Originally Posted By: Squishy
I haven't really kept up with the intake gasket problems, although I probably should with the 3.4 in our minivan. Has it been confirmed that Dex-Cool is at least a leading contributor to the failure? If so, is it possible to completely flush it out and replace with conventional coolant, or will deposits still form?
"Deathcool" is definetly a contributing factor to the intake gasket failures in these motors, although it's not the only problem. Loose lower intake manifold bolts are often found upon disassembly as well. In fact, GM offers replacement intake manifold bolts with Thread-locker impregnated threads as part of the fix for this issue plus a redesigned intake gasket.
Despite persistant myths to contrary, Dexcool equipped vehicles can be converted to conventional green coolant after a through flushing with no adverse effects. Far easier to flush out clean Dexcool
before it turns into a red muck and takes the radiator with it.
Mind you, converting to green coolant does not necessarily guaranteed the intake gasket won't fail anyway. However, the chances are much better that it will happen at 150,000 miles rather than 60,000 miles, (or less in some cases). Just remember to monitor the overflow tank for any suspicous drop in the coolant level.
Aside from the intake gasket problems they are pretty decent engines otherwise.
Ford had it's share of defective intake manifolds with the 4.6 engine, and Toyota has their well known sludging problems.