Still losing coolant...HELP

[wesalexleft]

I've been losing coolant from the reservoir on a 2003 Mountaineer with the 4.6 V8 at a rate of about 1/4" per day at 15-20 miles of driving. I found a small leak on one intake manifold gasket, so this weekend I replaced the intake manifold, gaskets, thermostat, etc. I've been over the entire engine compartment and can't find any signs of coolant leaking. I completed the repair on Sunday and as of this Tuesday AM, I've gone from the top "cold fill" line to the bottom "cold fill" line. I burped the system at fill up. I'm sure there could have been some air still in the system, but I think I may still be losing coolant from somewhere. There are no signs of coolant on ground or engine compartment. I've felt around the carpet and nothing there, nor any fogging problem with the heat on. HELP...where else should I look for a leak?

 

[Flag Gibby]

Pull the dipstick and make sure that there is no coolant in your oil. I don't think that there would be, but just check to make sure. How much coolant have you put in the system since you replaced everything, I don't know the capacity of the V8, but that would give you an idea how much over capacity you have added at this point.

 

[wesalexleft]

Oil looks good. No sludge in the filler cap and the dipstick looks clean. I'm not sure of a total amount of fluid added. When I replaced the manifold, I drained the system, but nowhere near the total fluid capacity, so all I could do was "top it off". I haven't had any noticable smell of hot coolant either. This leak has me stumped. If it were mine, I'd just keep an eye on it, but it's my son's and I can't depend on his remembering to watch the level, and with him "off to college" I don't want him running it hot. It's at my house for about another month before he takes it back with him, so I'm trying to get it resolved before then.

 

[MrBean]

u can pressurize the cooling system with this loan coolant pressure tester from Autozone:

http://www.autozone.com/autozone/inourstores/lat/latLanding.jsp?bodyContent=heatingAndCooling

i normally pressure it up to 10psi, check the cap first....hope this will help...looking for this kinda mystery leak is not easy..good luck

 

[pet575]

I'd start with the cap. Cheap and easy after you've done all the other stuff.

 

[jimandnena]

Oil looks good. No sludge in the filler cap and the dipstick looks clean. I'm not sure of a total amount of fluid added. When I replaced the manifold, I drained the system, but nowhere near the total fluid capacity, so all I could do was "top it off". I haven't had any noticable smell of hot coolant either. This leak has me stumped. If it were mine, I'd just keep an eye on it, but it's my son's and I can't depend on his remembering to watch the level, and with him "off to college" I don't want him running it hot. It's at my house for about another month before he takes it back with him, so I'm trying to get it resolved before then.

This is a long shot but check the trans fluid as well. I had a crack in the trans cooler in the radiator that would seep coolant into the trans. When I finally found it, the trans needed a total rebuild.
jim

 

[wesalexleft]

I've driven the truck for the week and I'm still losing coolant at a rate of about 1/4" per day. I have a question for the climate experts. Seems it only loses coolant while running. I'd pressure tested the system and no leaking was observed or drop in level. Does the heater coolant valve close off that coolant circuit when there is no vacuum applied? If so, that would indicate a leak after the valve. I'm going to trace those lines this weekend. Can the rear heater core be inspected or serviced without emptying the freon? The rear fan is out, so I haven't had any fogging problems with the heat on. I would think I would have fogging if it were the front heater core. I have a scope of there's a way to do a visual on the rear core without releasing r-22.

Thanks

 

[tower]

Your truck has no r-22 in it, it has r-134a you can get it at any walmart. If you think it's the rear core and from your post it seems you are not using it why not just block the lines off under the hood. You could also disconnect the lines and pressure test them from under the hood.

 

[wesalexleft]

Heater core lines

Sorry, meant 134-a. Are there separate lines for the front and back heater cores? I'm aware of the lines on the passenger side firewall and assumed they handled both cores. I suppose I could "loop" the lines under the truck going to the back core as a test if that can be done. I've seen pics in the Haynes manual, but have not gone under the back of the truck yet-will this weekend. Crossing my fingers it's a line and nor the cores themselves. Replacing the front makes the intake manifold look easy.

 

[Exproblems]

I have a scope of there's a way to do a visual on the rear core without releasing r-22.

Thanks

Like Tower said, your Ex doesn't use R-22. FYI, R-22 is what is used in home window AC units. Older style automotive refrigerant was R-12, which has been replaced by todays R-134A.

 

[JCR]

Replace the pressure cap on the overflow bottle and I will be willing to bet your problem will go away.

 

[tower]

Sorry, meant 134-a. Are there separate lines for the front and back heater cores? I'm aware of the lines on the passenger side firewall and assumed they handled both cores. I suppose I could "loop" the lines under the truck going to the back core as a test if that can be done. I've seen pics in the Haynes manual, but have not gone under the back of the truck yet-will this weekend. Crossing my fingers it's a line and nor the cores themselves. Replacing the front makes the intake manifold look easy.

Yes there are separate lines you can block off under the hood, you can also get the lines in the back under the truck but that is much harder.

Under the hood pass side follow the line from the firewall to the front of the motor, you will find a vacuum valve and a T fitting. From the T fitting you will see one of the lines off of it joins up with 3 other lines and heads under the truck towards the back of the truck. 2 of them are for heat and 2 are a/c for the rear heat and a/c.

I will take a pic and post if needed.

 

[esclamada]

Try putting in some coolant dye first. Test if for several days or take it for a long drive. The dye will stain even with the heat.



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[wesalexleft]

Thanks for the tips. Coolant dye has neen ordered and should be in soon. I'll look to isolate the cores to see what that does next. I've already replaced the cap, but no luck there. new intake and gaskets too. I had corrosion on the intake gaskets, so I replaced, but it wasn't the problem. Anybody else who's had tricky leaks they've found so I have other places to check?

 

[wesalexleft]

Dye shows nothing, rear heater core service?

I've run dye through the coolant and see nothing in the engine bay. No wet carpet up front. I pulled the cup holder off the driver side rear quarter trim and think I smell coolant inside the panel. Is there a way to visually inspect the rear core without completely dismantling the unit and losing the a/c charge??? Has anyone done a rear heater core replacement???

Thanks,

 

[tmaher]

you could have a bad head gasket. a small leak into a cylinder during combustion will not necessarily be seen out the tail pipe.