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Coolant woes

wesalexleft

Well-Known Member
Joined
August 2, 2009
Messages
148
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City, State
Memphis, TN
Year, Model & Trim Level
2003 Mountaineer V8 4.6L
Coolant woes**leak found, need advice**

2003 4.6L mountaineer. This is my son's daily driver to and from college. It sits for a while at a time followed by the 6 hour road trip home and back on occasion. Last trip home, it ran hot. He pulled over, called and asked for advice. He let it cool down, added water, and finished the drive home. It's been sitting for quite a while with the occasional city drive while he's been home. I drove it the first cool day, and there was no internal heat. Dreading the blend door issue, I looked into it, butto found the coolant again low again. I've topped it off and begun tracing down the problem, but so far no luck. Making the blend door seem like a blessing, the 4.6L head gasket fears took over. I've looked, but no signs of coolant leaking anywhere. I've checked the thermo, hoses, carpet, and intake as best I could with limited view and no leaks. I've done a block leak test and no hydrocarbon found in the coolant. Pressure tested the coolant system and I don't believe it's losing serious pressure. I pumped it up to 20lbs cold, and it did drop to 15lbs over 30 minutes, and then stabilized there for the next 2 hours. Not sure if this is a sign of problems, but I depressurized, left the pressure guage on the resivoir, started the engine, and at operating temp, the guage read about 4-5 pounds pressure. IDK what normal pressure should be. I'm waiting on an oil analysis kit, but the dipstick looks and feels like normal oil. Oil fill cap looks good as does the filler neck. There is some very dark oil sludge, but no milky white residue. I tried pressure testing the coolant cap, but either the cap is bad, or the adapter didn't get a good seal, so I'll be picking up a cap tomorrow. I also have a inspection scope ordered to try and look beneath the intake manifold for possible signs of a leak that may be boiling away without being seen. Any other possibilities? It's running normally, minus a possibly bad IAC. one other worth mentioning, the intake manifold is original, but does have the aluminum crossover for coolant. The truck was bought end of '03 and I believe has an improved intake manifold. The only things nor done are visibles of heater cores, but no wet carpets.

Thanks!
 



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Anyone had problems with the reservoir cap causing lost coolant with no signs of water around the bottle, or any other things to watch for as i wait on the used oil analysis kit? Sorry for the earlier typos...it was late, no glasses and working from a tablet with no keyboard. I haven't found a source for the missing coolant and I'm running out of places to look. Coming up is a compression check if all else fails, but seems like the block test or dipstick/filler cap would have shown up signs if it was head gasket or heads. Intake manifold...not so sure. I haven't seen any white smoke. I took it on the interstate and both cruised as well as some downshift acceleration and saw none in the mirror. As soon as the inspection camera comes in, I'll be able to have a better look there.

Any tips/suggestions/experience is appreciated.
 






missing coolant

I haven't found a source for the missing coolant and I'm running out of places to look. Coming up is a compression check if all else fails tips/suggestions/experience is appreciated.

Have you looked at the thermostat housing?

I had the same problem, missing coolant but nothing on the floor or on the engine. Mine is 4.0 liter so not sure what difference in t-stat housing.

Mine leaked at the rear of the t-stat housing and it was never wet because it starts to leak when it gets hot and pressure builds but when the water leaks out the back of the housing it hits the maifold and vapoizes so no liquid to be seen.

I had it pressure checked at the radiator shop and it was evident where the leak was under pressure. The engine was hot at the time as well.

If you want you can feel around the housing at the back side and it will be wet and HOT so be careful.

I'm betting that's going to be the source and it's a pretty easy fix. :D
 






I've called myself checking it over, but I'm baffled and will check it again to be sure. I looked and didn't see any signs of coolant, corrosion, chalk, or staining. Mine is aluminum from the crossover tube, and has a black plastic undside cover and an aluminum top cover. I've had a mirror out and looked all around, but the back (against the intake) was VERY difficult to inspect. I did let the truck cool down, and put 20LBS of pressure on it to look for leaks that might be evaporating otherwise, but still no wetness that i could see.
 






Any other places to look???

I'm still looking to trace down this small leak. It being my son's college car, I'd like to know its good before he takes it out of town again next semester. I've checked the thermostat really well, nada. New cap on reservoir. No visible coolant anywhere. I've taken an inspection camera to every major hose, radiator, and still nothing. I've driven it the past three days (45 miles) and the coolant has dropped approx 3/8" inch in the coolant reservoir. I've done the block test with no carbons in the coolant. I have ordered a oil analysis kit, but still waiting on the kit and expect it to be several weeks before I get results from that. Just asking for anyone who has had a leak, so that I can look where others have had leaks appear. No wet carpets in front. There are rear climate controls-is there a rear heater core, and if so, I have no sign of wet carpet in rear driver side cargo. Absolutely no coolant hitting the ground even after sitting on a pump for an hour at 20 LBS.
 






Any chance there is just air in the system and when you are driving it is just bringing the air up, and the level down?
 






And your not blowing white smoke from the exhaust?
 






Nope, no white smoke. From what I'd understood, the block test would have showed hyrdocarbons in the coolant with the head gasket leak. Also, the coolant pressure when running is around 5 LBS. If it was a head gasket, wouldn't the pressure be very high as compresson was leaking into the coolant system?
 






Sorry, about air in the system...there definately was, and I managed to burp most out. I could hear a little in there while pumping the uppper rad hose, but its pretty much all gone now. Still, for all that air to get in there, fluid had to leave at some point, right? My last thought is that when it overheated on my son, it could have been stuck thermostat...then it boiled over, and that caused the low water, and subsequent air in system which I've been burping out. I guess if coolant stops leaking down soon, I'll just put a thermo in. I was hoping I'd get several responses to checke the XX hose just behind the XX...or something like that.

Thanks!
 












As of today, I believe I've found the leak. It's very small, but I was only losing approximately 1/8" to 1/4" per day from the reservoir. It took an inspection camera to get at the leak, and the video will be available later. It appears the intake manifold gasket is failing at the rear driver's side to the manifold just below and around the bolt securing it to the motor. There is corrosion around the mating surfaces and a very small water trail which is then disappearing at the motor/tranny area. It never touches the ground. I only found it with the motor stone cold and pressurized to 20lbs along with the mini inspection camera. Now to the question---this is a pain in the butt repair from what I've read. The truck is a late 2003---should I replace the manifold and gaskets, just the gaskets, or just tell my son he has GOT to top off the fluid at fill ups and let it go a while? I've seen some say the intake isn't that bad to replace, but things always go wrong, and I'd hate to have a fuel rail problem or similar make for a bad day and in-op truck that now just has a slow leak. Thanks to all!!
 






I don't think it's an improved manifold design, the improved one should be all aluminum. It's not that bad replacing the manifold, it's just taking a lot of time since you have to drain the coolant, remove the injectors, alternator and plugs. It's pretty much a complete tuneup after doing the replacement (clean throttle body, injectors, belt and replace plugs)

I replaced mine with a dorman intake manifold and it's still doing very well. Mine has the visible leak going through the transmission bell housing, I put in a ford approved stop leak and it helped for a short time until the leak is visible just under the thermostat housing. At this point I decided that I need to replace it when I saw a part for $100 in craigslist.

You're better off replacing the intake manifold while it's not leaking that bad. I have taken pictures on how bad they are internally and coolant flowing into the valley.



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Here is a link to a YouTube video of the inspection camera and the leak. Forgive the lack of audio or text commentary so far. I plan on adding some points of reference later. The leak is at the rearmost intake manifold bolt on the driver side beneath a bunch of wires.

http://www.youtube.com/watch?v=reLbq91O68s&sns=em

I would like to get some advice on what manifold, the Dorman or OEM, and the best source for an OEM. Fordpartsdirect is over 400.00. Anyone had problems with the Dorman unit?
 






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