Cobra lower intake question - coolant leak

[Stormwalker]

Alright, I'd like to get my car out pretty soon, but it needs a repair. I put in new temperature sensors last year, and immediately after I did that it started leaking coolant around the front of the intake, like around the distributor (small amount where the intake meets block) and it's collecting at the top of the timing cover or whatever. Not a horrible leak (was still driveable) but a leak nonetheless. A couple of people surmised that I overtightened the temperature sensor and might have slightly cracked the bottom of the lower intake or something. This is the only thing I think it could be, because I replaced the timing cover/water pump gaskets, and replaced the intake to head gaskets again just to be sure it wasn't a bad gasket (even though they had less than 1000mi on them), and the problem persists.

So, my question is, would this be repairable? Like if I take it to a machine shop or something? Otherwise, this is a Cobra intake, so I would imagine getting a used lower off of an Explorer would work as well. I have called around and apparently there are a couple of different codes for the Explorer, and I am not sure which one works. Car-part.com comes up with these different IDs:

F67E-BB
F87E-CA
XL2E-AB

Anyways, maybe the simplest thing would be to get the current lower repaired if that is even possible. I know another option would be to buy a whole new intake (like an Edelbrock) but I had my car dyno tuned with the stuff on it now, not sure if throwing a different kind of intake on my car would screw everything up now or not.

Any input would be appreciated!

 

[TomCat]

Well since you have to pull it off either way, just do that and check the extent of the damage. It is possible to weld and such on the aluminum, so if it's only like a hairline fracture, I figure a shop would be able to weld it up or whatever... and if it's on a gasket mating surface, machine it back to spec. Really all depends on how bad the damage is and the cost of what the shop will charge versus how much a used lower costs.

 

[jtfairlane]

A couple of people surmised that I overtightened the temperature sensor and might have slightly cracked the bottom of the lower intake or something. This is the only thing I think it could be, because I replaced the timing cover/water pump gaskets, and replaced the intake to head gaskets again just to be sure it wasn't a bad gasket (even though they had less than 1000mi on them), and the problem persists.

A leak at the thermostat housing to the intake, or from a just slightly loose upper radiator hose to the thermostat housing can do the exact same thing. Leaks at both locations can puddle at the top of the timing chain cover, and can be harder to notice than you might think. They can even be hard to see! A leak at the upper radiator hose to the thermostat housing might not leak when the engine isn't running or when idling, but leak when there is more pressure at higher rpms. A slightly less than tight hose clamp is all it takes. Try those first, if it fixes the leak then you don't have to pull the intake. If it doesn't, you've lost nothing in the attempt and ruled them out as well.

 

[Stormwalker]

A leak at the thermostat housing to the intake, or from a just slightly loose upper radiator hose to the thermostat housing can do the exact same thing. Leaks at both locations can puddle at the top of the timing chain cover, and can be harder to notice than you might think. They can even be hard to see! A leak at the upper radiator hose to the thermostat housing might not leak when the engine isn't running or when idling, but leak when there is more pressure at higher rpms. A slightly less than tight hose clamp is all it takes. Try those first, if it fixes the leak then you don't have to pull the intake. If it doesn't, you've lost nothing in the attempt and ruled them out as well.

I know exactly what you're talking about. Furthermore, my water neck is a replacement, and doesn't have that little flange or whatever at the radiator hose end, making it even more prone to leak. However, I have checked out the waterneck to intake, and radiator hose to waterneck pretty throughly, and I am reasonably certain that is not the culprit. Furthermore, the leak started immediately after I replaced the sensors (as in first drive afterwards), so it is very likely related to that. But your advice was good, I've had it leak from there a few years ago because of a clamp that was not tight enough. And heck, I'll triple check it just to be sure. Pretty sure the lower intake is coming off to fix this problem though.


Tomcat, good to hear there's a possibility of saving the one I have, like I said it's not a horrible leak, so (hopefully) the damage may not be irreparable. I wouldn't mind picking up a used one for $100 to be sure I don't have any problems with a repaired intake, but I have no idea what to tell places for codes for what I need.

 

[Mr Grim]

One more thing to check is the lower intake bolt that is in the right-front corner...near the hard-line fitting that feeds the heater core. That bolt needs sealant or it will weep fluid....very hard to see or notice unless you are looking for it.
I would make absolute certain exactly where the leak is coming from before taking the lower off. Might save yourself a whole bunch of hassle.

 

[backfocus]

If you haven't pressure checked it, I would highly recommend it. I had a leak recently in the same location and thought at first it was the thermostat housing and after pressure checking it I discovered it wasn't. It was leaking in between the block, head, and lower intake. Here is my post if it helps. http://forums.stangnet.com/showthread.php?t=690924

You can rent the coolant system pressure testers at most automotive parts stores, I got mine at Autozone. One of the best tools I have ever used for diagnostics and finding leaks.

If you have been that route at least you should be able to see where it is leaking from, although you will need a mirror for the underside, especially if all accessories are still on the car.

 

[Stormwalker]

One more thing to check is the lower intake bolt that is in the right-front corner...near the hard-line fitting that feeds the heater core. That bolt needs sealant or it will weep fluid....very hard to see or notice unless you are looking for it.
I would make absolute certain exactly where the leak is coming from before taking the lower off. Might save yourself a whole bunch of hassle.

Ok, I did NOT put sealant on any of the lower intake bolts. Sorry for the retarded question, but when you say right-front corner, you mean the passenger side, towards the front of the motor?

If you haven't pressure checked it, I would highly recommend it. I had a leak recently in the same location and thought at first it was the thermostat housing and after pressure checking it I discovered it wasn't. It was leaking in between the block, head, and lower intake. Here is my post if it helps. http://forums.stangnet.com/showthread.php?t=690924

You can rent the coolant system pressure testers at most automotive parts stores, I got mine at Autozone. One of the best tools I have ever used for diagnostics and finding leaks.

If you have been that route at least you should be able to see where it is leaking from, although you will need a mirror for the underside, especially if all accessories are still on the car.

I did a search (which usually answers my questions) before I posted this thread, and ran across yours right away. What's funny is that mine pretty much leaks from the exact same place yours did, and the first thing I did is replace the lower intake to head gaskets, this time around putting a little RTV around the coolant passages on the gaskets. Unfortunately, my problem persists, and must be something other than a gasket problem. However, I never thought of using a pressure tester, might help to verify with certainty that my theory is correct before I go replacing lower intakes and such.

Thanks again for all this input so far. I will try the sealant around the bolt, and maybe the pressure tester if I can find one (car is stored in a pretty remote location in central/northern MN). If the worst case scenario comes to be and I have to replace the lower intake, does anyone happen to know what kind of Explorer lower would work, or would just any do?