Engine: 70 T5: - Coolant flowing through overflow hose

pt5on · Jul 21st, 2011, 15:19

Hi,

I have a V70 1999 T5. I've just noticed that coolant is being pumped through the small-bore overflow pipe from the top of the radiator back into the expansion tank when the engine is hot and revved above an idle.

I'm assuming that this is caused by pressure from the water pump when the revs are raised forcing coolant through the thermostat towards the radiator, and some of the coolant is taking the route up the expansion hose back to the bottle rather than all going through the radiator. Could anyone confirm if this normal behaviour or not??

Now I'm worried that there's a problem brewing. The top hose does feel very hard when up to temperature - I'm wondering if this is a symptom of
a) head gasket failure pressurising the cooling system, or
b) blocked radiator

The engine temp is normal (steady at half-way). Thermostat has been replaced in the last few years. Did have a weep in the rad a while back that I fixed with RadWeld (I know..!)

Any thoughts greatly appreciated. Can anyone recommend a DIY pressure tester for the cooling system that could confirm/disprove that it is being pressurised by a HG failure.

Thanks.

Luxobarge · Jul 21st, 2011, 15:39

Perfectly normal - don't panic!

pt5on · Jul 21st, 2011, 15:42

Thanks Luxobarge,

I've had the car for five years - it's funny the things you "suddenly" notice.

Andy Northface · Jul 21st, 2011, 21:39

Quote:

Originally Posted by Luxobarge

Perfectly normal - don't panic!

That's what I thought as well!

Jul 21st, 2011, 15:19	#1
pt5on New Member Last Online: Oct 19th, 2011 17:17 Join Date: Jan 2007 Location: Hatfield, Herts	Coolant flowing through overflow hose Hi, I have a V70 1999 T5. I've just noticed that coolant is being pumped through the small-bore overflow pipe from the top of the radiator back into the expansion tank when the engine is hot and revved above an idle. I'm assuming that this is caused by pressure from the water pump when the revs are raised forcing coolant through the thermostat towards the radiator, and some of the coolant is taking the route up the expansion hose back to the bottle rather than all going through the radiator. Could anyone confirm if this normal behaviour or not?? Now I'm worried that there's a problem brewing. The top hose does feel very hard when up to temperature - I'm wondering if this is a symptom of a) head gasket failure pressurising the cooling system, or b) blocked radiator The engine temp is normal (steady at half-way). Thermostat has been replaced in the last few years. Did have a weep in the rad a while back that I fixed with RadWeld (I know..!) Any thoughts greatly appreciated. Can anyone recommend a DIY pressure tester for the cooling system that could confirm/disprove that it is being pressurised by a HG failure. Thanks. __________________ Paul '99 V70 Classic T5 SE Auto Last edited by pt5on; Jul 21st, 2011 at 15:39.

Jul 21st, 2011, 15:39	#2
Luxobarge Premier Member Last Online: Today 10:29 Join Date: Jan 2011 Location: Horne (Nr. Horley)	Perfectly normal - don't panic! __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.

Jul 21st, 2011, 15:42	#3
pt5on New Member Last Online: Oct 19th, 2011 17:17 Join Date: Jan 2007 Location: Hatfield, Herts	Thanks Luxobarge, I've had the car for five years - it's funny the things you "suddenly" notice. __________________ Paul '99 V70 Classic T5 SE Auto

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