Which Synthetic for 3800 Series II?

[Merkava_4]

Originally Posted By: Striker
I'm still on the fence about the dexcool eating thru the lower intake manifold gaskets. I haven't done any deep research but on all the impala forums nowhere does it state that dex cool itself was the route of the problem for the gaskets taking a [censored]?


My Buick has had Dex-Cool in it ever since it rolled off the assembly line in 2000 and I've never had any problems with it.

 

[InvalidUserID]

I've got 180+k miles on my '96 Camaro with the 3800 II engine. It was my college commuter car that drove almost 70 miles round trip per day and it never gave me any issues other than a water pump here or leaking main seal there.

Early on I did 3k oil changes on dino but the past 5 years or so it's been on synthetics. Over the 10 years I've had the car, I must have tried every oil and have seen/felt no noticeable difference. Oil analysis shows the engine is still strong and very clean (did a few ARX cycles years ago).

As for coolant, I did have a upper intake gasket that needed replacement shortly after I purchased the car and it was fixed (under warranty). No sure if the Chevy dealership used the OEM gaskets or some improved ones but I've been changing the coolant every two years and haven't had issues since.

 

[04SE]

Originally Posted By: Striker
I'm still on the fence about the dexcool eating thru the lower intake manifold gaskets. I haven't done any deep research but on all the impala forums nowhere does it state that dex cool itself was the route of the problem for the gaskets taking a [censored]?


The problem is two fold. The LIM gaskets fail and the UIM gasket fails. BUT, the UIM gasket fails as the plastic UIM warps because of a VERY poor EGR design.

Ask me how I know... I spent a morning elbow deep in our 2005 Impala (L36) changing LIM gaskets, UIM gasket and installing a new/revised UIM. After 4 years and ~50k miles, the Dex-Cool had already formed MAJOR deposits. I plan on changing the Dex-Cool every 12k-15k miles. At least a good drain/fill.

 

[Striker]

I guess I may as well do the UIM gaskets as well as the lower if that's the case. I'll try and get rid of the dexcool for sure. I see the build up on my 24K miles WS6 just around the dip stick, let alone what goes on inside. I have no idea why GM uses that [censored].