Volvo S70 Made from 1998 to 2000, this sporty model replaced the 850 sedan and instantly became a hit.

99 S70 2.4 overheat/boil over

Old 06-08-2017, 08:33 AM
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Join Date: Jul 2013
Posts: 13
Default 99 S70 2.4 overheat/boil over

Hey guys, Overheat /overflow boil over at idle, thermostat new, water pump new 7/16, never heat problem before with the exception the fan would come on after key off, ran for 5-6 min. Now fan issue may be point of interest, will operate with a/c on, but intermittent with a/c off. Thoughts are ECT sensor malfunction... looking for any other possible causes, any ideas?? .

Last edited by nonturbo; 06-08-2017 at 08:53 AM.
Old 06-08-2017, 02:20 PM
Join Date: Jun 2016
Location: San Luis Obispo, CA
Posts: 424

we had a S70 come in onetime with a cheap aftermarket water pump that actually had a broken impeller - otherwise - I'm thinking head gasket
Old 06-08-2017, 09:22 PM
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Thanks for reply ! Yeah, it was after market... all I could afford at the time .
Not getting any unusual noise from there...

Last edited by nonturbo; 06-08-2017 at 09:26 PM.
Old 06-08-2017, 11:34 PM
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Join Date: Jan 2006
Location: SW, WA
Posts: 2,225

Sounds like either a bad water pump, or possibly head gasket. Start it with the cap to the coolant tank off. If you get bubbling or exhaust fumes with the engine running you had a blown head gasket. If not, I would look at the water pump.
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