Did you break these connections when you flushed it last year--if so, what did they look like then?

 

no i didn't, this is the first time since i've owned the vehicle. when i first bought it, the reservoir was VERY dirty, with the fluid extremely murky and brown. i did the flush/fill a month or two after i bought the car, so i guess its close to two years..

 

OK, that explains it--in all probability when you flushed it last year it was the first time the coolant had ever been changed; which should be done at a bare minimum of every 5 years, preferably every 2 to 3 years.

The corrosion inhibitors are first thing to break down, once they do the damage you observed is what happens...

There can also be a problem with electrolysis eating away the heater core (see this TSB) when the coolant breaks down to the point that it becomes ionised...

 

thanks cliff, that makes me feel a bit better abt the situation. i couldnt open the link you posted, but (knock on wood) the heater core seems to working fine thus far. i've already replaced one in the f150, so i'm aware of the painstaking process i would be in for.

unfortunately, the further i dive into this job, the more i'm finding wrong.. the other side of that aluminum channel attached to the intake also has a corroded opening around the rubber gasket, although nowhere near as bad and wasn't leaking before. i also found a crack towards the rear driver's side of the manifold. its a tad deep, but doesn't seem close enough to the rear-most bolt or intake port to be affecting anything. will hafta seal that up with some silicone rtv sealant and then slap my new gaskets..

once again, thanks a lot bro, you've been a tremendous help!

 

Clean it up clean, Clean. CLEAN and "glue" it back together with J-B Weld--I did that 4 months and 3500k ago and it's been fine.

I fixed the link, forget to copy the file to my web server (senility)...

 

Senility and web server cannot exist in the same sentence.

 

This same thing just happened to my 2002 gt, but the plastic is pretty much gone in between the rectangular and circle holes in between the aluminum crossover and the plastic. Is there any reason the water shouldn't be mixed between these two water passages?

 

no, just have to keep up with the routine maintenance of flushing the coolant system every 2-3 years as cliff said. with mine, it was obviously neglected for years by the previous owner. i did as cliff suggested and J-B welded a new wall for the hole on the t-stat side, as well as patched up a few other corroded spots, but i can't say it wasn't a painstaking process. almost feel as though it would have been worth replacing, but this was a much cheaper route, and seems to be as reliable, if not more (considering the weld has higher heat tolerance than the plastic).

 

I know this is an older post (almost 2 years), but I just had a problem with my 2003 GT. I *believe* this is where my leak is also.

I tried pulling off the whole bracket/housing and there seems to be one bolt/screw I cannot get to on the very left side of the housing (complete opposite end of the t-stat housing).

Am I going to have to take off the black plastic intake manifold just to get to this one screw and be able to change the lower t-stat gaskets? What a PITA! I'm a little scared to take all the top-end off just to get this one bolt. Seems like a lot of labor for such a small thing.

PLUS, where do you even buy that lower t-stat housing? AutoZone nor Checker, nor Rock Auto even stock it. Is it just a dealer thing? CRAP!!!

 

There is no repair for the "lower t-stat gasket", when it leaks it is because the recess that contains it has eroded as I described above. The only solutions are to clean it and fix it back together with JB-Weld, also as described above, or replace the intake manifold.

BTW as I sold my '03 GT I have a very nearly new FRPP manifold I no longer need--PM me if interested...