Changing the coolant. Tips?

[TrevShand]

I pulled the my 1994 in to my garage yesterday, and an hour or so later, I went out to find a stream of coolant running down the garage. Took the front bumper cover off today and all of the coolant reservoirs are filthy. Since all of the hoses are fine it seems, my guess is we just have blockage in the lines. So I figure I'll blow out the small lines that go to the reserviours then fluch and fill it until it goes clear. Anything else I should think of or do? What coolant do you recommend once everything is finished?

Thank you.

Trevor

 

[efnfast]

I would put a pressure tester on it and see if there is a leak - i don't know how you just develop a blockage in the lines to the point where it all of a sudden starts pushing out coolant unless a hose collapsed or something really bad just went through your coolant system

With respect to coolant, Gen 4/5s use HOAT like Zerox G05. I've never been too sure what Gen 1/2s use. In mine (as well as all new engine builds I do for my race cars) I use Prestone all-makes anti-freeze ... it's never given me any issues in like 25yrs of building cars.

That said, if you don't know what's in there, make sure you flush the hell out of it as a lot of residual coolant hides in the block and you don't want to mix coolant types or bad things can happen (e.g., mixing HOAT and OAT can cause the coolant gel up and really ruin your day)

 

[daveg]

^^^^ I second pressure testing before putting the car back together.

 

[Steve-Indy]

Agree with testing first.

Most of the overflow situations that I have encountered on Gen I & II Vipers are related to a loss of vacuum on cooldown coupled with failure to monitor both the pressure bottle and the overflow bottle fluid levels for several drive cycles after servicing the coolant. A small hose clamp placed on the rubber hose coming off of the neck of the pressure bottle will often fix the vacuum leak...noting that a second clamp downstream at the next rubber-to-aluminum tube is sometimes required. I also like to use a new pressure cap with coolant change.