V8 overheating engine 2010 180K km [Fan electronic Module Faulty] Topic is solved

martinhamel · Post by **martinhamel** » 25 Sep 2019, 09:59

Hi to all, I have a S80 V8 with 180K km on it. I faced for the first time of my life driver an overheating engine, I really taking care of my car yearly.
1- So the coolant was completely flushed 2 years ago,
2- changed the thermostat last week, but still overheating this morning.
3- I will change my water pump is the next step, any other ways to know if I am on the right path ?

The symptom I faced; of course, the light (red triangle) came off in my dash, and when I was using my air conditioning I got suddenly steam into my car.....my windshield came foggy....the transmission had trouble to go over the 3rd gear (tried manually and did not want to switch the 3rd.....when I came out the traffic jam, came back ok, no overheating, triangle light came on until I arrived at my job.

any help is welcome.tks to all

martinhamel · Post by **martinhamel** » 25 Sep 2019, 11:37

Note that I have good heating air system into my car with or without AC, so the inside condenser seems ok and not blocked. No sign of coolant into the car cabin and no leak under the car. No oil presence into coolant, coolant at the right level too. This morning when I came out of the traffic jam and running at 110km the engine came into normal temp with the high flow of air.......

Post by **jimmy57** » 25 Sep 2019, 11:53

Water pump is WAY down the list and would be huge waste. The water pump would only fail if you had a cooling system with SEVERE corrosion with rust and seriously murky coolant. The radiator and heater cores would rot through and leak before the impeller in water pump corroded away so that it diminishes pumping capacity. Start with fan operation since the thermostat has been addressed. If you turn on a/c and let engine idle you should have an audible or even loud fan noise within a minute. If not then the cooling fans are suspect. The controller for the electric fans is a known failure point.

martinhamel · Post by **martinhamel** » 25 Sep 2019, 12:08

thank you Jimmy57, the fans (2) are working great when opening AC only with their 2 variable speeds. There are 2 little plastic pipes attached to the coolant expansion reservoir (overflow tank) we can see there is little flow of coolant into those pipes, but very low pressure, I know I have a strange noise (high frequency) since last year near the water or the power steering. If I press the major rubber tube (coolant) I can't feel high flow.....liquid is there for sure, when hot I can feel the pressure too, but I can't guarantee there is a flow.......too hot..Lastly there is a good pressure into the tank (so cap retain pressure)...tks again Jimmy57

martinhamel · Post by **martinhamel** » 25 Sep 2019, 12:55

My question Jimmy57, the electronic box attached to the radiator, will it work with AC only. Because the Fans are not working UNLESS you are turning on the AC. This morning when I came to work, my AC was working, so theoretically fans were working too. I was jammed, but at the moment I drive to 110km.........everything came normal.....

Post by **jimmy57** » 25 Sep 2019, 22:27

Thanks for the additional info, the cooling fan controller is something I have replaced several of on S80 and the related P3 models for overheating. That is odd. If the fans can be run by ECM for a/c pressure and the ECM is signalling the over temp warning then you may have a failed water pump. I have yet to replace a V8 water pump. Trying to detect coolant flow is hard to do and those small lines to coolant tank have little flow, they serve to purge air if ever it was low and got refilled. What I can't answer, owing to never having replaced one, is if these pumps have plastic impellers. There have been VW/Audi and some others that used plastic impellers on their water pumps and they can crack and slip on the shaft. Removal and inspection is the only sure way to check that. Maybe someoen else will answer that question if they have a V8 S80 or XC90 and have changed their pump.

martinhamel · Post by **martinhamel** » 26 Sep 2019, 06:16

Thank you Jimmy57 again...........I will change the module anyway, for the low part cost it worth the spend. When I did arrive at my home yesterday the red warning was on, and..... the fans were not working even if I was driving with AC.....I will even change all relays just in case I have many on the side..... will repost the result........ Again thank U very appreciated

pbierre · Post by **pbierre** » 30 Sep 2019, 17:42

Have you looked at the condition of the radiator fins? The Volvo P3 radiator has very delicate, aluminum fins...they bend flat with little force. I had about 50% of mine flattened on a used 2013 XC70 I bought. I had to open up these fins to airflow, or else coolant on the verge of boilover in summer CA desert. It looked like someone tried to pressure wash the radiator face at a car wash...bad idea.

What's your coolant temp? Mine was 99C before, 88C after. Got it back to normal operating temp. by restoring radiator airflow.

martinhamel · Post by **martinhamel** » 11 Oct 2019, 08:33

Finally it was the Fan electronic module only 1 speed over 3 was working and it was the lowest one (27%) I used my DICE, the fins are ok pbierre I really take care of my car...........pressure washer are bad idea for a radiator for sure........I was my car by hands

Post by **abscate** » 16 Oct 2019, 08:32

Merci bcp, Martin.

J'ecris la solution dans le titre, pardonnez-moi pour mon pauvre Paris francais