3.2 Thermostat Housing (Warning)

[pgill]

3.2 Owners,

I just watched a video of a XC90 3.2 with a failed Thermostat.

The surprising thing is that the failure mode appears to be non standard.

Common failure mode for 3.2 Thermostat

1. Cracked plastic due to return spring shear force and thermal cycles (Fatigue or Creep rupture is the likely phenomenon)

2. Plastic failure of the O-ring groove at its thinnest section


Mode #1






Failure mode #2

Arrow point at location of the failure, I'll search the internet for the picture of the failed part






New Failure mode




Conclusion

I would need to get a closer look at the actual part to confirm but it appears that the plastic housing has deformed due to heat. Two possible reasons.

1. the coolant leaked out and engine got very hot and this warped the plastic

2. an aftermarket Thermostat was used and it was built with an inferior plastic

Beware of aftermarket parts for components like this.

Here is the video

Thanks

Paul




Recommendation

Get the Thermostat in a Volvo box or Land Rover box.
Don't buy aftermarket.
And change it every 10 years.

[truenorth]

I can confirm that this item is a must replace item for car with more than 10 years of age.

I decided to replace the thermostat in my 2011 XC70 with 206K KM this Summer by first removing the intake manifold, etc. The old part was in good shape when I pulled it out so I decided to set it aside for maybe future spare part use, while installing the new factory unit back, about one hour later, the thermostat spring in the old unit decided to let go and it shot across the room luckily it did not hit me nor my face. Upon closer inspection I saw one of the plastic piece holding the spring base broke off on its own.
My advice for anyone replacing the old thermostat is to be very careful and do not put your face in front the open side of the thermostat as the loaded spring may let go anytime...

The job itself was rather straight forward except for the connector to the MAP sensor seems to break off easily. Once the connector clip is broken, replacing the female connector seem to be the only long term fix. I currently have a short term fix for my broken connector clip, and it is on my to do list for this Summer to replace it... the part number is 30658215

[lntravler]

I replaced mine in august after 22 years and 195k. The plastic support was broken. MPG improves from 22 to 24 after replacement

[pgill]

I can confirm that this item is a must replace item for car with more than 10 years of age.

I decided to replace the thermostat in my 2011 XC70 with 206K KM this Summer by first removing the intake manifold, etc. The old part was in good shape when I pulled it out so I decided to set it aside for maybe future spare part use, while installing the new factory unit back, about one hour later, the thermostat spring in the old unit decided to let go and it shot across the room luckily it did not hit me nor my face................

For my 2008 LR2 the Thermostat broke after removal as you described

For my 2010 S80 it was broken before I got there (I did buy my S80 used and I changed it right away)


I am curious did you use an original part (either Volvo or Land Rover ) or did you go aftermarket. Part of the reason for creating this thread was to identify that the aftermarket housing seems to be less reliable than the original part.


Take care

Paul

PS I plan to replace my Thermostat every 10 years