Overheating over 50mph

[Volvo and VW Guy]

Hi, I have a Volvo XC90 D5 2009. I have recently had the cam belt changed and was told the water pump was changed at the same time. Ever since it overheats above 50mph. I have since changed the thermostat, put a radiator flush through it and changed the water refill cap. It has been back to my mechanic twice and he suggested the water cap after doing a pressure test that passed.
Also if I drive a 10mile town based distance, when I stop it sounds like I’ve parked a hover craft. The temp gauge sits at normal.
It also appears to go into the red on the temp guard when going up hill. Then when at the top of the hill and driving around 30-50mph, the temp drops back down.
Using an app and a ODBC tester, 89deg C up to 120 deg C after an incline. Then drop back to 95 ish when at the top of that incline.
It was not doing it before the Cambelt change, but my mechanic does not know why that would have caused the issue and has no idea on how to fix.

I have had the issue for a couple of months now and would really appreciate and advice or help… Please… with cherries on top….

[Simmy]

Possibly a cheapo water pump was fitted iv seen plastic impellors fall off spurious quality water pumps .always use volvo quality asin water pumps or any thing can happen .

[Lancee]

Was a Volvo original water pump fitted ?
Consensus seems to be that Volvo pumps are highly robust so it's unlikely it needed changing ?
If not a Volvo replacement pump, that would be my first thing, change it.

[Volvo and VW Guy]

I’ll have to ask the mechanic and see what they say. Do you think the pump in not efficient at high speed, but ok at low speed?

[Tannaton]

I'd be suspecting the water pump too... generally Volvo pumps last the life of the engine, though there are some exceptions. I'd say 4 out of 5 water pump failures on D5 engines are where the factory pump has been changed for a pattern part in inferior build quality. Belts and braces would be to change the pump at cambelt time for another Volvo one, but second best is leave it alone....

[Kev0607]

I can confirm from personal experience that cheap pumps don’t last.

On my Dad’s V70, the water pump exploded and de-railed the cam belt. The engine was very nearly totalled.

The car was towed to a Volvo Specialist who looked at the old pump and it turns out it wasn’t a genuine one. Expensive lesson. New timing belt required as well as the new water pump and a new timing belt protective cover.

Previous owner skimped on cheap parts. Luckily the cam belt hung on by a few teeth, otherwise it would have been another story. For reference, this happened whilst the car was stationary in a supermarket car park. I suspect if it was actually moving at speed, it would have been another story.

Go genuine.

[Clan]

Originally Posted by Tannaton

I'd be suspecting the water pump too... generally Volvo pumps last the life of the engine, though there are some exceptions. I'd say 4 out of 5 water pump failures on D5 engines are where the factory pump has been changed for a pattern part in inferior build quality. Belts and braces would be to change the pump at cambelt time for another Volvo one, but second best is leave it alone....

100% true in my daily experiences working on them on a professional basis for decades. Anyone who takes a perfectly good volvo water pump off and puts a non genuine waterpump on a volvo is a fool.