98 S70 fan coming on more than normal

shegarty · Post by **shegarty** » 07 Oct 2024, 11:20

Howdy folks, I've been noticing that my cooling fan is coming on more than normal. At first I assumed that it was because it was a very hot summer here this year, then I noticed that the idle was a bit high when warm. Turns out the throttle cable and spring assembly needed a bit of cleaning and adjusting - warm idle is now right where it should be. However, even in cooler weather now I have noticed that the fan is on when I pull into a parking space after driving around town. Top rad hose is hot and thermostat is relatively new, water pump was changed with last timing service which was within the last year or so and there are no signs of leaks or low coolant. Temp gauge on the dash is just a tad before 3 but this is where it has always been for the last 10 years. I'm thinking that maybe the rad/intercooler/condenser pack is just dirty and not cooling as efficiently? Any other ideas?

Post by **MoVolvos** » 07 Oct 2024, 13:34

shegarty wrote: ↑07 Oct 2024, 11:20 Howdy folks, I've been noticing that my cooling fan is coming on more than normal. At first I assumed that it was because it was a very hot summer here this year, then I noticed that the idle was a bit high when warm. Turns out the throttle cable and spring assembly needed a bit of cleaning and adjusting - warm idle is now right where it should be. However, even in cooler weather now I have noticed that the fan is on when I pull into a parking space after driving around town. Top rad hose is hot and thermostat is relatively new, water pump was changed with last timing service which was within the last year or so and there are no signs of leaks or low coolant. Temp gauge on the dash is just a tad before 3 but this is where it has always been for the last 10 years. I'm thinking that maybe the rad/intercooler/condenser pack is just dirty and not cooling as efficiently? Any other ideas?

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Do a drain and fill and see what's on the bottom of the radiator. Coolant perhaps and age of the radiator. The 98 S70 T5 heater core that cracked had a bit of rust into it when I replaced it. That was 2012 and the car had 230K miles.

To be honest I've haven't done a flush or drain and fill since my 78 Cougar XR7 in late 70's. Back then it was drilled into your head to buy the Prestone Kit where you cut the hose and attached the T so you can use a garden hose to flush after running the cleaner. The last coolant fill was when I replaced the radiator on our 03 Odyssey maybe 5 years ago.
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Post by **abscate** » 08 Oct 2024, 05:30

HarveyBridges wrote: ↑08 Oct 2024, 02:06 Based on your description, it seems like your cooling system is working as intended, but the fan might be turning on more frequently than necessary. This could be due to a few potential factors (my personal opinion): [link removed, user deleted]

Dirty Radiator/Intercooler/Condenser: Over time, these components can accumulate dirt, debris, and insects, which can hinder their ability to dissipate heat effectively. You should consider having the radiator, intercooler, and condenser cleaned or replaced if necessary.

Faulty Temperature Sensor: A malfunctioning temperature sensor could be sending incorrect signals to the cooling system's control module, causing the fan to turn on prematurely. Probably you gotta have the temperature sensor tested and replaced if necessary.

If you're still unable to determine the cause of the excessive fan operation, it might be helpful to consult a mechanic for a professional diagnosis. They can use specialized tools to test components and identify the underlying issue

Crap like this will ruin the internet , if unchecked. The good news, we will check it.

shegarty · Post by **shegarty** » 08 Oct 2024, 07:22

MoVolvos wrote: ↑07 Oct 2024, 13:34 Do a drain and fill and see what's on the bottom of the radiator. Coolant perhaps and age of the radiator. The 98 S70 T5 heater core that cracked had a bit of rust into it when I replaced it. That was 2012 and the car had 230K miles.

I did a flush when I replaced the water pump at the timing service and didn't notice anything. I think I will try and clean the cooling stack and see if that makes any difference

Post by **MoVolvos** » 08 Oct 2024, 09:32

shegarty wrote: ↑08 Oct 2024, 07:22
MoVolvos wrote: ↑07 Oct 2024, 13:34 Do a drain and fill and see what's on the bottom of the radiator. Coolant perhaps and age of the radiator. The 98 S70 T5 heater core that cracked had a bit of rust into it when I replaced it. That was 2012 and the car had 230K miles.
I did a flush when I replaced the water pump at the timing service and didn't notice anything. I think I will try and clean the cooling stack and see if that makes any difference

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Cleaning the cooling stack as in cleaning a potentially dirty AC condenser from blocking air to the radiator?
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Post by **scot850** » 08 Oct 2024, 18:20

Check the ETM, the wiring from it to the connector, the connector and the wiring around it. Check the ETM is measuring the temperature correctly with the resistance values relative to ambient.

Also they the wiring to the fan relay above the radiator for corrosion and bad wiring.

Neil.