I have a coolant leak in my bipass hose

ANONYMOUS

MEMBER
1997 NISSAN QUEST
190,000 MILES

I have a coolant leak in my bipass hose. What are the steps in replacing it?

Saturday, November 17th, 2012 AT 1:17 PM

1 Reply

HMAC300

MECHANIC
48,601 POSTS

Drain t he clooling system, and replace the hose. Fill with coolant then follow these steps.
1. Loosen� engine� and� radiator� air� relief� plugs.� Remove� heater� pipe� air� relief� cap.� See Fig.� 4�.� Connect� one� end� of� 40"� clear, � heat� resistant� hose� to� heater� pipe� relief.� Fill� coolant� reservoir� to� MAX� mark� and� place� hose
from� heater� pipe� air� relief� into� coolant� reservoir.� Ensure� hose� is� below� coolant� level� at� all� times.
2. Slowly� add� coolant� through� radiator� filler� neck, � allowing� several� minutes� for� air� to� escape.� When� coolant� starts� to� drip� from� radiator� air� relief� plug, � close� plug.� Tighten� plug� to� 15 19� ft.� Lbs.� (20 26� N.M).
3. Continue� adding� coolant� while� gently� moving� upper� radiator� hose� up� and� down� until� coolant� level� no� longer� drops� in� filler� neck.� Place� wire� under� radiator� filler� cap� negative� pressure� relief� valve.� See Fig.� 6�.� DO
NOT� install� cap� at� this� time.
4. Start� engine� and� run� at� 2000� RPM� for� 10 15� minutes� or� until� lower� radiator� hose� becomes� hot.� If� coolant� comes� out� of� engine� air� relief� plug, � close� plug.� Tighten� plug� to� 15 19� ft.� Lbs.� (20 26� N.M).� If� coolant� in
radiator� neck� lowers, � add� coolant.� If� coolant� overflows� filler� neck, � install� radiator� cap� (with� wire� installed).
5. Close� engine� air� relief� plug� if� not� already� done.� Stop� engine� and� allow� to� cool� down� completely.� Refill� radiator� and� reservoir� as� necessary.� Ensure� radiator� cap� (with� wire)� is� installed.� Start� engine� and� warm� to
operating� temperature.� If� engine� temperature� raises� above� normal, � stop� engine� and� repeat� this� step.

NOTE: Ensure� coolant� level� in� reservoir� tank� is� maintained� at� MAX� mark� for� the� following� steps.

6. On� vehicles� without� rear� heater, � ensure� temperature� control� lever� is� in� full� HOT� position.� Select� any� fan� speed� and� mode� except� OFF.� Run� engine� at� 3000� RPM� for� 5� minutes� or� until� outlet� air� is� hot.� Repeat� this
step� at� least� 3� times.� Ensure� no� water� noise� is� present� in� heater� core.
7. On� vehicles� with� rear� heater, � run� engine� at� 3000� RPM� with� front� temperature� control� lever� in� full� COLD� position.� Move� rear� temperature� control� lever� to� full� HOT� position.� Select� any� fan� speed� except� OFF.� Run
engine� 5� minutes� or� until� rear� outlet� air� is� hot.
8. Move� rear� temperature� control� lever� to� full� COLD� position.� Move� front� temperature� control� lever� to� full� HOT� position.� Select� any� fan� speed� and� mode� except� OFF.� Run� engine� 5� minutes� or� until� front� outlet� air� is
hot.� Repeat� steps� 7)� and� 8)� at� least� 3� times.� Ensure� no� water� noise� is� present� in� front� or� rear� heater� core.
9. On� models� equipped� with� automatic� A/C, � operate� engine� at� 3000� RPM� with� front� climate� control� set� at� 60°F� and� rear� A/C� control� unit� temperature� switch� to� full� WARM� position� with� fan� on� for� 5� minutes� or� until
rear� outlet� air� is� hot.� Turn� rear� control� unit� to� full� COOL� position� and� set� front� climate� control� to� 90°F� until� front� outlet� air� is� hot.� Repeat� process� at� least� 3� times� until� no� water� noise� is� heard� at� heater� core.
10. On� all� models, � stop� engine.� Fill� coolant� reservoir� to� MAX� mark.� Let� engine� cool� down.� Remove� radiator� cap� and� remove� wire� from� negative� pressure� valve.� Fill� radiator� as� necessary� and� reinstall� radiator� cap.
Remove� hose� from� heater� pipe� relief� and� quickly� install� cap� on� pipe.� Fill� reservoir� as� necessary� and� install� reservoir� cap.

Images (Click to make bigger)