Cooling System Flush and Fix

Last spring when I started getting the ‘Vette in proper running order, it became quickly apparent there were some cooling system issues. Most notably the heater core was leaking as evidenced by the strong smell of antifreeze in the interior. I’ll never forget the previous owner’s frantic affirmation of his used-car-salesmanship when I mentioned this after the test drive – “the heat works!” No shit sherlock. Anyway, I felt it was safe to assume this was leaking due to the coolant being negligently left in service far too long, becoming acidic and causing corrosion. I was looking forward to logging some drive time in the new toy so I decided replacing the heater core (and yanking the dash out) was a job that could wait until the boredom of winter set in. So I bypassed it and moved on to flushing the ridiculously nasty DexCool out of the green beast.

Since I had the water pump off to replace the timing cover oil seals I thought it prudent to go ahead and flush the cooling system as well as possible. This lovely brownish liquid is what I was able to flush out of the “burper” line. I shit you not, this is only the crap that drained out of that tiny line! The rest of the coolant went into a catch pan under the radiator.


This so-called “burper” line is made up of 3/8″ radiator hose crimped to some 1/4″ aluminum tubing that serves to (you guessed it) burp the air from the rear of the cylinder heads and high point of the radiator up to the pressure reservoir. See the highlights in the image.


Unfortunately after several hours of trying to fish welding wire and all sorts of other stuff through the bends in the metal line, I was still unable to get it cleaned to my satisfaction. While it pained me to cut the factory cooling lines up I found that a brass tee, 6 feet of 3/8″ radiator hose and some clamps and sta-ties resolved this nicely. I’m confident this will prevent air pockets from accumulating in the cylinder heads.

I’m also confident I no longer need to have the fans hard-wired on high all the time. While this seems like an ingeniously cheap way to keep the engine cool (if you have missing teeth and your phone ringtone is Dueling Banjos), given the relative ease with which the fan turn-on temps can be adjusted in the ECM calibration I’m inclined to file this “trick” away in the library of good intentions turned into bad ideas.


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