Hey everyone, my names Nick. I am new to the forums and just bought a ranger a couple weeks ago. I commute about 250 miles per week. I just bought a 1999 4.0L XLT with I think about 6 inches of lift, new Cooper Discover AT3 tires, a roll bar with 4 off road lights, brush guard, and stinger bar/winch bumper.
A couple weeks ago (around when I first got the truck) I changed the front brakes that were completely gone and the oil. No big deal. I had everything done in about an hour. I jacked up the front end at the "axle". I dont really know what that thing is called but I call it an axle (its ok, I know Ill get some flack for it) I just hope it is ok to do that. I typically jack up my vehicles at the front and rear axles.
About a week after that I notice about 2 tablespoons worth of coolant on my garage floor. I looked at the whole engine compartment and could not find any type of leak. Earlier today I revisited this and I found the drivers side lower part of the engine was very slowly dripping out coolant. My reservoir has drained a very very small amount (maybe 1/8th of a cup if that). Is this the lower intake manifold gasket? If it is, how hard of a fix would it be if I did it (Im no mechanic by any means, however I can do "mid-level" auto work)? If I cant do it, how much should something like this cost at an auto shop?
As a side note, the trucks temperature gauge does not work inside the cab. I do however get good heat and A/C and I have no issues with overheating or under-heating. My gas mileage is currently at about 20-21 mpg highway. I also have no coolant in my oil (as far as I can tell). There is no milky white film or smell of antifreeze in the oil either. My exhaust smells completely normal as well, no scent of antifreeze. There are also no plumes of white smoke coming from the engine compartment. The engine runs completely normal with no weird noises when accelerating or decelerating.

Who knows, maybe Im obsessing over nothing, but I figured I would ask you guys and see what you think.
Thanks
Nick

 

Lower intake leak would be at the front or rear of the engine.

Best bet is to rent/get a Cooling system pressure tester.
These attach to the rad cap opening and have a gauge and a hand pump.
It allows you to pump cooling system pressure up with a COLD engine, and then look for leaks.
Pump it up to 20psi, if there is a leak pressure will start to drop, if so you will be able to track it down easier.
Keep pressure above 5psi, makes finding leak easier

Lower intake gasket replacement is just wrench work but takes time, you have to pull the valve covers, upper intake and disconnect fuel system.
This requires disconnecting most of the wiring on the upper engine, so take lots of pictures.

If it is lower intake gasket, I would guess 3 to 4 hours shop time, + gasket set + coolant, probably $400-$500, depending on where you live.

It is very easy to test Temp gauge system.
On the front of the lower intake just above Thermostat housing, you will see two temp readers screwed in to intake.
There is a TWO WIRE ECT sensor, that is only used by the computer.
There is a ONE WIRE temp Sender, this is used by the dash board gauge.

Unplug the 1 wire from the sender
Turn on the key, leave engine off
Temp gauge should be all the way down, COLD
Now take a short wire press it against contact of the 1 wire you unplugged and Ground the other end of the short wire.
Gauge should now show full HOT.

If this happens then replace the sender, wire and gauge are fine.
Do NOT use sealing tape on any 1 wire sender, the lower threads need to be bare metal to have a good Ground, the engine(ground) is part of this circuit.

 

Hey Ron, thanks for the quick reply. The leak is not coming from the front or rear of the engine. It is right on the side and about 2/3rds of the way down the engines side. It looks as though the wires and lines around the engine are also covered in coolant and I have been doing some more research and I am pretty sure it is not the lower intake gasket. Most everyone else says I would have more issues than just a small leak if it was the lower intake or even a head gasket. I believe I am looking for a cracked or loose line. Perhaps a freeze plug? I am going to look into it this weekend when I get some time to look and feel around. The leak has not gotten any worse over the past several days (150+ miles).
Any input or tips are appreciated,
Nick

 

Problem with small leaks is that they don't leak much or at all when there is no pressure in the system.
So you either use a pressure pump or warm up the engine to get some pressure in it.

There is a UV(ultra violet) die you can add to the coolant, run engine until warmed up, then shut it down and use an UV light to trace leak back to its origin.

I have had pinhole leaks in hoses that sent a stream onto another part of the engine, pain the the butt to track those down

 

Sorry I havent been on here in a week. I found the leak, it is just a freeze plug that is leaking out of the bottom. Weather here in Ohio has been horribly cold lately (down to -20 before windchill at my house one night). I think what happened is the gasket sealant that most people put around these freeze plugs to seal everything up broke down or came loose.
As soon as the weather warms up I am going to replace and reseal that freeze plug as well as a system flush and new coolant.
Thanks for the help,
Nick

 

Glad you found the leak.

If plug is hard to get to and replace with regular "pound it in" plug, you can use the rubber expansion plugs, they cost a bit more which is why Manufacturers don't use them, but much easier to install in most locations.

"Freeze plugs" are the popular term for these, but not accurate.
The holes are "core" holes, they are needed to remove the sand after an engine block has been cast with molten metal, a sand mold is used.
The metal pound in plugs are cheap so manufacturers use those.
And they have been used since the first engines were cast, so late 1800's.

Using strait water in the cooling system was all there was, and if the water froze some of the plugs would be pushed out, so I guess that is when people started calling these "freeze plugs" instead of core plugs.
Engine blocks also had drain plugs in the early years, hard to find engines with those now a days.
But the fact the plugs were pushed out would rarely save an engine from being cracked by freezing water, they don't allow water to drain out because the water is frozen, lol.

In any case just pointing out that the rubber expansion plugs do not endanger your engine in any way.

 

So the leak ended up not coming from the freeze plug. I found that the leak is running down both sides of the engine. I have looked at the lower intake gasket and it actually looks as though one of the previous owners has replaced it. It has a rubber outside and seems to be in pretty good shape. This past Thursday I looked at the whole engine compartment up towards the front for about 30 minutes. I think I found the actual leak, but I am not sure. It looks like it is coming from the thermostat housing.

Would this explain why it is dripping down both sides? It seems as though the leak is originating from the top of the engine and I can see antifreeze all around and under the housing when I turn off the truck. I am still only loosing maybe 1/8 to 1/4 cup of antifreeze per day. Anyway, I ordered a new thermostat today so I'll try that next. Are there any gaskets or seals I need to get for this? I have the 4.0L OHV V6.

I want to do all of the small stuff first before I start tearing in to look for possibly a bigger issue. Ohio has not been very warm this month, so I am trying to put everything off until it warms up (into the 40's at least). Still no antifreeze in my oil or exhaust so that is definitely a good sign.
Thank you,
Nick

 

Thanks for the posts on V6~4.0L~SOHC engines & TStat housings; good reference info.
Replaced the old leaking FRPlastic TStat Housing with a new Aluminum TStat Housing
in 2019Aug on a 2001 Ford ExSportTrac; no leaks as of 2020Mar after ~5K more miles.
My full write up with pics on that repair:
http://2001fordexplorersporttrac.fandom.com/Coolant_ThermoStat_Housing