Date: Fri, 2 Jul 1999 02:16:28 -0500
Reply-To: Budd Premack <bpremack@WAVETECH.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Budd Premack <bpremack@WAVETECH.NET>
Subject: HELP NEEDED - Cooling System Flushing
Content-Type: multipart/alternative;
I just sold my 84 GL, conditioned upon changing and flushing the coolant. The PO had not used phosphate-free coolant, and I had not yet gotten around to changing it since I had the van stored all winter after I obtained it last fall. It just seemed incongruous to preach proper maintenance and then sell a van with the wrong coolant, especially to a Newby.
Draining the old coolant and flushing with fresh water went pretty well. The problem is air trapped in the system. I thought I followed proper procedures. I filled the expansion tank with fresh phosphate-free coolant while running the engine at 3000 rpms, with the radiator bleeder screw open three turns, the engine bleeder valve opened and the front end raised about 16 inches on ramps and a sloped driveway. Front and rear heate valves were fully open.
The engine was run long enough for the thermostadt to open, with the temp guage showing in the middle range. The expansion tank was full, with air coming out of the radiator bleeder screw, but no coolant was even sputtering out. The fill tank was also filled to the correct level.
I then replaced the expansion tank cap and shut off the engine in order to try Darrell Boehler's bike pump technique. I took off the small connecting hose from the expansion tank cap and hooked up a proper sized plastic hose fitted to a bike pump. When I pressurized the system with a few strokes on the pump, the radiator gurgled with the sound of escaping air through the bleeder screw. The coolant level in the expansion tank dropped to just below the level of the top large coolant hose, but would not drop any further even though I tried repeated cycles of pressurizing and allowing air to escape out of the radiator bleeder valve. I also had my assistant continue pumping while I observed air escaping from the bleeder valve (gurgling sounds, but no coolant drips) although the coolant in the expansion tank stayed pretty constant at just below the level of the top large coolant hose. I tried the bike pump technique several times, first with the engine bleeder valve open, and then with it closed. Continued pumping of the bike pump did not cause the expansion tank coolant level to drop any further, even though air continued to escape from the radiator bleeder screw.
My suspicion is that there is a crack near the top of the plastic expansion tank. When the radiator bleeder screw was closed, the bike pump disconnected, and the small connecting hose re-attached, the expansion tank coolant level stabilized about 1" below the top of the tank (which is above the top of the large coolant hose), which is exactly where it had been for months with the old coolant.
My major concern is burping enough air out of the system so that the engine does not overheat due to air pockets in the coolant. This already started to happen once during a test run, but this was at least partially solved by adding more coolant, as the level in the expansion tank had dropped a few more inches then. Now the temp guage is still running too warm, about 1/2 way between its normal position of dead center and the high temp warning area on the right side.
Is my problem that I didn't give either the 3000 rpm or the bike pump techniques enough time for the air to bleed out? Should I have removed the radiator bleed screw instead of just loosened it? Is the engine bleeder valve suposed to be open or shut during the bleeding process? Could a crack in the expansion tank be a partial or complete cause for all of this?
For now, (overnight) the van is back up on the front ramps, with the radiator bleeder screw and the engine bleeder valve both closed. My hope is that the air will naturally congregate at the top of the radiator where it can easily be released through the bleeder screw, using the bike pump technique with a cold engine. Also, perhaps the overnight cooling and de-pressurization of the engine will contract the coolant enough so that I can add more coolant to the expansion tank.
All help will be greatly appreciated, especially fast responses, as my buyer is most anxious to get his van for this weekend, and I am most anxious to get paid for it.
Budd Premack
86 Syncro, 73 Super
Minneapolis, MN (Land of Sky Blue Waters)
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