1999 s70 overheating in stop-and-go traffic

kumulipo · Post by **kumulipo** » 08 Jun 2018, 12:30

My new-to-me naturally aspriated 1999 s70 overheats in stop-and-go traffic. I can take heat out of the cooling system by running the heater on full, but its a drag on these warm days. Otherwise, the car stays at nominal heat while driving. Seems to me the problem is in the radiator shroud fan. Can anyone tell me at what coolant temperature its supposed to kick in? Flushing the system while I'm at it for good measure. Thanks!

Post by **FlyingVolvo** » 08 Jun 2018, 13:13

Sounds like your cooling fan is inop. With car on and in park, try turning on the AC and going out to see if the fan kicks in. Could be a bad fan, but more likely just a bad fan relay.

Do not let the needle ever go into the red on these cars. A little bump up from the 3 o'clock position is okay, but anything more and you could quickly be finding yourself with a blown head-gasket.

kumulipo · Post by **kumulipo** » 08 Jun 2018, 14:18

Thanks for the heads up. Will replace the relay with one from the junkyard.

kumulipo · Post by **kumulipo** » 12 Jun 2018, 12:15

Well, the junkyard relay failed to correct the situation. S70 at the shop as this is over my head for now. Thanks!

Post by **scot850** » 12 Jun 2018, 12:23

Could be a failed thermostat, bad ECT (coolant sensor), bad fan motor or an unlucky bad used relay. There is one other issue it could also be bad wiring on the ECT sensor at the connector by the power steering pump.

Hopefully not, but could be worst case the head gasket.

Neil.

kumulipo · Post by **kumulipo** » 12 Jun 2018, 12:25

Thanks for the heads up!