Over Heating

Tedison · Post by **Tedison** » 16 Oct 2021, 03:29

Hi I own a 2010 V70 showing 210k. I have posted before regarding running hot, but decided it would be better to do a clean update in the hope that someone can suggest anything that I've overlooked. I will start by listing the work carried out so far:-

1) Check for combustion gasses in the cooling system carried out. Negative.
2) New Volvo Thermostat fitted.
3) New Volvo temp sensor fitted.
4) Cooling system was cleaned and flushed.
5) New water pump fitted.

Symptoms

If the car is driven at 55-60mph with the A/C switched off the live data shows 105-112 deg C. The car has been driven for 50+ miles like this. Drive faster or switch A/C on, and the temp increases until ‘Engine running hot, Slow down.’ Warning lights up. As the temp increases past 94 deg the cooling fan comes on and increases in speed from 12%-94%. This has been checked and verified. The system does not lose water. The car has been driven approx 1200 miles since the fault appeared. The car heater works. The top hose gets very hot, the bottom hose, luke warm. Engine cooling fan runs at 93% and sounds like a jet engine.

6) New radiator fitted. Back flush (YESTERDAY)
After the new radiator fitted the temp was monitored at 102deg whilst stationary, the garage spent an hour trying to bleed any air from the system. They feel there is possibly still air in the system.
I took the car and drove 10 miles home (55-60mph) monitoring temperature. It rose to 107deg C but cooling fan on live data remained at 0% . 2 miles from home I stopped and switched off the engine for 5 minutes. On restarting the temp was 97 deg then almost immediately dropped to 88deg and the fan showed running at 12%. 100m from home the engine temp started rising again. I have removed the cap from the expansion tank and left over night. I should have scrapped the vehicle when this started but made the mistake of spending money on it.
Today drove the car, thought the problem was solved, after 10 miles temp stable at 89deg 12% cooling fan. Then engine temp cuts loose, climbs to 112deg with 0% cooling fan. Bottom radiator hose is stone cold. Please any thoughts…..

Post by **volvolugnut** » 17 Oct 2021, 10:15

Does the coolant tank cap hold pressure? The tank must pressurize to properly cool.
Can you check top and bottom radiator hoses with contact or non-contact thermometer after a moderate drive?
Can you burp the coolant tank by squeezing the top hose many times?
volvolugnut

Post by **RickHaleParker** » 17 Oct 2021, 20:16

Tedison wrote: ↑16 Oct 2021, 03:29 Bottom radiator hose is stone cold. Please any thoughts…..

Hot engine, cold hose. When you had the Radiator out did you check for a clogged hose? The bottom hose ( lowest point ) is where any heavy gunk will settle. Clearly there is no circulation through the hose otherwise it would heat up.

motormikeyman · Post by **motormikeyman** » 18 Oct 2021, 10:06

It's possible the lower radiator hose is sucking shut but there is probably an air pocket in there somewhere.