Radiator flush pressure test
12-06-2015, 11:34 PM
#1
Rennlist Member
Thread Starter
Radiator flush pressure test
Starting to put things back together.
Any tips on flushing or testing the radiator while it is out of the car?
Thnx
Any tips on flushing or testing the radiator while it is out of the car?
Thnx
12-07-2015, 08:44 AM
#2
Team Owner
stick a hose in the bottom hole then let the water flush out the top.
then back wash the radiator to wash any debris from back to front.
this should remove a bunch of small stones
then back wash the radiator to wash any debris from back to front.
this should remove a bunch of small stones
12-07-2015, 10:56 AM
#3
Rennlist Member
To pressure test the radiator you need to cap the main connections somehow and use the small vent connection to pressurise the radiator to the expansion cap set point [15 psig I believe]. You can then let the thing sit there for half an hour or more and ensure it holds pressure.
'You can squirt soapy water over the tubes and more specifically over the end plate where the tubes enter the header boxes and look for signs of bubbles. The most effective indicator if you can rig it, is to fully immerse the pressurised radiator in a bath tub or other large receptacle and simply look for any sign of bubbles [a fart in a bath tub type of thing].
Rgds
Fred
'You can squirt soapy water over the tubes and more specifically over the end plate where the tubes enter the header boxes and look for signs of bubbles. The most effective indicator if you can rig it, is to fully immerse the pressurised radiator in a bath tub or other large receptacle and simply look for any sign of bubbles [a fart in a bath tub type of thing].
Rgds
Fred
12-07-2015, 06:52 PM
#5
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Follow the previous guidance on mechanical cleaning and reverse-flushing both inside and out.
At the bottom (discharge) nozzle, you can stick a small inspection mirror in and see the condition of the bottom tubes. Those tend to be coldest, and at the bottom they also tend to gather any precipitate and minerals that plate out, so would be the extreme worst case for seeing what's inside the rest of the radiator. It's aluminum, with 'turbulator' ribs formed on the insides of the tubes. Those add surface area inside, and disturb the coolant flow to improve heat tansfer. They are also handy little recesses that allow pockets of any contaminants (minerals. precipitates) to drop or plate out as the coolant temperature drops. So mechanical cleaning is not a complete solution (so to speak...) Sometimes chemical cleaning wil help, but there are issues with corrosive chems and hide-out around the tank end seals that demand some pretty serious rinsing.
Probably a good idea for pressure testing to test it in place, along with all the rest of the hoses and connections in the system. Many parts stores will free-rent a pressure tester that screws onto the reservoir where the cap usually sits. Get everything full, pressurize to 15 PSI, look for trickles of water. Best done engine cold, so you can explore the whole system for leks without getting burned, more imporatntly so any leaking water doesn't evaporate before you discover it.
Otherwise...
Home Depot sells expanding rubber pipe plugs that can be used to block the main coolant nozzles on the radiator. At the top of the radiator is the little air-vent nozzle that fits handily into 8mm hose. 8mm is 5/16+0.003", so you can make a little assembly with 'murikan tube fittings that will let you pressurize the radiator with air after you fill it with water. Use a mini pressure regulator with a gauge on it, or even just a bicycle tire pump to get the pressure to 15 PSI. Look for leaks.. Hint: it will be wet where it has leaks... The other way is to just put 15 PSI air in it and search with a spray bottle with some soapy water, looking for bubbles. A childrens play pool is handy if you want to submerge it and look for bubbles. That's pretty much what the radiator shop will do.
At the bottom (discharge) nozzle, you can stick a small inspection mirror in and see the condition of the bottom tubes. Those tend to be coldest, and at the bottom they also tend to gather any precipitate and minerals that plate out, so would be the extreme worst case for seeing what's inside the rest of the radiator. It's aluminum, with 'turbulator' ribs formed on the insides of the tubes. Those add surface area inside, and disturb the coolant flow to improve heat tansfer. They are also handy little recesses that allow pockets of any contaminants (minerals. precipitates) to drop or plate out as the coolant temperature drops. So mechanical cleaning is not a complete solution (so to speak...) Sometimes chemical cleaning wil help, but there are issues with corrosive chems and hide-out around the tank end seals that demand some pretty serious rinsing.
Probably a good idea for pressure testing to test it in place, along with all the rest of the hoses and connections in the system. Many parts stores will free-rent a pressure tester that screws onto the reservoir where the cap usually sits. Get everything full, pressurize to 15 PSI, look for trickles of water. Best done engine cold, so you can explore the whole system for leks without getting burned, more imporatntly so any leaking water doesn't evaporate before you discover it.
Otherwise...
Home Depot sells expanding rubber pipe plugs that can be used to block the main coolant nozzles on the radiator. At the top of the radiator is the little air-vent nozzle that fits handily into 8mm hose. 8mm is 5/16+0.003", so you can make a little assembly with 'murikan tube fittings that will let you pressurize the radiator with air after you fill it with water. Use a mini pressure regulator with a gauge on it, or even just a bicycle tire pump to get the pressure to 15 PSI. Look for leaks.. Hint: it will be wet where it has leaks... The other way is to just put 15 PSI air in it and search with a spray bottle with some soapy water, looking for bubbles. A childrens play pool is handy if you want to submerge it and look for bubbles. That's pretty much what the radiator shop will do.