2003 Explorer 4.6L Coolant Loss

[smerkal]

I know there have been a couple of threads on the subject but wanted to add my experiences so far with this issue. I have 20+ years exp wrenching everything from cars to aircraft to combines, but this is my first foray into the 4.6L.

I started losing coolant a while ago, slowly at first then increasing to about a gallon over 4-5k miles. Cooling system held pressure losing only 2 PSI overnight, cylinder leak down test showed loss past the rings but nothing into the coolant, compression tests OK, no obvious coolant when draining the oil, no external evidence of leak, but it continues to go away. The engine has 132,000 miles on it.

I decided to do some exploration to see what I could find. I pulled the intake and found a small crack in the plastic where the aluminum crossover tube attaches. Notice the line parallel to the end of my thumb.

Here it is with a light under it, you can see it goes all the way through.

And evidence of liquid in the valley

Thinking I had found my culprit, I decided to go ahead and reseal a leaking valve cover and replace the timing chains, etc due to a rattle at start up. When I pulled the valve covers I found this.

This seems like an excessive amount of goo to attribute solely to condensation, unless the crankcase vent on this engine is really that bad. Now I am not convinced the intake was my sole problem. I pondering if I should pull the heads anyway or go the extra mile and pull the engine to inspect bearings, etc. Anyone else been down this road recently? I recently replaced the differential due to howling and clutch chatter with a reman unit from Zumbrota Bearing and Gear (Great outfit) and rebuilt the tranny after the overdrive planet exploded, so I really am not ready to ditch this vehicle yet.....

UPDATE: After pressurizing and letting set overnight again, coolant drained out of the oil pan. The engine is now out on the stand for inspection and repair.

 

[rblais]

I had the same symptons as you have ( I didn't remove valve covers but had white crap in oil cap and the fill tube) with the crack in the intake manifold by the thermostat housing. I tried to seal the crack in the manifold with silicon gasket material but that repair lasted only a few miles before it bagan leaking again and fouling plugs, especially the #7. Coolant would drain along the rail and into the spark plug well. I replaced the manifold with a new one from the dealer and all is well for the last 10K+/- miles. I searched for aftermarket manifolds but none fit the 2005 4.6L Mountaineer though they looked very similar to the original. Good luck with the repair!

 

[smerkal]

I pulled it out and looked it over, it wasn't that much more work to get it out on a stand and it's much easier to work on than over the fenders

Definitely a head gasket leaking. I inspected two rod bearings and both looked like new. Apparently the newer aluminum bearings hold up to coolant invasion much better than the older babbitt style.

Heads are off to the machine shop tomorrow for cleaning, inspection, resurface, etc. Also found the right timing chain tensioner was worn clear through at the top and there were chunks of nylon and aluminum in the pan and oil pickup screen.

 

[esclamada]

Do you think that manifold leak could have contributed to the head gasket failure?
or might be the other way around?



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[smerkal]

No, the two are coincidental but exclusive. The manifold was leaking externally, but not enough to be evident. It was evaporating as fast as it came out. The intake can't leak into the crankcase on this engine. The two aren't connected (well, other than the vent system I suppose, but not very likely that coolant would go into the crankcase via the PCV system, but rather get pulled into the combustion chamber). It can leak externally or into the intake runner. The Head gasket failure is somewhat common on these.

I have the heads at the machine shop. We'll see what I end up with. After pricing the intake, I could get a used motor from the U Pull It yard for 1/3 the cost of the intake, but who knows what other problems I'd be buying. I'll definitely have to go there for the intake though......

 

[scottfab]

Where did this end up? No more leaks and no more gunk on the valve covers?
And is that still true. Especially the fluid loss?
How many miles since the work? or did you sell it?

I have been fighting this for a while now.
I think the two are related in that any slow leak leaves you vulnerable to low coolant. The design is such that the temp gauge is of no help until you get an engine warning light then you have 30sec to pull over before the engine shuts down. From there you have some head gasket work. The gauge simply does not show a rise until the warning light then pegs itself full CW.
The other way to "get to" replace the head gasket is by not burping the air out of the system effectively.

These slow leaks are very hard to isolate and since there is no "low coolant" sensor you have to constantly inspect the reservoir.

 

[smerkal]

Thanks for the inquiry. Got caught up in other things and neglected this thread.

I took the engine out of the vehicle and pulled the top end off. I also inspected the bottom end (bearings etc) due to coolant intrusion but it looked very good. Apparently the newer aluminum bearings and/or modern oils deal with coolant better then before.

The machine shop cleaned all the crap out of the heads and replaced the valve seals. Valve seats and faces looked good. I cleaned the block surface up carefully and reinstalled the heads with new MLS gaskets and bolts. I also replaced the timing chains, guides, etc. Its been rattling at start for a while and the right side tensioner/guide was worn clear through.

The intake was cracked but I had a hard time finding a used one. I ended up fixing the original by filling the o ring grove where the aluminum crossover attached with loctite plastic epoxy, filing smooth and attaching the aluminum piece with Right Stuff sealer.

After putting it all back together, it runs better and quieter than before, but still lost coolant very slightly. I ended up adding Bars Leak Head Gasket sealer to it (MLS gaskets are a bit picky) and it stopped. Apparently Ford adds a stop leak from the factory to newer mod motors.

I never had a temp issue, just noticed coolant loss during routine maintenance, then when my wife noticed heater problems (low coolant) I tore into it.

In the end, it's going strong and I got all the sludge out of it. Hopefully it's got a few years left.

 

[scottfab]

I never had a temp issue, just noticed coolant loss during routine maintenance, then when my wife noticed heater problems (low coolant) I tore into it.

In the end, it's going strong and I got all the sludge out of it. Hopefully it's got a few years left.

Actually I think my temp issue may have been related to using sealant as you did to eliminate the final slow loss of fluid. It caused the thermostat to stick partially open. When I tested it in hot water it stuck the first time then I forced it open and it would open and close in hot/cold water. I tossed it and got a new one anyway.

Overall it is amazing the similarities we've had. I have learned not to floor the accelerator. It some how makes the slow leak come back. Maybe it ups the pressure enough to plow out the sealant? Not sure.

Do you know if your rig set any codes? P03xx type codes?
FYI we not only share the same year and model Explorer but
I lived in Lincoln and went to UN there in the 70s.

 

[smerkal]

Depending on the type of stop leak used, it may or may not have been related. Hard to say.

No codes at all. The only time its ever had one is when the overdrive planetary shelled out, and that was pretty obvious why Its had a hesitation under heavy acceleration for a long time, and still does, like it doesn't want to downshift, but no codes. Its done this for a couple years.

Time will tell how mine holds out, especially once I resume towing my camper again this spring. Its paid for, has a new transmission and differential, and is still in overall good shape so I keep driving it. Worst case I toss a reman motor in it someday. Still cheaper than a replacement vehicle since I can do it myself.

I was in kindergarten in 79, but I spend everyday on the UNL campus at Nebraska Hall as a network engineer now.

 

[scottfab]

If the pictures below are missing, none of the below makes any sense now. The associate pictures sometimes don't show up so all you see are the titles to a well documented set of failures on the intake manifold.
I may come back later to diagnose what happening.
*************************************
Sorry about the pic resolution. I should have re-sized them to something reasonable.

Found similar issue to yours. This bulge in the intake manifold.

When I removed the bulging plastic piece I found this. It is packed with the block sealer I used earlier.
[

I filled in the void with flexible Permatex and lined the inside where the rubber O-ring like gasket with it too. (no pic posted but I have one.
Then I created this flat rubber gaskets to go between the metal connecting tube and the plastic intake part.

This is what the metal connecting tube looks like with both rubber gaskets.

I have replaced the head gasket and reassembled. No more code (yet) but I need to take it on the highway to be sure.

 

[scottfab]

Update

So far so good on my repair.
Looking back at this there is no doubt in my mind that the whole intake manifold design leaves much to be desired.
If you look at the fastening points at the front of the manifold on the passenger side you can see there is only one bolt holding the metal water runner in place. The other only other fastener is on the other side
of the air intake for cyl #1. This leaves a flimsy section of plastic as the only holding force. Combine this withe the alternator bracket bolted to the top of that water runner and you have it.
The alternator vibration coupled with the flimsy bracket and the heat of the engine on that plastic all combine to make for a weak spot right where the metal runner meats the plastic that is pinched between the water runner and the engine.
Best solution and one I'll pursue when this starts leaking again is to order the Edelbrock replacement design. Part # E1128385 for $330.
Also I will mention the cost of not monitoring the coolant level closely is the loss of a head gasket (or both). Don't ask how I know.
These allumninum engines are not at all forgiving on lack of coolant.
Head gaskets go very easily.

 

[esclamada]

I have been also trying to figure out the source of my slow coolant leak in my 2002 mercury mountaineer 4.6 V8. Finally today the culprit showed up, coolant showed up just below the thermostat housing. I put in ford stop leak last year but I think the gasket material (or the intake manifold) is so busted that the stop leak can't help anymore. Anyway I was wondering if I would just replace the gasket or replace it with Dorman Intake manifold. I contacted a guy who happens to have this intake manifold for $120 (new in box) but kind of hesitant to buy it because a gasket replacement might be enough to fix it. Is the current intake manifold worth replacing anyway with "Dorman Intake manifold kit" or just replacing the intake manifold gasket would do the job?

here's the pic; http://www.facebook.com/photo.php?f...39010486.10799.110528882348605&type=1&theater




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[smerkal]

You'll have to take it apart and look, but chances are the plastic is cracked and a gasket wont be enough since the underlying part is damaged. My repair with ABS epoxy and Right Stuff is holding up thus far. My original issue was actually a head gasket though and this was discovered in the process of repairing that. If you can't/don't feel up to making a repair then the only choice is replacement. Take it apart and look first, but it's likely more than just a gasket issue.

 

[esclamada]

I have been also trying to figure out the source of my slow coolant leak in my 2002 mercury mountaineer 4.6 V8. Finally today the culprit showed up, coolant showed up just below the thermostat housing. I put in ford stop leak last year but I think the gasket material (or the intake manifold) is so busted that the stop leak can't help anymore. Anyway I was wondering if I would just replace the gasket or replace it with Dorman Intake manifold. I contacted a guy who happens to have this intake manifold for $120 (new in box) but kind of hesitant to buy it because a gasket replacement might be enough to fix it. Is the current intake manifold worth replacing anyway with "Dorman Intake manifold kit" or just replacing the intake manifold gasket would do the job?

here's the pic; http://www.facebook.com/photo.php?f...39010486.10799.110528882348605&type=1&theater

I just did the fix this weekend, it was worst inside the manifold. The gasket is intact but there were some rubber gasket inside the manifold that wrinkled out and the rear hole has a crack inside. It's really time for a new one.

Truck is running good without coolant leaks.

http://www.facebook.com/media/set/?set=a.360434580691366.78120.110528882348605&type=3


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[scottfab]

I think you typed inside the QUOTE tags. If you do that your comments are buried inside with what was posted before.

I too have a bad manifold. Been patching it over and over. Tired of it.
Let us know which one you order and how it works. I wan to get an all aluminum one. I've had it with plastic.

 

[esclamada]

I used the Dorman Intake manifold, it is still plastic with aluminum crossover, same construction as the original (without the foam enclosure or valley stuffer)

On amazon it's $155 and has good reviews. In my opinion this is really a good replacement than the original. Time will tell how long this manifold will last.

http://www.amazon.com/Dorman-615-17...002&vehicleType=automotive&newCar=1&carId=002

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[scottfab]

I have found two to chose from that are apparently alluminum:
1. This one is $299
http://www.summitracing.com/parts/EDL-28385/

2. This one has no image but says "satin" finish implying aluminum. I need to call them to confirm but it is $134
http://www.discountairintake.com/store/?N=0&Nr=AND%28OR%28category%3AAir+Intake%2Ccategory%3AFuel+Delivery%29%2Cyear%3A2003%2Cmake%3AFord%2Cmodel%3AExplorer%2Csubmodel%3AEddie+Bauer%2Cengine%3A8+Cyl+4.6L%2Cuniversal%3A0%29&PN=0+3843&VN=4294963878+4294963620+4294967118+4294963811+4294966440&Nr=AND%28OR%28category:Air%20Intake,category:Fuel%20Delivery%29,year:2003,make:Ford,model:Explorer,submodel:Eddie%20Bauer,engine:8%20Cyl%204.6L,universal:0%29

 

[esclamada]

my concern on those 2 is that they might require new throttle body and set of injectors. I have a 98 continental (4.6L V8) and the manifold is all aluminum (looks exactly the same as my 02 Mercury) Not sure if they fit perfectly though (the height is an issue among these manifolds on 4.6L V8 engines)




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[tower]

I have found two to chose from that are apparently alluminum:
1. This one is $299
http://www.summitracing.com/parts/EDL-28385/

2. This one has no image but says "satin" finish implying aluminum. I need to call them to confirm but it is $134
http://www.discountairintake.com/store/?N=0&Nr=AND%28OR%28category%3AAir+Intake%2Ccategory%3AFuel+Delivery%29%2Cyear%3A2003%2Cmake%3AFord%2Cmodel%3AExplorer%2Csubmodel%3AEddie+Bauer%2Cengine%3A8+Cyl+4.6L%2Cuniversal%3A0%29&PN=0+3843&VN=4294963878+4294963620+4294967118+4294963811+4294966440&Nr=AND%28OR%28category:Air%20Intake,category:Fuel%20Delivery%29,year:2003,make:Ford,model:Explorer,submodel:Eddie%20Bauer,engine:8%20Cyl%204.6L,universal:0%29

The second one says it's a upper plenum, I would love to know if anyone has tried that Edelbrock one looks nice.

 

[scottfab]

The second one says it's a upper plenum, .

Yah I have no idea what that mean but will be calling them.