1991 4.0 antifreeze in exhaust

[tekkatekka]

I have a 1991 ford ranger 4x4, 4.0 v6. 190,000 miles. Runs great and even gets 18-20 mpg on hwy trips with a 1200lb camper. I have been using small amounts of antifreeze for the passed year with no leaks. Lately much more, sometimes a 1/4 gallon in 400 miles. 4,000 miles ago was having a miss and changed the plugs that had 30,000 miles on them. Miss went away but came back 2000 miles later. Changed plugs again and wires and miss went away. Now about 1000 miles later no miss but using more antifreeze. The plugs each time looked pretty good. The last time, when I changed the plugs and wires, it started blowing a lot of white smoke on initial start up for at least 30 minutes at idle, then just water dripping off the tail pipe. It did that a few more times and then stopped. When it sits for a few days I can see the smoke on start up for a few minutes only. I just took a 400 mile trip with the camper and it ran great except for the using antifreeze. I took a compression test and they are all within 7 lbs of each other. I did a block test using the blue fluid in the proper tester to check for exhaust fumes in the air in the radiator. The fluid turned green, while it is suppose to turn yellow if exhaust is present in the radiator. My first thoughts were head gasket but after reading some forums I am wondering if it could be intake manifold gaskets. I am not sure about the configuration of the water and intake ports. I also see bubbles when I look into the radiator when I have drained some fluid off to see in, especially when I increase the rpm's I can see small bubbles from below. I am not sure if they are just coming from the water pump?
So....Is there any way to know if the antifreeze is coming from either of the intake gaskets or the head gasket or a cracked head? If it was a cracked head or head gasket I was thinking of trying a sealer, steel seal. If that didn't work then I was going to tear it down. Any advice would be apprecitated.

 

[Gilbee01]

It could be a head gasket ( white smoke) but also you engine has a few miles on it .. Before taking everything apart I would suggest using the radiator as a starting point and follow every tube to and from the engine.. If still fluid loss look into a head set of gaskets . Try to narrow it down before taking this on. I personally don't like the seal in a bottle stuff . If its that big of a problem just rebuild the engine and have a fresh start.


-gil-

 

[alwaysFlOoReD]

Another member [IIRC RonD] on here has a good test for leak into rad system; use a rubber glove sealed with tape on the neck of the rad and start the truck the glove will move if there's a leak.
There's also using a vacuum gauge to isolate problems, search for procedure.
And last I can think of is a leak-down tester. It uses a measured amount of air into the cylinder at TDC and compares two gauge readings. You can then listen at exhaust, intake, pvc or valve cover, rad for air leaking. Again search for procedures. Along with a regular air compression reading you will then have a very good idea of your motors condition.
Good luck,

Richard

 

[tekkatekka]

I have checked all the water hoses and no leaks. I also redid a block test for exhaust fumes in the radiator using the blue fluid that will turn yellow if exhaust fumes are present.
It stayed blue the entire time which means no exhaust in the water jacket. I am wondering if it is just the intake manifold leaking and dumping antifreeze into one or more cylinders and that would mean no exhaust coming into the water jacket. Any ideas to test if it is the intake manifold?

 

[Lil-Pony]

Smell inside the intake for rad, fluid? Stupid answer but just a thought

 

[RonD]

Could be intake gasket is leaking coolant internally and that is being pulled into a cylinder and burned(white smoke), or even a cracked intake.

Compression test wouldn't show a small leak, if it was large enough to show on a compression test you would be overheating like crazy, and overflow tank would be overflowing.

Block test is OK, but not 100%.

You can rent a pressure test kit for the cooling system, a rad cap with a gauge and hand pump, you pump it up and then watch the pressure, if it starts to drop then you know there is a leak.
But you kind of already know that, just not where the leak is.

Now if you had this pressure test kit hooked up and had, say 10psi of pressure on the gauge, and then had someone turn over the engine(no start, disable spark), you might be able to see if it was a head gasket/cracked head issue, gauge would pulse up as cylinder pressure is pushed into the cooling system.
That's the basis of the glove test.
If there was no pressure being added by the cylinders then I would pump up the pressure in the system and then listen at the intake, maybe even pull the 4 corner spark plugs and use a rubber hose to listen inside each one, rotate engine(open intake valves) then listen again

Water pumps don't make bubbles, they are circulating pumps not pressure pumps.

Water out the tail pipe is normal; when you mix gas with air and then ignite it, you get some water vapor as the result, which is why exhaust system rust from the inside out
But white smoke is different, especially if it is not cold outside.

The glove test should settle things for you and it is free, well almost free you do need a latex glove or balloon.
Cold engine
Remove spark plug wires, we want a no start
Remove rad cap
Remove overflow hose and plug that hole, vacuum cap from engine or short hose with bolt in it works.

Place glove(balloon) over rad cap opening and seal it to the neck with rubber band or tape, glove should just be laying there.
Cooling system should now be air tight.

A cold cooling system has no internal pressure, the pump circulates coolant it doesn't add any pressure.
A cooling system gets pressure when the coolant gets hot, about 180deg, and starts to expand, so no pressure in a cold system.

Turn over engine
Watch the glove, if it moves you got a leak from a cylinder into the cooling system.
And it will pulse each time that cylinder comes around to it's compression stroke.
If you want to find out which cylinder, just remove one spark plug at a time then turn over engine, when glove stops moving you found the cylinder.

My 4.0l had good compression and same symptoms, had a cracked head, #4 cylinder had a crack between the valve seats.
#4 had higher compression than 2 other cylinders, it was at 165 and had 2 other at 160 and the rest at about 170

 

[Gilbee01]

I think that year had issues with heads cracking a lot .. More than likely that is the culprit .


-gil-

 

[tekkatekka]

UPDATE. Thanks for the replies and thanks Ron D for the details on using a Rad pressure tester. I used the Rad pressure tester up to 20 lbs after the engine reached operating temperature. It held for over 30 minutes. I just read Ron D explanation of using glove or rad tester and turning over engine. I will do that next and see what happens. I hooked up a vacuum gauge, teed into the line from upper intake manifold to brake booster. I am at 5000 feet altitude so deducted 5 from all the results of the tests I read about online. Everything seems totally normal with vacuum. Needle is steady at 16 at idle, 17 steady at 1800 rpm and 2500 rpm. At 2500 rpm for 15 seconds and release throttle it climbs to 19 and then back to 16. If intake manifold gasket is leaking would it show up in vacuum test? If bad head gasket, is it possible that antifreeze is getting into combustion but combustion is not getting into cooling system, it's just traveling one way?? I spoke with the Ford dealership and they said it could be a cracked thermostat housing or leaking sensors in the area or water pump. I don't understand how a cracked thermostat housing or water pump could allow water in combustion.
update:I just hooked up the radiator pressure tester to the cold engine and disarmed ignition and pumped tester to 10 lbs. I turned over the engine 5 times at 10 seconds each time and the needle did not move?

 

[tekkatekka]

Could be intake gasket is leaking coolant internally and that is being pulled into a cylinder and burned(white smoke), or even a cracked intake.

Compression test wouldn't show a small leak, if it was large enough to show on a compression test you would be overheating like crazy, and overflow tank would be overflowing.

Block test is OK, but not 100%.

You can rent a pressure test kit for the cooling system, a rad cap with a gauge and hand pump, you pump it up and then watch the pressure, if it starts to drop then you know there is a leak.
But you kind of already know that, just not where the leak is.

Now if you had this pressure test kit hooked up and had, say 10psi of pressure on the gauge, and then had someone turn over the engine(no start, disable spark), you might be able to see if it was a head gasket/cracked head issue, gauge would pulse up as cylinder pressure is pushed into the cooling system.
That's the basis of the glove test.
If there was no pressure being added by the cylinders then I would pump up the pressure in the system and then listen at the intake, maybe even pull the 4 corner spark plugs and use a rubber hose to listen inside each one, rotate engine(open intake valves) then listen again

Water pumps don't make bubbles, they are circulating pumps not pressure pumps.

Water out the tail pipe is normal; when you mix gas with air and then ignite it, you get some water vapor as the result, which is why exhaust system rust from the inside out
But white smoke is different, especially if it is not cold outside.

The glove test should settle things for you and it is free, well almost free you do need a latex glove or balloon.
Cold engine
Remove spark plug wires, we want a no start
Remove rad cap
Remove overflow hose and plug that hole, vacuum cap from engine or short hose with bolt in it works.

Place glove(balloon) over rad cap opening and seal it to the neck with rubber band or tape, glove should just be laying there.
Cooling system should now be air tight.

A cold cooling system has no internal pressure, the pump circulates coolant it doesn't add any pressure.
A cooling system gets pressure when the coolant gets hot, about 180deg, and starts to expand, so no pressure in a cold system.

Turn over engine
Watch the glove, if it moves you got a leak from a cylinder into the cooling system.
And it will pulse each time that cylinder comes around to it's compression stroke.
If you want to find out which cylinder, just remove one spark plug at a time then turn over engine, when glove stops moving you found the cylinder.

My 4.0l had good compression and same symptoms, had a cracked head, #4 cylinder had a crack between the valve seats.
#4 had higher compression than 2 other cylinders, it was at 165 and had 2 other at 160 and the rest at about 170

This morning on a cold engine I tried the glove technique on the radiator on a cold engine. As my last 2 posts say I have tried it with a rad pressure tester and no change. With the glove this am I turned over the engine about 15 seconds and gradually some of the fingers in the glove filled with air. Is this coming form the cylinders or could it be just the water pump is causing some expansion?? and why didn't it show up with the rad pressure tester?

 

[RonD]

Remove all the spark plugs next time and retest.
If glove doesn't start to inflate then you'll know cylinders were the source of pressure.
If it still inflates then you'll know it's normal system pressure, but at cranking speed the water pump isn't turning all that fast and so isn't displacing much water, and t-stat is closed so any water pump pressure should be towards the engine not rad.

If there is a cylinder leak it isn't a big one or you would get overheating as engine "air" displaced coolant.
It might be that with pressure in the cooling system the leak is minimal, and when engine heats up it is closed(head and block metal expands).
As engine cools off(cylinder pressure is 0) the cooling system's 16psi pushes some coolant into the cylinder and you get the white smoke on startup.

How long did you do the pressure test on the cooling system?
A cold system should hold pressure for hours, coolant is not expanded so won't shrink, so pressure should just stay at the same level for a long long time........unless there is a leak.

 

[tekkatekka]

Remove all the spark plugs next time and retest.
If glove doesn't start to inflate then you'll know cylinders were the source of pressure.
If it still inflates then you'll know it's normal system pressure, but at cranking speed the water pump isn't turning all that fast and so isn't displacing much water, and t-stat is closed so any water pump pressure should be towards the engine not rad.

If there is a cylinder leak it isn't a big one or you would get overheating as engine "air" displaced coolant.
It might be that with pressure in the cooling system the leak is minimal, and when engine heats up it is closed(head and block metal expands).
As engine cools off(cylinder pressure is 0) the cooling system's 16psi pushes some coolant into the cylinder and you get the white smoke on startup.

How long did you do the pressure test on the cooling system?
A cold system should hold pressure for hours, coolant is not expanded so won't shrink, so pressure should just stay at the same level for a long long time........unless there is a leak.

I let the pressure test go for 30 minutes on a cold engine. Here is my last post about that and a vacuum test, please let me know if you have any comments on that.
Thanks for the replies and thanks Ron D for the details on using a Rad pressure tester. I used the Rad pressure tester up to 20 lbs after the engine reached operating temperature. It held for over 30 minutes. I just read Ron D explanation of using glove or rad tester and turning over engine. I will do that next and see what happens. I hooked up a vacuum gauge, teed into the line from upper intake manifold to brake booster. I am at 5000 feet altitude so deducted 5 from all the results of the tests I read about online. Everything seems totally normal with vacuum. Needle is steady at 16 at idle, 17 steady at 1800 rpm and 2500 rpm. At 2500 rpm for 15 seconds and release throttle it climbs to 19 and then back to 16. If intake manifold gasket is leaking would it show up in vacuum test? If bad head gasket, is it possible that antifreeze is getting into combustion but combustion is not getting into cooling system, it's just traveling one way?? I spoke with the Ford dealership and they said it could be a cracked thermostat housing or leaking sensors in the area or water pump. I don't understand how a cracked thermostat housing or water pump could allow water in combustion.
update:I just hooked up the radiator pressure tester to the cold engine and disarmed ignition and pumped tester to 10 lbs. I turned over the engine 5 times at 10 seconds each time and the needle did not move?

 

[RonD]

Must have missed that post.

Reads as OK, cold test is best for that, metal has shrunk down so any gaps are bigger.


Coolant is disappearing, but without visible leaks, cooling system pressure test shows no pressure leaks.
So where else can coolant leak..........overflow hose and overflow tank.
Overflow hose runs across the top of the rad so coolant leaking there would evaporate so no sign of leak, check for cracks in that hose.
Blow in the end of the hose to test for leaks and block overflow tank opening to see if it holds pressure in the tank as well, small crack in the tank at the "hot level" could be leaking only when engine warms up and adds coolant to the tank.

Heater core connections and bypass hoses can leak onto exhaust so no signs of leak under truck, but pressure test should have IDed than, was heater valve open during pressure test, shouldn't matter since pressure is equal on the open hose, but what the heck .

None of this gets coolant into a cylinder.

So maybe there are two things at work here, unrelated but look related, i.e. coolant disappearing and white smoke at startup.
Where are you getting your gas?
Could there be a higher moisture content, this would build up more than normal water vapor in the exhaust system, it condenses in the exhaust system when its shut off and then turns to steam when restarted.
Or has the humidity level been high in your area, same thing can occur, moisture in the air the engine is using means more in the exhaust system.
Smell the white smoke, anti-freeze has a distinctive smell, can't miss it, if your not sure then it's not anti-freeze burning.