easystand pro

W176 a250 50k miles
I was driving home when my serpentine belt snapped, I only noticed when the temp was getting to 120 so I pulled over and noticed it was snapped, after the car was recovered home I fitted a new belt and went for a drive, after 5 minutes the temp gauge inside was shaking around going from 90 to 120 in under 2 seconds then back down to 100 and all over the place. I have no codes logged and have flushed the coolant to see if it was a blocked coolant hose or airlock but now it’s only taking 3 1/2 litres of coolant in so I’m thinking it’s the pump seizing which has caused the belt to snap? But I did check the pulley before replacing the belt and it was fine.
Any ideas what could be the cause? I think I’m going to replace the pump myself which is a big job but want to see if anyone els has any ideas to save me some time and money. I have a new thermostat and coolant sensor I can fit but don’t want to change them if I don’t have too.
Thanks for reading any help much appreciated!

chassis

Can you turn the water pump pulley by hand? 50k miles is a very short time for a serpentine belt to fail. How long have you owned this vehicle and how many miles have you put on it?

easystand pro

I’ve had the car since 2018 at 15k miles and has had a few mods like exhaust intake and map since 20k. The belt didn’t fray it snapped clean with no cracks or visible wear to the rest of the belt which gets me thinking why it did snap! Yes the pump could be turned by a finger. With a new belt on, it is turning fine but now having the issue with the temp reading.

easystand pro

UPDATE. Just in case anyone reads this in the future and has had the same problem, fitted a new water pump and the car is fixed there was no sign that the pump had gone as the pulley was turning fine with no belt on but after changed it the car is sorted