Sorry for picking Will, those are some NASTY gaskets! Did they see alot of high temps such as at the track?. Either way thats remarkable for 30K miles. Were You throwing an orange fog behind ya?

John.... Similar to my thoughts Those intake runners should have been leaking..although if only wicking.. then the failure would have only been slight.

I've yet to notice the wicking with gaskets I've changed. GM changed the design to be a more sturdy gasket. Instead of changing the coolant. They are aware the coolant isn't up to spec...but they changed only one gasket on the motor.

Venom, these aren't my car. I don't have a 3800 that ever saw a drop of DEX. My cars are 93 and 95. DEX started in 96. These are off EK98'* car. I pulled them myself. They were just starting to foul the plugs when we went in there.

These are NOT uncommon. These are very typical DEX-exposed LIM gaskets. I've seen MANY on this Forum that look just like this or worse.

Pics quoted over to page 4:

You said this was your car, you dont ever bother to check your coolant from time to time or just dont ever until now? well just think the radiator looks like that, just think whats in the motor cooling passages and the UIM cooling holes and the water pump. I think I would replace the water pump and also clean the whole system out the best you can. Wow that is very serious. - in short term check your cooling system every 3000 miles like your oil. LOL Oh Also that looks like a mixture between DEXCool and a different type of Coolant mixed together. Thats what happens when you mix DEXCool and Non-Dexcool coolants together. Seen it happen on alot of different GM owners that dont know any better.

As for the thread starter...it looks like sealing tabs were added to the dex @ one time...

I've seen both green & dex eat away the LIM'*...the cure seems to be the metal LIM gaskets...

Dex supposedly has OAT for additives, whereas like Zerex G-05, Motorcraft Gold or Mopar Long Life has H-OAT or a G-05 additive which does not react to air like regular Dex with just an OAT additve.
The best way to see if a coolant is OAT, is to check the ingredients. If it lists 2-EHA..than you have a OAT..just like Dex.

One thing about G-O5, is that it tolerates cavitation and hard water better than the OAT blends as well as air in the system. It also is precharged...

Prestone all makes has 2-ethyl hexanoate. Is that 2-EHA?

How long does it take for dex to accumulate gasket eating acids?

I drain and fill my radiator every 6 months. The dex always looks like cherry flavoured CoolAid.

MAC.. I doubt you'll ever need to worry with that maintenance schedule. It'* tough to say when the bad effects start. 6 months should not be an issue though.

Why do that every 6 months when you can ditch it completely and let it go at least a couple years?

I have converted recently from Dex Cool to the Green stuff, i will NEVER run that orange **** in any of my vehicles ever again, it wreaks utter havoc on gaskets, my LIM gasets at 139,000 kilometers looked like garbage, i was indeed consuming a bit of coolant down an intake passage on cylinder 2 I do belive.
They were collapsed worse than the ones willwren just showed.
YET the gaskets in my 93 at 179,900 kilometers looked like new, NOT a single issue...seems the ratio of failed or failing gaskets on dex vehicles to failing or failed on Glycol vehicles is high.