Updated 11/13: Help! Replaced housing, but still have leak? | Ford Explorer Forums - Serious Explorations

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Updated 11/13: Help! Replaced housing, but still have leak?

texasbanzai

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Joined
February 9, 2010
Messages
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City, State
Arlington, TX
Year, Model & Trim Level
'02 Sport Trac
02 Sport Trac Coolant Leak

I need some advice on how to tackle a coolant leak in my '02 Sport Trac with about 145,000 miles. [Edit: Forgot to add, V6 4.0L SOHC]

I turned on my heat last week for the first time this year and noticed it started randomly blowing cool and I also noticed the temp guage fluctuating a little. When I checked the coolant was about 1-2 quarts low. I hadn't noticed any persistent coolant smell or leak stains where I park before this. After topping it off the smell has been pretty noticeable when the truck is first run but seems to subside after being run for awhile (I drive ~30 mi to work each way) and haven't seen any large puddling of water. It seems to be leaking about 1 cup or so per day or two.

I am going to replace the whole thermostat housing and associated parts this weekend since this seems to be a common cause of coolant leaks (and thanks to the post on these boards for the great how-to walkthrough!).

My concern is that I have not been able to get a good view of where the leak is actually coming from. I am positive there is a leak somewhere but because of the cramped conditions I haven't been able to see where the leak is coming from. There doesn't appear to be a leak from any of the coolant hoses on the upper side of the engine. I have been to find the coolant leak landing onto the engine block (see picture below, red area), but can't figure out where it's originating from.



I'm trying to figure out the best option for figuring this thing out. I am going to get a pressure tester from AZ tomorrow and am hoping to employ some coolant dye. I'm considering pulling the alternator and removing the fan to give myself more room to look around the coolant system to see if I can find the leak. I'm worried there may be a leak somewhere closer to the water pump or from the water pump itself.

In full disclosure, I'm not an experienced mechanic and have never done the majority of this work, so any advice is very much appreciated. Namely, I'd like to avoid having to disconnect the fan (this seems pretty daunting), but I can't seem to get much room to look around with a mirror with the belt and fan taking up so much space.

Thanks, Adam
 



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could be the waterpump, I replaced mine recently.

it's hard to see a waterpump leak, since the pulley hides it well. the bushing wears out and coolant leaks from the weep hole.

if I remember correctly:
- drain coolant
- unscrew fan shroud,
- remove fan (need to get fan off pump unless it's electric), and the shroud
- remove water hoses from pump
- remove waterpump
- clean mating surfaces (block)
- install new pump
(there maybe a step or 2 missing)

I couldn't verify 100% my pump was leaking, but decided to change it after constantly seeing some coolant on the ground and not finding a leak. after pulling off the fan and pulley it was pretty obvious the pump was leaky.
 






- unscrew fan shroud,
- remove fan (need to get fan off pump unless it's electric), and the shroud

Any idea how difficult it is to get the fan out? My Chilton book (which of course doesn't really cover the Sport Trac) says there may 2 or 4 fan shroud screws, or that it might just slip into a holder/clips.

Also, any idea how hard it is to disconnect the fan from the pulley? I can get a fan wrench to help but I wanted to double check and see if it was any more complicated than it looks.
 






for my truck shroud is 2 screws (bolts) up top, and bottom is clipped in

the fan will be an issue.
you will need special tools for that, possibly could rent them from a parts store. - holder for the pulley, and a very big slim wrench to undo the fan bolt from water pump. Can't remember if it's reverse thread on the truck now.
 






I put some tracer dye in the system and ran it around the block to get it warmed it. After taking a blacklight to it, it definitely looks like there is a leak around the thermostat housing (it's glowing bright all around each seam). Also, after finally getting under the truck I could see coolant all over the place. I'm hoping there won't be too much permanent damage after I get it all cleaned off.

Today was our first cool day and it was down over a quart today just from the drive to work and back. I'm thinking the cold weather is making the situation worse. I'm hoping that running a pressure test while to block is nice and chilly tomorrow morning will show me a definitive culprit.

I guess we'll see...
 






I picked up the pressure tester this morning and tested the system. There was no DOUBT that it was leaking from the thermostat housing. It was spewing everywhere at just 10 PSI!

I worked for hours trying to disconnect the old one and installing the new one. I installed every piece new except for the 6 bolts for the housing (the dealership said they would take awhile to get since they would have to be special ordered and weren't carried by anyone local). I double checked to be sure that the tabs weren't broken during install and that the gasket stayed seated. Refilled the system with about 1.5 gallons of coolant and I pressure tested the system and it held at > 15 PSI without any leaks for over 5 minutes. Reinstalled the throttle body and air intake.

I had my wife start the engine and coolant started POURING off the back of the engine block! We killed the engine and pressure tested again. No leak and it held pressure. We pulled it out of the garage to see if maybe it was just some left over coolant that had been sitting on the block. After she pulled back in to the driveway it started leaking heavily again! I've had it on the pressure tester for more than 15 minutes and it has held without any dripping. I can't figure this thing out!

ANY ideas or advice would be appreciated! I'm concerned that maybe the leak is somewhere "behind" the thermostat and that's why we can't see it with the enging off. But I don't know almost anything about cooling systems. It seems like the water pump wouldn't be able to generate pressure until the thermostat opened up anyways, so I'm not sure if would really explain why it leaks with the engine on.
 






I don't know what to say, this problem sounds weird.
did you fill and burp the system, there could be lots of air in there. check heater hoses, and hard lines (metal) around the back of the engine.
 






lower intake manifold gasket or freeze plug leak?
 






I can only guess that this was some kind of fluke. I was really terrified that I had blown a head gasket or that a freeze plug was leaking.

I took off the pressure tester and ran the engine until warmed and couldn't find any more leaking. Let it cool down and checked the level. It was about a cup or so low, so I topped it off again. Ran it to hot once again and still no leaks. Went to the car wash and rinsed the entire top of the engine off with water, especially around the housing. I also rinsed off the underside and ran through a car wash with an undercarriage wash. I haven't seen any more leaking and, for the first time in a week, no more coolant smell.

I can only guess that there was a good amount of coolant that had pooled up on top of the engine block from when we put the system under pressure. I guess that when the engine was turned on the fan blew a good amount of that out the back of the block, and when it drove back up the incline of the driveway whatever was left poured off. At least, I sure hope!

First, I would like to thank you for your help.

And I feel it would be a disservice to not mention how helpful the walkthrough for replacing the thermostat housing is. The job was not easy (it took myself and another 4+ hours to complete it), but it would have been MUCH more difficult without such a well thought out and organized set of steps.
 






I need some advice on how to tackle a coolant leak in my '02 Sport Trac with about 145,000 miles. [Edit: Forgot to add, V6 4.0L SOHC]

I turned on my heat last week for the first time this year and noticed it started randomly blowing cool and I also noticed the temp guage fluctuating a little. When I checked the coolant was about 1-2 quarts low. I hadn't noticed any persistent coolant smell or leak stains where I park before this. After topping it off the smell has been pretty noticeable when the truck is first run but seems to subside after being run for awhile (I drive ~30 mi to work each way) and haven't seen any large puddling of water. It seems to be leaking about 1 cup or so per day or two.

I am going to replace the whole thermostat housing and associated parts this weekend since this seems to be a common cause of coolant leaks (and thanks to the post on these boards for the great how-to walkthrough!).

My concern is that I have not been able to get a good view of where the leak is actually coming from. I am positive there is a leak somewhere but because of the cramped conditions I haven't been able to see where the leak is coming from. There doesn't appear to be a leak from any of the coolant hoses on the upper side of the engine. I have been to find the coolant leak landing onto the engine block (see picture below, red area), but can't figure out where it's originating from.



I'm trying to figure out the best option for figuring this thing out. I am going to get a pressure tester from AZ tomorrow and am hoping to employ some coolant dye. I'm considering pulling the alternator and removing the fan to give myself more room to look around the coolant system to see if I can find the leak. I'm worried there may be a leak somewhere closer to the water pump or from the water pump itself.

In full disclosure, I'm not an experienced mechanic and have never done the majority of this work, so any advice is very much appreciated. Namely, I'd like to avoid having to disconnect the fan (this seems pretty daunting), but I can't seem to get much room to look around with a mirror with the belt and fan taking up so much space.

Thanks, Adam

Your problem is not common to me. And I don't have any ideas on it. I think it's time for you to go in an expert mechanic. That's just my stupid suggestion to you. Sorry for that.
 






Your problem is not common to me. And I don't have any ideas on it. I think it's time for you to go in an expert mechanic. That's just my stupid suggestion to you. Sorry for that.

Uh, I think he fixed it.;)
 






Uh, I think he fixed it.;)

Or, at least, it isn't leaking that I can tell anymore. :)

No coolant smell and I haven't seemed to find any big coolant stains lately, so I'm thinking this fixed it.
 






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