamber = either head gasket or cracked head, is what I'm thinking at this point but please tell me if I'm missing something.

I took the (just-cleaned) plugs out. #1 and #2 were badly dry-carbon fouled. #3 and #4 were squeaky clean. I checked the torque on the head bolts: AOK. The oil still looks perfect. The radiator got hot, the coolant is clean, no bubbles when I opened it.

To do a test for blown head gasket seems pointless--seems to me I've got a coolant-to-exhaust leak and the head's got to come off. My problem is this: The project has already gone over budget. I'm a Spanish teacher and don't have stacks of money laying around. I need the cheapest solution possible solution that keeps me within good mechanical common sense as well. I've read as many head-gasket-related posts here as I could find.

Questions: I've read how some guys have just picked up the head (I'll be doing it with the same ceiling hoist I used to install the new engine so I can keep it where I want it once it's up), removed the old HG, cleaned the surfaces up, popped a new HG in, and torqued her back down. From what you guys have heard, in what percentage of cases has this actually worked out okay?

This seems like a very substantial leak and I'd like to rule out cracks if possible on my own. The flywheel on the new motor had a hairline crack, and after I spotted that I used the old one instead. I have an idea of what I'm looking for, and it sounds like it's between cylinders 3 and 4. The question is, if I've got a good bright light on it, am using a mirror to check various angles, am I likely to be able to see a crack?

Are cracked 3A-C heads fairly common? Worst-case scenario I still have the old motor and could pull that head for a reman (it had a blown head gasket--at least--too), but locally here at Napa it's about $500 after tax, before core charge refund.

Last question: What's the best way to shield/plug the cylinders / oil passages / water jackets from crud and to get the bolt holes clean (I don't have compressed air)?

Anyway, sorry this is so long. Thanks in advance for any advice for the cheapest possible solution...

[sdoan]

Bad news! I'm a teacher too

OK a couple apologies - this is really LONG and I've probably said a bunch of stuff you already know - sorry.

I had a bad head gasket and it would pressurize the cooling system. So this is how I checked it. Disconnect dist wiring (green connector) so engine doesn't start. Pull all 4 spark plugs. Fill cooling system and put overflow hose into clear jar of water so you can see coolant or air burp out. Crank engine on starter for 5 seconds or so. release pressure from radiator cap - no coolant or air should burp into jar of water. Put in 1 spark plug and repeat test. If it burps refill cooling system and put the plug in a different cyl to test that one.

I'd bet you're right and will find that there is a leak between #3 and #4.

I drove to Los Vegas and back on a leaky head gasket (it was not very leaky!) and the head was not cracked. The head gasket was part of a CHEAP gasket set (probably Chinese made). Pay for a good head gasket. I got a Felpro gasket from Schucks for about $30 and it's been fine.

When I replaced the head gasket I did not remove the manifolds or the dist. and the only gasket I replaced was the head gasket. You may want another exhaust manifold to pipe gasket though. It took about 6 hours at my slow pace to replace the head gasket - but I stopped for lots of breaks.

You don't have to pull the rocker shaft, the water pump or the lower crank pully. Suck out or soak up all the extra oil in the head so it is easy to see the head bolts and it does not drip oil everywhere when you lift it.

You will need a 3/8 drive 12mm deep impact socket to get to the head bolts (please check the size - doing this from memory). If the socket does not get by the cam on the driver's side center bolt, rock the cam slightly.

Stuff paper towels in the cylinder and an scrape the top of the block with a stiff steel scraper. I think I used a razor blade too. Clean and degrease with white gas. I did the same with the head. (I put the cyl head upside down on a wooden box the right size to support it without bashing the carb.) I spent a lot of time making sure nothing was left on the head or block. (also make sure it won't drip oil onto your clean surface when you put it back on).

Check the old gasket for the area of the leak, if you can find it. Make sure the head is not eroded at the site of the leak or between the leaking cylinders (feel with your thumbnail or use a steel ruler over the area). It's probably fine. Cracks usually form at the exhaust valve seat and usually run to the spark plug hole. If the aluminum is very clean it should show up as a black crack when you drip some dirty gasoline on it. I'd bet the gasket failed between cyls 3&4 (there are 2 small cooling passages very close to the edge of the cyl there) and that your head is not cracked.

Machine shops can flat check your head with a precision straight edge and feeler gauges. A good quality level or framing square might be used too - but check using both sides of the level or square in case it isn't exactly level or square. Toyota allows 0.002" warpage. It's probably fine unless you see evidence of overheating.

Torque the head bolts cold when you install the head. I always go back over them 2 or 3 times because I'm superstitious. Put the whole engine back together and ready to run. Now this is the important part. Retorque the head bolts with a hot engine (like adjusting the valves). Don't wait until the engine cools using some high minded rationalization like "Aluminum expands more than steel when hot so it makes sense to retorque cold." (ask me how I know ) The manual says retorque hot.

If you need the head rebuilt a machine shop can grind the valves for about $100. Call around. I took the machine shop the bare head with only the valves in it. The machinist disassembled the valves, cleaned, milled the head, ground the valves and seats and reassembled the valves for $100. A great deal. If you go this route, get a good quality head set (Cheap valve cover gaskets are too short and leak at the front, cheap head gaskets leak) and replace the cam seal.

Let us know how it goes.

[JB83]

It's official--Washington teachers rock. Thanks sdoan for your thoughtful response. I've written many a recommendation letter for students who went on to study at WWU--good school, and you live in a nice area. Mt. Baker in the fall when all the ground lichen etc. turns brilliant red/yellow/orange...unbelievable.

My valve cover gasket and exhaust flange gasket are brand spankin' new, so hopefully I can get away with just a HG. I'll do the work over the next week per your suggestions and the other great stuff I've read here and get back to you when I crank her back up. Thanks again!

[xirdneh]

I wonder if it is neccesary to re-torque the 3ac engine head bolts with a hot engine.
I usually use Felpro head gaskets and if I remember correctly they do not recommend re-torqueing
Anyways I have done at least 7 head gaskets over the last ten years on the tercel 3ac engine without re-torqueing
None have failed so far
I could not find anything in my 1983 FSM about re-torquing hot
Is it really in there somewhere?

[Petros]

I have done this job several times. it is not too bad difficult of a job (scraping off the old head gasket is the worst part). I only bought a new head gasket (about $20) each time. If you leave the int/exh manifolds on it you only have to break it at the head pipe (which may need a gasket too, but I have reused mine). It also goes faster too by leaving the manifolds on.

Cracked heads are pretty rare with Toyota. I have really fried mine several times (I blew a hose off once, and had the radiator blow out another time) and though it was badly warped there was no cracks. There are dye kits you can buy to do a check your self. A visual inspection will not likely locate cracks unless they are really bad. You spray dye on the cleaned parts, and wipe off the surfaces, then you spray a "developer"on it, any dye in the cracks become visible. A machine shop does not usually charge much to do a crack check if you are concerned. Or you can take your chances and skip the crack check, I have done that before too.

There are several things you should check when the head is off, that is to verify the head surface is flat (after you clean it off of course) and inspect the valve face surfaces. It is best to rent or borrow a valve spring compressor, but it can be done with out it (though I would not recommend it). If the valves are not too bad you can just lap them into the seats with compound rather than do a whole valve job. If it needs a valve regrind there is no inexpensive way to do this, you might consider removing the other head and see if the valve seats are in any better shape.

When I was a student and had no money to redo my valves, I bought heavy valve lapping compound (it is an abrasive paste) and used a drill motor on the stem and let the compound reface the valves and seats. The results was not pretty, but it sealed the face and ran good. It is also possible to surface the head the same way if you have a large flat surface to slide it over (like a slab of polished granite, I have a left over piece of counter top I use for this). If the head is badly warped it should be machined, which fortunately does not cost too much. If the head needs to be machined you will have to remove the manifolds, which means you will likely have to replace that gasket too (though I have reused those too if it is not torn or bent).

You can clean off the gasket face and the bolt holes using spray carb cleaner, and a small bore brush (available at the auto parts store). The most time consuming part of a job like this is actually cleaning all the parts, you can do a decent job with odorless paint thiner and then use the spray brake parts cleaner for the final cleaning. Use lots of paper towels too. And make sure the surfaces are clean before you install the head. Use thread lube on the head bolts (or light grease) and follow the torquing procedure in the FSM. Also, when dropping the head on, watch out for that little water pump by-pass tube!

Good luck.

[sdoan]

Anyways I have done at least 7 head gaskets over the last ten years on the tercel 3ac engine without re-torqueing
None have failed so far
I could not find anything in my 1983 FSM about re-torquing hot
Is it really in there somewhere?

Cool, if I'd used a good quality Felpro gasket I may not have needed to retorque either. But I used the toilet paper POS that was in the gasket set, retorqued it cold, and still had to replace it!

So I'll be retorquing hot from now on...

Page EM-37 in the 1983 FSM:

#26 Start Engine
Warm up the engine and inspect for leaks.

#27 Perform Engine Adjustment
(a) Retighten the cylinder head bolts (40-47 ft-lbs)
(b) Readjust the valve clearance.
(c) ignition timing
(d) idle speed

[keith]

To check for cracks, you need a product called "magnaflux". You could find this at an industrial supply house. I think you can do the same thing with automatic transmission fluid and talcum powder. Wipe the transmission fluid all over the head, then wipe it as clean as you can with a rag. Then shake on some talcum powder. The transmission fluid will penetrate into any cracks and the talcum powder will make it show up as red lines. I'm not a 100% sure it will work but you could try it.

[JB83]

Yesterday afternoon I took the valve cover and head off the old engine, because I want to save that head, and to get some idea of what the HG job on the new one in the car will be like. The old engine had a blown HG plus unknown possible issues from pistons down. Definitely some green beads of coolant and some mocha latte gunk under the valve cover, and that one head bolt did indeed need the skinny deep 12mm socket and some cam jiggling to work the socket down onto it, so I was glad I'd picked one up on the way home. Also three of the bolts had corrosion and hard crap in the threads, which cannot have been good for getting an accurate torque. This afternoon I'll scope that head out for warpage and valve issues and get ready to pull the one off the newer engine. Got a Felpro HG waiting for me at the parts store on my way home.
Tons of useful info here you guys, much appreciated!

[Petros]

Where are you? If you are lucky enough to have someone on the list nearby, perhaps they can drop by to give you a hand and more tips if you need it.

[JB83]

I'm down in Gig Harbor, out in the sticks a ways, across the Narrows Bridge(s) from Tacoma. Good to know there are other T4WDers in the Puget Sound area, at least four I've seen so far. I'm hoping to get this car mechanically sound (it was not running, left under a tree for a year, full write-up in member profiles), sometime after I get back from Argentina. Leaving Thursday on a two-week trip with 16 students and another teacher. First time to Argentina, I usually take them to Spain but the dollar's taking a beating over there now. Anyway, more soon on the HG!
Jim