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cooling system pressure(normal)

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

dublin19
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dublin19

cooling system pressure(normal)

Post by dublin19 » Mon Sep 02, 2019 10:52 am

Hi all! can someone tell me how many bar or psi pressure is normal in the cooling system when the engine is warm? (if the thermostat is open) for cooling water above 90 degrees Celsius? (petrol turbo 850 v70 s70)



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June
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Re: cooling system pressure(normal)

Post by June » Mon Sep 02, 2019 2:39 pm

Green cap 1.50 bar. June

BTW the black cap found on older Volvo cars like the 1990 240 is .75 bar, both the green and black caps interchange even on my 2004. I ran the black cap until earlier this year when my mechanic insisted on putting the green cap back on and promptly the coolant lines to the oil cooler leaked, and last week the heater core... we figured by using the black cap the boiling temperature only drops by 20°F which is still way overheated. June
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dublin19


My Volvo cars owned
1989 740 GLT ordered
1994 850 4door standard shift ordered
1996 960 ordered
1998 S90 ordered totalled after 3 weeks
1998 V70 GT dealer stock car
2002 S80 T6 ordered totalled
2004 S80 T6 dealer stock car and current car owned

dublin19
Posts: 6
Joined: Fri Mar 29, 2019 6:01 pm
Year and Model: 1997 v70
Location: Zala
Has thanked: 1 time
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Hungary
dublin19

Re: cooling system pressure(normal)

Post by dublin19 » Tue Sep 03, 2019 1:38 pm

June wrote:
Mon Sep 02, 2019 2:39 pm
Green cap 1.50 bar. June

BTW the black cap found on older Volvo cars like the 1990 240 is .75 bar, both the green and black caps interchange even on my 2004. I ran the black cap until earlier this year when my mechanic insisted on putting the green cap back on and promptly the coolant lines to the oil cooler leaked, and last week the heater core... we figured by using the black cap the boiling temperature only drops by 20°F which is still way overheated. June

I have a green cap. Up to 1.5 bar. does this mean that the cooling system is up to 1.5 bar in normal operation?



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June
Posts: 1551
Joined: Wed May 04, 2016 11:18 am
Year and Model: 2004 S80 T6
Location: Jacksonville, Florida
Has thanked: 236 times
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June

Re: cooling system pressure(normal)

Post by June » Tue Sep 03, 2019 1:47 pm

dublin19 wrote:
Tue Sep 03, 2019 1:38 pm
June wrote:
Mon Sep 02, 2019 2:39 pm
Green cap 1.50 bar. June

BTW the black cap found on older Volvo cars like the 1990 240 is .75 bar, both the green and black caps interchange even on my 2004. I ran the black cap until earlier this year when my mechanic insisted on putting the green cap back on and promptly the coolant lines to the oil cooler leaked, and last week the heater core... we figured by using the black cap the boiling temperature only drops by 20°F which is still way overheated. June

I have a green cap. Up to 1.5 bar. does this mean that the cooling system is up to 1.5 bar in normal operation?
Yes. When it is at operating temperature the cap will regulate the system up to 1.50 bars. Anything over 1.50 bars the cap will vent the excess pressure. On a cold winter's day the pressure will be lower at operating temperature where as a 100° muggy Florida day it likely reaches the full 1.50 bars driving in traffic quickly. June


My Volvo cars owned
1989 740 GLT ordered
1994 850 4door standard shift ordered
1996 960 ordered
1998 S90 ordered totalled after 3 weeks
1998 V70 GT dealer stock car
2002 S80 T6 ordered totalled
2004 S80 T6 dealer stock car and current car owned

dublin19
Posts: 6
Joined: Fri Mar 29, 2019 6:01 pm
Year and Model: 1997 v70
Location: Zala
Has thanked: 1 time
Been thanked: 0
Hungary
dublin19

Re: cooling system pressure(normal)

Post by dublin19 » Tue Sep 03, 2019 2:08 pm

June wrote:
Tue Sep 03, 2019 1:47 pm
dublin19 wrote:
Tue Sep 03, 2019 1:38 pm
June wrote:
Mon Sep 02, 2019 2:39 pm
Green cap 1.50 bar. June

BTW the black cap found on older Volvo cars like the 1990 240 is .75 bar, both the green and black caps interchange even on my 2004. I ran the black cap until earlier this year when my mechanic insisted on putting the green cap back on and promptly the coolant lines to the oil cooler leaked, and last week the heater core... we figured by using the black cap the boiling temperature only drops by 20°F which is still way overheated. June

I have a green cap. Up to 1.5 bar. does this mean that the cooling system is up to 1.5 bar in normal operation?
Yes. When it is at operating temperature the cap will regulate the system up to 1.50 bars. Anything over 1.50 bars the cap will vent the excess pressure. On a cold winter's day the pressure will be lower at operating temperature where as a 100° muggy Florida day it likely reaches the full 1.50 bars driving in traffic quickly. June
Thanks for the quick response! I measure the exhaust gas in the expansion tank sure because my upper radiator hose is hard enough.
that's why I questioned the amount of system pressure.



User avatar
June
Posts: 1551
Joined: Wed May 04, 2016 11:18 am
Year and Model: 2004 S80 T6
Location: Jacksonville, Florida
Has thanked: 236 times
Been thanked: 124 times
United States of America
June

Re: cooling system pressure(normal)

Post by June » Tue Sep 03, 2019 2:24 pm

dublin19 wrote:
Tue Sep 03, 2019 2:08 pm
June wrote:
Tue Sep 03, 2019 1:47 pm
dublin19 wrote:
Tue Sep 03, 2019 1:38 pm



I have a green cap. Up to 1.5 bar. does this mean that the cooling system is up to 1.5 bar in normal operation?
Yes. When it is at operating temperature the cap will regulate the system up to 1.50 bars. Anything over 1.50 bars the cap will vent the excess pressure. On a cold winter's day the pressure will be lower at operating temperature where as a 100° muggy Florida day it likely reaches the full 1.50 bars driving in traffic quickly. June
Thanks for the quick response! I measure the exhaust gas in the expansion tank sure because my upper radiator hose is hard enough.
that's why I questioned the amount of system pressure.
If the upper hose is instantly tight with pressure, you need to check for exhaust gasses immediately. The pressure should build with temperature and dissipate quicky if the radiator is cooled quickly. Such as spraying the radiator with a garden hose causing a rapid temperature drop or getting on the expressway on a 0° day. June


My Volvo cars owned
1989 740 GLT ordered
1994 850 4door standard shift ordered
1996 960 ordered
1998 S90 ordered totalled after 3 weeks
1998 V70 GT dealer stock car
2002 S80 T6 ordered totalled
2004 S80 T6 dealer stock car and current car owned

dublin19
Posts: 6
Joined: Fri Mar 29, 2019 6:01 pm
Year and Model: 1997 v70
Location: Zala
Has thanked: 1 time
Been thanked: 0
Hungary
dublin19

Re: cooling system pressure(normal)

Post by dublin19 » Tue Sep 03, 2019 2:56 pm

June wrote:
Tue Sep 03, 2019 2:24 pm
dublin19 wrote:
Tue Sep 03, 2019 2:08 pm
June wrote:
Tue Sep 03, 2019 1:47 pm


Yes. When it is at operating temperature the cap will regulate the system up to 1.50 bars. Anything over 1.50 bars the cap will vent the excess pressure. On a cold winter's day the pressure will be lower at operating temperature where as a 100° muggy Florida day it likely reaches the full 1.50 bars driving in traffic quickly. June
Thanks for the quick response! I measure the exhaust gas in the expansion tank sure because my upper radiator hose is hard enough.
that's why I questioned the amount of system pressure.
If the upper hose is instantly tight with pressure, you need to check for exhaust gasses immediately. The pressure should build with temperature and dissipate quicky if the radiator is cooled quickly. Such as spraying the radiator with a garden hose causing a rapid temperature drop or getting on the expressway on a 0° day. June
I only feel the hose hard with the warm engine running. above 85-90 degrees Celsius. I would like to know how hard the top radiator hose must be if the engine is very warm



User avatar
June
Posts: 1551
Joined: Wed May 04, 2016 11:18 am
Year and Model: 2004 S80 T6
Location: Jacksonville, Florida
Has thanked: 236 times
Been thanked: 124 times
United States of America
June

Re: cooling system pressure(normal)

Post by June » Tue Sep 03, 2019 3:03 pm

dublin19 wrote:
Tue Sep 03, 2019 2:08 pm
June wrote:
Tue Sep 03, 2019 1:47 pm
dublin19 wrote:
Tue Sep 03, 2019 1:38 pm



I have a green cap. Up to 1.5 bar. does this mean that the cooling system is up to 1.5 bar in normal operation?
Yes. When it is at operating temperature the cap will regulate the system up to 1.50 bars. Anything over 1.50 bars the cap will vent the excess pressure. On a cold winter's day the pressure will be lower at operating temperature where as a 100° muggy Florida day it likely reaches the full 1.50 bars driving in traffic quickly. June
Thanks for the quick response! I measure the exhaust gas in the expansion tank sure because my upper radiator hose is hard enough.
that's why I questioned the amount of system pressure.
Really tight. Also hose should stay tight after engine has been shut off. If the pressure disappears instantly upon turning the engine off is another indication of trouble. The pressure should slowly dissipate as the engine cools and the pressure should build with heat as the engine warms up. It's due to the water expanding with heat / contracting as cooled. June


My Volvo cars owned
1989 740 GLT ordered
1994 850 4door standard shift ordered
1996 960 ordered
1998 S90 ordered totalled after 3 weeks
1998 V70 GT dealer stock car
2002 S80 T6 ordered totalled
2004 S80 T6 dealer stock car and current car owned

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