Engine: TDI: Volvo V70 D5252T - Thermostat Housing and Thermostat Sensor

[leerowden]

Hello all,

I've had my V70 off the road for around 3 months (as I was using a 4x4 up here in Scotland for the winter months) and I've just got it back on the road (the best vehicle I've ever owned!). Im just about to do some simple maintenance on it including - Pollen/Air Filter replacement, Oil and Filter change as well as a Coolant system clean, flush and change. After having my V70 for over 2 years now and putting 20,000 miles on the clock, I think this is well over-due!

While I am doing a Coolant change, I figured I may as well change the Thermostat and Temperature Sensor as well (Not sure when this was last done and it'll save me from having to drain the system and do it at a later date).

My only question is where exactly is the Thermostat and Temperature Sensor Housing? I have read many forums that state different answers - Some say it is halfway down the engine block next to the alternator.. I can see that this is where the lower radiator hose goes into and it does look like a housing but there is no Temperature Sensor (that I can see) going there. I have noticed that the upper radiator hose goes into a different housing and there certainly looks to be a Temp Sensor there.. But that housing is rather small and I have read forums stating that the replacement Thermostats are too big for that housing?

Is there any possibility that the Thermostat and Temperature Sensor are located in two different housings? Or will they always be in the same one?

Any help on this would be greatly appreciated and/or anyone that has done this job before?

My Volvo is a 1999 V70 2.5 Diesel XTD - D5252T Engine.


Thank you!
Lee

[Richard_TD]

In your second picture there's a hose running horizontally in the bottom right, beside the dipstick. The thermostat housing is on the end of that.

It's a pig of a job to do and you will lose nearly all your coolant.

I'm not sure where the temperature sender is, it's not something I would change unless it was giving trouble.

With the thermostat being such a palaver I would suggest you only use a genuine replacement.

[petrohl34d]

Originally Posted by Richard_TD

It's a pig of a job to do and you will lose nearly all your coolant.

And if not all the coolant then definately all the skin of your knuckles.

My advice is to try and clear the area of pipes and wires as best you can by cable tying them out of the road as best you can. Still a bitch of a job though.

[Richard_TD]

Originally Posted by petrohl34d

And if not all the coolant then definately all the skin of your knuckles.

I originally had "most of your knuckles and several pints of blood" in my post but I must have taken it out before posting. It's an awfully crowded bit of the engine.

I've taken to wearing thin rubber/nylon gloves like these https://www.toolstation.com/shop/p51069?table=no when working on cars. They greatly reduce knuckle loss etc and keep your hands reasonably clean. They don't tear, wrap themselves around stuff or make your hands sweat like nitrile gloves do, and they are easy to take off and put back on again.

[Martin Cox]

A coolant change is a good idea particularly if you don't know what the stuff in there is. If you use genuine Volvo coolant, then unless you have a leak, you won't have to do it again.

When I had the cylinder head off mine I did give some thought to replacing the thermostat as a preventative measure but it was still inaccessible and since it had given no indication of trouble I elected to leave well alone.

There is temperature sensor is in the elbow connecting the cylinder head to the radiator hose and it's electrical connection is just visible in one of your pictures. However, unless it's giving trouble, I'd leave it alone. It's quite possible there may be more than one temperature sensor.

Martin.

1998 V70 Tdi Auto 223,000 miles