Dex-Cool conversion

[sas4ever]

so I just bought a 98 grand prix gt 3.8..it has a 147k.. I want to do a dex-cool flush and convert to universal.. what do I need to do.. also anything I should be on the watch for.. all responses are appreciated..

[skitchin]

I don't know much about this but what I have heard is that you have to flush very thoroughly with water a time or two until it's good and clear, then put the new stuff in. You absolutely do not want to cross contaminate the two - dexcool is not compatible with green antifreeze and will turn to sludge and cause major engine failure.

[White93z34]

Pull the heater hoses off the engine and be sure to flush the heater core out as well, also be prepared to do a waterpump should the need arise.

[Schurkey]

[OneBadCutt]

Peak global gold, compatible with any color. How do you know if someone hasn't already done that? I highly doubt with over 100k miles the water pump has never been replaced and that fixed.

[Schurkey]

Once the flush is done, don't forget to pull the radiator AND THE BLOCK drains to remove the flush water. Failure to do this will likely result in too-little antifreeze protection, as well as "trapped" sediment still remaining in the block.

 

Some Buick engines don't have block drains; Buick engineers must have been on drugs to make some of those mistakes. Aluminum oil pump, overhung distributor drive gear on the cam, etc.

[RobertISaar]

IIRC, on the 3800s and its derivatives, the knock sensor(s) are the block drains?

[Schurkey]

IIRC, on the 3800s and its derivatives, the knock sensor(s) are the block drains?

Wouldn't surprise me. My Chevy pickup has one block drain "plugged" with a knock sensor. I know that some years, some Buick engines did not have block drains at all, and other years/other engines did have them. I've never had the opportunity to look at "accessible" no-block-drain blocks to see if the bosses are present, so that the drain holes could be drilled and tapped; or if there are no bosses cast into the block at all.

[Imp558]

IIRC, on the 3800s and its derivatives, the knock sensor(s) are the block drains?

 

Yup, freaked me right out when I lost a piece of masking tape in one painting the block. Had to blow air down through to get it back out. L67