Originally Posted By: ffl
Why Dexcool? The consensus at that time seemed to be go with a different product like Peak GL.
Dexcool is great stuff in the right engines, IMHO this isn't one of them.
Engines with dry intakes and pressurized tanks instead of a radiator cap and overflow bottle do very well with it, wet intakes and caps on the radiator itself are the ones that seem to have issues when they do occur.
You need to pressure test the system but that wont find a faulty cap unless they have a cap adapter for the tester. Stant has been making some real questionable stuff over the last few years, their caps and thermostats are a source of headaches.
Go OEM on these parts only, a thermostat with no jiggle valve (OEM has one) can cause problems when filling and leave air in the system that will take a long time to purge itself, it seems to get trapped near the heater hose connections up near the alternator.
The elbows are a real PITA as someone pointed out, they can weep so little you never see it. If you ever get whiff of coolant once in a while but see nothing its usually these, Again GM OEM only on these although there are some new aluminum ones on the market use GM O Rings on them with a small amount of RTV on the O Rings especially if there is any sign of corrosion where the rings seat.
Felpro has been selling the OEM like plastic frame gaskets (Part # MS958091) and continue to do so along with the new higher priced new aluminum design (Part # MS98014T).
The plastic frame ones are as iffy as it gets, the OEM ones didn't only not like Dexcool (the coolant was not really the major issue as much as it was poor gasket design but it certainly didn't help) but were a poor design from the get go, the seal itself tended to "walk" away from the frame over time and start leaking.
The aluminum frame are superior and seems to have cured the problem long term. Rock Auto sells the ACDELCO Part # 89017816 which is identical to the new ones from the dealer.
These or the dealer stocked ones are the gasket to use in these engines, the "green" seals are Dexcool proof but they don't get rid of the radiator cap which is apparently the major source of Dexcool issues.
The sealing tabs from GM are the best, a just as effective alternative is Barsleak Gold which is the same product (ginger root) by the same manufacturer but in an easier to use powdered form. One tube of the powder is all you need, IMO this should be used in these wet manifold GM engines like it is the N* from day one, stay clear of the metallic sealers.
