Coolant Leak around intake manifold
 

Hi Mustang owners,

I'm new to the group, and own a 2002 Mustang GT, 4.6 Lt. I noticed the GT was using coolant after only owning it a few days. The GT is my son's first car we got about 3 months ago. After observing the GT using more coolant, I decided to inspect all hoses, the tank and the radiator, no clue. Then I noticed residual coolant sitting on the engine, buried under the intake manifold. It appeared to be coming from the drivers side of the manifold, directly where the thermostat housing is. Upon removing the hose, and the thermostat, thinking it could be a faulty thermostat, I see some of a seal or gasket sticking out (attached picture).

I researched other GT Mustang intake manifold topics on the web, and see we clearly have the replacement "cast aluminum crossover" section to the plastic manifold, introduced in 2002, the same year as this GT.

So, I dig further, and know I must have to remove the manifold; I removed all interference, and have the manifold out. I noticed cracking/deformation around the inlet area, that mates up with the engine block, and the seals are brittle and worn (added picture).

If any Mustang mechanics, enthusiasts etc...have any tips or guidance from replacement, to prepping area, surface area, etc...I'd really like your input.

I've ordered a replacement intake manifold, water pump and gaskets in the meantime.https://cimg5.ibsrv.net/gimg/mustang...6d628406b3.jpgThermostat housing with seal at crossover section of manifold
https://cimg1.ibsrv.net/gimg/mustang...0676f58627.jpgintake manifold bottom side seal
https://cimg0.ibsrv.net/gimg/mustang...f1b11b23d6.jpgintake manifold bottom side seal other side
https://cimg3.ibsrv.net/gimg/mustang...62f7127125.jpgIntake manifold removed


I did disconnect the (2) fuel pump/line electrical connections behind the drivers door to bleed off any excess fuel pressure. The fuel injectors look fine, but are there any worries I need to consider during reassembly?

Thank you!
Eric

direct swap, make sure head surface is clean and free of debris. Disable the fuel, remove the spark plugs and spin the motor over a few times to make sure no coolant spilled into the intake runners during removal

WhiteFoxGT, thanks for the reply. Sounds like I'm on the right path.

Anything particular to use for the cleaning head surface? I was thinking along the lines of scotch brite, putty knife, or whizz pads.

Do I use silicone or any sealant between the gaskets and intake manifold?

As you are well aware of now the intakes/manifolds are inherit problem with the 4.6L

Anyhow the swap is not that difficult for cleaning the surface be careful the heads are aluminum , brake clean and a scotch brite is good forget the putty knife unless it is plastic.

No silicone or sealant is necessary, as long as its not pitted or corroded, after cleaning i like to put a little WD 40 on the gasket "O"rings it allows the o-ring to seat. Spray on your finger and wipe the o-rings.

If you have been shopping for a manifold i'm sure you have ran across the infamous Dorman, by far the cheapest manifold on the market, i have never used one but everyone warns and bitches about it, a Ford Racing manifold is going to cost ya $300.00

Make sure you check the spark plug wells for antifreeze blow them out with compressed air, remove and replace should only take an experienced mechanic 2 -4 hours

Cleaning now, but pitting
 

WJL, Thanks for the reply and tips. So, as I was cleaning the surface area yesterday evening, I'm noticing pitting and corrosion around the front inlets of the block. I used some 0000 fine steel wool for a smooth surface, but the pitting is still there.

Any ideas for sealant before I place the gaskets and manifold on to prevent future leaks?

I found an ATP manifold on Rockauto for $147, APEX gaskets for about $17, and an AIRTEX water pump for about $23 -

https://cimg4.ibsrv.net/gimg/mustang...0ca95bc5a2.jpgDrivers side, front
https://cimg5.ibsrv.net/gimg/mustang...c272e71c57.jpgPassengers side, front

I wouldn't use anything but Fel-Pro or Ford OEM gaskets, but that's me, you will need to use a SMALL and i mean a small amount of RTV to fill in the pitted area and only the pitted areas.

I have seen worse, Good luck

Looked at the ATP manifold you wouldn't need gaskets with that manifold the O-rings are integral to the manifold very similar to the DORMAN, i have never used one but i don't like the integral o-rings.

I realize it's half the cost but you only get what you pay for I'd be looking at American Muscle for replacement manifolds

I'd use something like JB Weld or their WaterWeld in the pitted area to make sure it seals well!!:icon_worthy:

Also use distilled water when ya refill it!!:icon_toast:

dont use any kind of jb weld

the slightest bit or rtv sealant on the area would work, i honestly have never used anything but just new gaskets...dry.. for all the mod motors ive done, and i guarantee its more than anyone in this post so far lol