Sorry if this is not the proper way to ask this but recently the head gasket blew on my truck. My mechanic checked it out and told me I'm looking at about $2000 CAD to get it repaired. I called a few other places to see what their prices are and they are all around the area if not more.

I decided with being laid off I have nothing but time to do this repair myself.

Have any of you guys done this? Any tips? Anything else I should do while I'm in there?

Thanks.

 

Welcome to the forum

Its mostly just wrench work, but quite a bit of it
Expect 1 full day in tear down, to get heads off
Then 2 or 3 days of heads being at machine shop, unless you just buy new heads
And then a full day putting it back together

A machine shop needs to clean and pressure test the heads, a cracked head is VERY common on the 4.0l OHV engine(1990-2000), very common, and same symptom as blown head gasket, exactly the same
So if you want to reuse the heads then they MUST BE pressure tested
And then if OK, they need to be surface, made flat, in case they warped a bit

Take lots of pictures during tear down so you know where wires and vacuum lines plug in, they are FREE, lol
I have a long table I use when doing disassembly, as parts come off they go at the end and then work their way to the other end, so I don't end up putting something on and then realize I have to take it back off because another part needed to go on first, lol

You will need metric sockets and wrenches
A T-55 torx for the head bolts
And a torque wrench to re-install them

You need:
A head gasket Kit, comes with the new gaskets you will need, also comes with 12 valve guide seals that are good to give to machine shop to install, if you go that route, you need a valve spring compressor to install these
You also need a set of new head bolts, these bolts are TTY type so can not be reused
Oil and filter
Coolant

The exhaust manifold bolts are the hardest to deal with, you can spend HOURS on 1 or 2 of them
If there is an exhaust shop near you and vehicle drives, you may want to call them and tell them what you are doing(replacing head gaskets) and ask if they can loosen and "snug" back up the exhaust manifold bolts and header pipe bolts, and replace any broken ones
And "how much" for CASH
Most I ever paid was $80, least was $25
They have all the tools and know all the tricks to get out rusted in place exhaust bolts

Drain coolant first
Don't drain the oil yet
After heads are off you will need to clean up block surface and piston tops, and some of this debris will go down into the oil pan, and sit in the oil
After clean up is done you can drain the oil or even wait until heads and lower intake is back in place, then drain the oil
And pull off the filter

The 4.0l OHV can get failed lifters, they make a "ticking" noise, and they can only be changed with Heads OFF, but its a judgement call to put in new ones
I usually don't, but I am cheap, lol

There is no special "knowledge" need for this repair, just take your time and use common sense
The torque pattern and specs for the heads bolts can be found on-line, you have a Ford 4.0l OHV engine
For exhaust and intake as well

Make it easy for you to work on, I am taller so don't mind the height of engine bay, but if its too high then jack up front and remove the tires, then lower it down on blocks or ?? to make it easier to work on


Head gaskets don't just blow, and heads don't just crack, out of the blue

So do you know why this happened, and is that problem solved?

 

Holy smokes that's quite the response. It's very appreciated. I have only had the truck for a year so no clue why it blew. A mechanic I know never mentioned pressure testing the heads only checking if they are level.

 

Pretty much any machine shop will pressure test a head before they surface it, make it flat, or its a waste of their time and your money, lol
So maybe mechanic thought you knew that, but not sure why he would

If you need or want new head(s) then they must be 1998-2000 4.0l models, part is 98TM head, can't use the older model numbers

Why did you take it to the mechanic?

Was it overheating?

 

It started to overheat (about 60% of temp gauge) but I shut it down then noticed rad was low and mechanic confirmed it was head gasket

 

Well overheating is a sign of a head gasket leak, or cracked head, but............................
These are CAUSED BY overheating i.e. a coolant leak, and you drive it not knowing coolant is low

But you really have to run it well above 60% for a few minutes(10+ minutes) to blow head gasket

How it works
Metal expands when heated, same as liquids do, as you heat up cold engine the block and head metal expands, and since they are bolted together they expand towards each other with the head gasket in between
The head gasket is designed to take this expansion and contraction(cool down) over many many cycles without leaking, very cool it can do this, lol

If you run low on coolant, or thermostat doesn't open or water pump should stop working, the Heads get the hottest because they are at the top, and their metal expands even more the hotter they get
They can expand to the point where they CRUSH the head gasket causing it to leak, or metal expands too far and CRACKS the metal in the head
This is from overheating, so doesn't just "happen" out of the blue


Why it causes overheating AFTER it's blown or cracked:
Each cylinder has 1,000+ PSI pressure when it fires, a blown head gasket(or cracked head) allows some of that pressure to travel over to the cooling system, cylinders are all surrounded by cooling passages, point of the cooling system.
This pressure is air(well exhaust gases) and it forces coolant out of the way, cooling system only has 14psi so no contest, lol
As this "air" builds up in the cooling system engine will start to overheat because "air" doesn't cool as well as a liquid
The coolant overflow tank will also FILL UP with coolant, because the air is pushing it OUT
Then the overflow tank will start to bubble up "air" because the "air" from the leaking cylinder has traveled to top of radiator and is being pushed out by new "air" coming in from the head

You can confirm the blown head gasket/cracked head diagnoses with a simple test
One thing you can do first is to smell your overflow tank, if it smells like exhaust then yes you have cylinder "air" leaking into cooling system, or smell radiator air

The glove test
Get a latex glove or plastic bag, like a sandwich bag, condom also works, lol
A rubber band

Cold engine

Unplug coil pack's 4 wire connector, so no spark, no start
Take off rad cap, Coolant in rad should be down at least an inch for test, down farther is fine, if its at the top drain some out

Take off overflow hose, you need to cap this port in rad, gum, putty, vacuum cap off engine, ??
Put glove or bag over cap opening and seal it with rubber band

Cooling system is now sealed

Crank engine over and watch the glove/bag
It should just lay there
If it starts to BOUNCE that means pressure is leaking in to cooling system from blown head gasket or cracked head

If it bounces you can ID which cylinder is leaking by removing 1 spark plug at a time and cranking engine again
Glove/bag will stop bouncing when leaking cylinder's spark plug is removed, because no more pressure is being pushed in

If glove doesn't bounce, then plug coil pack's 4 wire connector back in
Start engine
Glove/bag should NOT start to inflate, if it does you do have a smaller leak, but it will get bigger over time

If no bounce and no inflate then you do not have a blown head gasket or cracked head

There are many other reasons for a vehicle to overheat, thermostat, radiator, water pump, ect................

 

Do you know the exact part number or the specifications for the exhaust manifold bolts/studs for the 99 4.0 ohv bc a guy I work with said if it's to long it might cause some damage.