Coolant Leak...With pictures!

[Brickthing]

So it is a 4.0l 2003. Leak is about 1 drop every second while running and coming from the passenger side. I got the Pittsburgh pressure leak tester and it worked about as good as anything else from my boys over at Harbor Freight which is to say the cap wouldn't fit because of a defect. Knowing my luck it is coming from the water pump, but I figured I'd let the experts here toss some ideas. It is not the radiator and does not seem to be any of the hosing associated with the radiator. Appreciate any insights! This would be the second Ranger where I had to replace the water pump because of a leak

Unrelated, but looking for the coolant leak I found my vacuum leak instead! HA! Guess who's gonna be sitting with AC actually blowing on me now

 

[Brickthing]

For anyone curious, after searching this forum and the google machine my bet is the thermostat housing as I can see potentially a very small amount of coolant around the seems of it. When I get the replacement pressure tester I will know for sure, but I feel mediocrely confident that is probably the issue.

I'm thinking of getting this part, but allegedly it doesn't fit a 2003. It looks the same though? https://www.1aauto.com/*/i/1AEMX00432

 

[sgtsandman]

I'm having difficulty determining where the photos are showing the leak in the picture. At the back of the engine by the transmission?

In anycase, the plastic thermostat housing does have a tendency to leak over time as the plstic gets old and brittle. A few of us swapped that out for an aluminum one made for the Ford Explorer. Being that the t-housing sits right at the front of the valley of the engine, I suppose it could leak into the valley and eventually run back.

Before you spend the money, see if you can clean any dirt and grime off the engine so you can better see where any leaks maybe originating from. The passenger side is more difficult because of the evaporator housing. A mirror may help or looking at the engine through the wheel well instead of underneath or over top.

 

[Brickthing]

For anyone who is wondering I got another coolant leak tester and it was the thermostat housing by a land slide. It leaks like crazy when put under pressure.
I'm replacing it with this aluminum one: https://www.amazon.com/dp/B0BZH8Z9DV?psc=1&smid=ATVPDKIKX0DER&ref_=chk_typ_imgToDp

 

[mperry]

I have a '94 4.0L and finally located my leak. I'd rented O'Reily's pressure tester but it was useless on the Ford. (The plunger was 1/8" too short to make a seal.)

It's a learning experience, as in the transmission is water cooled. There's a fitting at the top and bottom of the plastic tank (driver's side) and the upper fitting has lost its seal. Unfortunately they don't make radiators that can be worked on, so it'll require a new radiator for this minor repair. It sucks that a $1 gasket is going to cost me hundreds and throw away a radiator otherwise in perfect condition.

It's one of those sneaky leaks. There wasn't a drop of antifreeze on the ground but I lost nearly a gallon of antifreeze. I only noticed because I needed to refill the washer fluid and noticed the overflow was empty.

 

[pentode]

I have a '94 4.0L and finally located my leak. I'd rented O'Reily's pressure tester but it was useless on the Ford. (The plunger was 1/8" too short to make a seal.)

It's a learning experience, as in the transmission is water cooled. There's a fitting at the top and bottom of the plastic tank (driver's side) and the upper fitting has lost its seal. Unfortunately they don't make radiators that can be worked on, so it'll require a new radiator for this minor repair. It sucks that a $1 gasket is going to cost me hundreds and throw away a radiator otherwise in perfect condition.

It's one of those sneaky leaks. There wasn't a drop of antifreeze on the ground but I lost nearly a gallon of antifreeze. I only noticed because I needed to refill the washer fluid and noticed the overflow was empty.

Forgive me, I’m slightly confused about your problem. To my knowledge there are no water cooled transmissions. Do you have a coolant leak or a trans fluid leak? They’re separate systems. Don’t replace your radiator without more data.

Edit: I can’t find the original thread if there is one. Please start one before you replace your radiator.

 

[sgtsandman]

Forgive me, I’m slightly confused about your problem. To my knowledge there are no water cooled transmissions. Do you have a coolant leak or a trans fluid leak? They’re separate systems. Don’t replace your radiator without more data.

Edit: I can’t find the original thread if there is one. Please start one before you replace your radiator.

I believe the person you are replying to is talking about the transmission cooler built into the bottom of the radiator. I have heard of those springing a leak. Usually with horrible repercussions for the transmission since the coolant contaminates the ATF.

 

[sgtsandman]

I have a '94 4.0L and finally located my leak. I'd rented O'Reily's pressure tester but it was useless on the Ford. (The plunger was 1/8" too short to make a seal.)

It's a learning experience, as in the transmission is water cooled. There's a fitting at the top and bottom of the plastic tank (driver's side) and the upper fitting has lost its seal. Unfortunately they don't make radiators that can be worked on, so it'll require a new radiator for this minor repair. It sucks that a $1 gasket is going to cost me hundreds and throw away a radiator otherwise in perfect condition.

It's one of those sneaky leaks. There wasn't a drop of antifreeze on the ground but I lost nearly a gallon of antifreeze. I only noticed because I needed to refill the washer fluid and noticed the overflow was empty.

Check your transmission fluid and make sure the coolant hasn't contaminated the transmission. If it has, I would highly recommend not driving it until you get the radiator replaced and replace the transmission fluid. It's going to take about three drain and fills to get the majority of the old ATF out, with some driving in between each drain and fill. Hopefully you caught this soon enough that it hasn't damaged the transmission. Assuming the cooler is leaking into the transmission and not directly out of the bottom of the radiator.

 

[sgtsandman]

For anyone who is wondering I got another coolant leak tester and it was the thermostat housing by a land slide. It leaks like crazy when put under pressure.
I'm replacing it with this aluminum one: https://www.amazon.com/dp/B0BZH8Z9DV?psc=1&smid=ATVPDKIKX0DER&ref_=chk_typ_imgToDp

Check to see if you have two sensors or only one. If only one, try to find the aluminum housing with only one port since the dual port ones don't always come with the plug to seal the unneeded port.

 

[Brickthing]

Check to see if you have two sensors or only one. If only one, try to find the aluminum housing with only one port since the dual port ones don't always come with the plug to seal the unneeded port.

Yeah I noticed that some have two and others one. I have the two version. From what I read though I am going to have to buy another sensor since I guess people were saying that the brown one doesn't work with the rangers. I am honestly not sure about that part.

 

[sgtsandman]

Yeah I noticed that some have two and others one. I have the two version. From what I read though I am going to have to buy another sensor since I guess people were saying that the brown one doesn't work with the rangers. I am honestly not sure about that part.

I think I used my existing sensors since there was nothing wrong with it but I don't remember for sure.

 

[Brickthing]

I think I used my existing sensors since there was nothing wrong with it but I don't remember for sure.

I figure I can just plug it in and see if it pegs high or not. If it doesn't cool. If it does just do the swap like you did.

 

[Brickthing]

Check your transmission fluid and make sure the coolant hasn't contaminated the transmission. If it has, I would highly recommend not driving it until you get the radiator replaced and replace the transmission fluid. It's going to take about three drain and fills to get the majority of the old ATF out, with some driving in between each drain and fill. Hopefully you caught this soon enough that it hasn't damaged the transmission. Assuming the cooler is leaking into the transmission and not directly out of the bottom of the radiator.

Yeah this seems like a new transmission to me. What do I know though. Just imagining all my coolant mixing with ATF gives me goosebumps.

 

[Brickthing]

For anyone who happens to come by this post in the future here is a picture of the finished product. Here are some notes. The sensors that came with the part from Amazon worked fine. I have a Ranger 2003 4.0L engine so do with that what you will. To take off the very back bolt towards the cab you can just push the electrical wires towards the radiator and use a socket on it in order to get it off. None of my bolts were seized, but that is a common issue.
My lower hose leaks a little at 7 psi so if you can you may want to replace that one since it is short and with the temp hosing off will be a easy replace. I just slapped another hose clamp on it and called it a day, and to be entirely honest I am not entirely sure what the system normally runs at while operating so it may be a non issue. Good luck!

 

[Broosedamoose]

When I replaced mine with the aluminum housing it didn't come with any sensors so I just used my existing sensors. I second the idea of replacing the small hose. Mine wasn't leaking but it was a bit brittle so I just threw a new one on to save me the hassle down the road.