4.0 head removal

Greetings
After investigating a coolant usage (~1 quart every 2 - 300 miles) it looks like I have a leak at both the L & R head gaskets. I ran the block test but it did not show any exhaust gases in the coolant, even though the usage seems excessive for the leakage I see. I read "97 Ranger XLT" article per replacing valve cover, fuel rail & lower intake gaskets (which was excellent). Now I need to remove the heads and was wondering if leaving the exhaust manifolds on or removing them is the way to go? The bolts going to the Y pipe are very rusted and I not sure I will be able to remove them. Getting heat to the right side ones could be a problem with the oil filter bracket there. This is a 96 Ranger XLT 2 WD with a 4.0 motor. It only has 55k miles and I bought it from the original owner. Thanks for any and all help
Gary

Symptoms of head gasket or cracked head start with overflow tank getting passed the "full" mark(over filled), engine temp gauge can go up and then drop back to "normal", heater will go cool then warm again.
All this is because the high cylinder pressure is pushing "air" into the cooling system, this "air" displaces coolant which is forced out into the overflow tank, the "air" also gets into the heater core and will block coolant passage until it is pushed out.
Coolant can also be pulled into a cylinder and then burned, this causes a whitish "smoke" from the tail pipe and it will have a sweet smell.
When enough coolant is displaced engine will start to overheat and not drop back to normal temp


You can try the "Glove test" it is free and works well to ID cylinder to water jacket leaks, you can even ID which cylinder is leaking.

Cold engine
Works best if coolant in rad is about an 1" or more down from the top, because if there is a leak it will push coolant out into Glove, so drain a little coolant out if needed.
Remove rad cap and overflow hose
Plug overflow outlet, vacuum cap or hose with bolt in it works
Place Latex glove over rad cap opening and seal with rubber band, a balloon works as well, even seen a condom used for this
Cooling system is now sealed

Pull off connector on coil pack, we want a no start

Push gas pedal to the floor, this turns off fuel injectors(optional)
Crank engine and watch glove
Glove will bounce if there is a leak to the water jacket, there is 150+psi of pressure in each cylinder on it's compression stroke.

If glove bounces, remove 1 spark plug at a time and crank engine, when glove stops bouncing last spark plug removed was from the leaking cylinder, put spark plug back in to confirm.

If glove doesn't bounce then there is no leak or cracked head.


My 4.0l had the overflow hose passing over the top of the rad to the overflow tank.
It cracked on the section above rad.
When engine warmed up and the warm coolant expanded and was sent to overflow tank, as normal, it would leak out the cracked hose and onto the warm rad, so evaporated before dripping to the ground.
When engine cooled air would be sucked in instead of coolant from the overflow tank.
So I was losing coolant but could not find a leak, even pressure tested the system.

So check overflow hose.


Exhaust manifold bolts can be stubborn, and drivers side hard to get to, I have removed the 2 nuts on the exhaust pipes and pulled heads with manifold attached.

I have a local muffler shop that I have taken vehicles to and they will remove all the exhaust bolts I will need to deal with and then replace any that broke or had marginal heads, then reinstall them but snug not tight.
Most I ever paid was $80, and they had to replace several bolts and studs/nuts on that car.
They know all the tricks and have all the tools, broken or stuck bolt might take them 1/2 hour to replace, it would take me 2 or 3 hours and maybe 2 trips to parts store, lol.


4.0l heads crack between valve seats, it can be hard to see if it just started to crack, have heads surface and pressure tested at machine shop, also have them replace the valve guide seals if you don't have a spring compressor, new seals will come in head gasket set.

Keep push rods in order, top and bottom and cylinder order.

head bolts can not be reused.

Before putting valve covers back on, install Cam position sensor synchronizer if it was removed, easier to see when #1 is at the correct TDC mark

What makes you think it is the heads and not the intake manifold? The intake can leak coolant into the cylinders. Like Ron said, if it passes the glove test, you need to look elsewhere for you coolant loss.

Ran the glove test yesterday, it did not move. Block test was negative from the previous day so I guess I don't have a head/gasket problem. Will continue looking. Any test for an intake leak? thanks for your help to date. Gary

You can rent a cooling system pressure tester, usually about $20-$25 for the day.
It is a device that goes on the rad cap opening with a pressure gauge, and a hand pump.
You pump system up to 20psi(16-18psi is normal warm engine pressure) and then see if pressure starts to drop, if so you have a leak.
If not you don't.

If you have a leak searching for it on a COLD engine is much easier, and with pressure in the system it will leak more coolant so easier to spot, keep pumping up the pressure as it drops.
And don't forget to check passenger floor for dampness, heater cores can leak.

If you have a leak (pressure loss like Ron said) and still can't find it. With the pressure tester pumped up, do a WOT test for say 30 seconds, so engine won't start, and then pull the plugs and see if one if one of them is wet with coolant. If so then, as far as I know the only way left for it to get into a cylinder is the intake.

The overflow tank will crank along the bottom commonly. A little silt in the bottom will slow the drip to the point it's hard to find. It happened to me...was hard to figure out and I did a lot of checking like has been suggested.

woodyedmiston said:

The overflow tank will crank along the bottom commonly. A little silt in the bottom will slow the drip to the point it's hard to find. It happened to me...was hard to figure out and I did a lot of checking like has been suggested.

Click to expand...

This. I've had two crack right where the arm (?) on the back of the tank sits into the slot on the fender. I got creative with superglue and a soldering iron in both cases. No more leaks. (Yet)

First thing this morning I ran a pressure test on a cold engine. Held 20 lbs for 5 minutes, needle did not move. While this was still connected I ran the WOT test for 40 seconds and did not see the needle move off the 20lbs. Should I run this on a warm engine? I then closed off the hose to the overflow tank and ran 5lbs of pressure on the overflow tank for about 2 minutes, no leaks. I'm going to give this some more thought over the next few days and also measure how much coolant I am loosing. Gary

Good work, but no leaks.......hmmmmm

More likely to have leaks on cold engine, metal expands when warm so can seal a leak.
Warm engines do leak more coolant but that's because they have pressure from warm coolant expanding, the pressure tester does that part on cold engine.

Running engine test indicates no cylinder to cooling system leaks.

Maybe a neighbor or your wife is "gas lighting" you, lol
Draining a little coolant after you fill it

All I got left is a bad radiator cap. They have been known to do weird things. Like leak just enough to lose coolant; but, not enough that you can see it.

I checked the coolant yesterday after driving the truck for a week and putting on 135miles, I had lost ~12 ounces. Something odd I have noticed is that if I start the truck up in the garage and let it run I don't smell the coolant, I only seem to smell it after I drive it. Going to try and pay more attention to this going forward. I did put a new radiator cap on yesterday and prior to this post I have replaced the radiator and heater control valve both of which I saw coolant seeping from. Thanks for all the help and suggestions so far. Gary

Where do you smell the coolant? Engine bay? Exhaust?

Does the coolant level in the overflow tank go up and down like it should?

When truck is completely cold mark the coolant level in the over flow tank with a a crayon. Drive the truck like normal until warm (hot). The level in the overflow tank should be higher, say an inch or more (mark that level). Let it get completely cold again. The level in the overflow tank should now be back to the first mark you made.

If it is lower you either burped air out of the system or you lost coolant from a leak that is not showing on the ground or engine. Add coolant to the radiator and overflow tank (to the line) and retest. Keep testing until you find the leak. There is a dye you can buy to put in the coolant that will leave tracks where it is leaking.

If it is at the second mark you have forced coolant out of the radiator with normal heat expanding the coolant and the recovery system (radiator cap, cracked overflow line or cracked overflow tank pickup) is not working correctly to suck it back into the radiator. Or air is being sucked into the system through the leak during cool down.

Or, air is being pumped into the cooling system forcing fluid into the overflow tank (small head gasket leak??). So you need to test for combustion gas in the coolant using a Combustion Leak Test Kit. Google how to do that, it isn't hard; but, needs to be done correctly. You will, of course, need to beg, borrow or buy the kit.

Earlier you said it passed the glove test; but, I'm not convinced that a real small leak would show up with that test.

Report back!!

Besides the glove test I ran the block test where vapors from the radiator are sucked through a blue liquid while the truck is running. Tried this on the radiator and the overflow tank and neither time did the blue liquid change color. Just to make sure the test was valid I tried the test at the exhaust pipe and within seconds the liquid turned yellow.
I have been monitoring the level in the overflow tank per your note and the level changes just as you would expect, higher when running, lower as the engine cools. The only problem is that the cold level in the tank keeps getting lower each time.
I always smell the coolant in the engine compartment and have not smelled it at the exhaust pipe yet. Now that the weather has warmed up and I have the drivers window down while driving I can smell the coolant when I pull up to a stop sign or red light.

Well, I wrote a response and it disappeared. So again.....

What you know:
Head gaskets are good. She passed the gas test.
No coolant smell in exhaust, so no leaks into to the combustion chambers.
No coolant smell in the cab, so the heater core is good.
No visible leaks on the engine or hoses; but, you can smell it. .

But, since you pressure tested the system and it holds pressure anything I say is a longshot since it is using so much coolant!! Anything I say at this point is a longshot and is just guessing.

So, if is a small leak, so small it evaporates before the hits the ground or runs down something it would be very hard to find. But, since it is big enough to use a significant amount of coolant it should be visible. I think you said it loses 12 ounces every 200 miles. A quart every 300 miles is a heck of a lot. It only holds around eight quarts. So I would think you could see it. It should also fail the pressure test.

Radiator seam (longshot, especially since you pressure tested the system)? I had a little leak in my B2200 and it was on the bottom of a seam and it took forever to find because it held pressure pretty good. But, it only used a couple of ounces every week or so.

Core plugs? There are like 9 or 10 of them. . Look for corrosion around them. There is one or two on the back of the heads. One, I think is on the back of the block behind the bell housing. If that one was leaking the coolant would drop off the bottom of the transmission (if it is big enough to drip). That would be a big bummer!!!

At this point I would (me, just me) try some GM type stop leak. This stop leak is made up small fibers and will not plug up anything. It was used by GM at the factory to seal some Cadillac head bolts (a bad design where the bolts when into the water jackets and leaked coolant, it was later corrected by a design change). It used to be a dealer item; but, I don’t know if is still available from them. Google it!!

I am out of ideas, so you need someone smarter than me. Good luck!
Ed