Thermostat gasket?

[Andy Northface]

Just a quicky,my heater isn't quite as toasty as it used to be so I'm gonna change the 'stat. Has the 'stat housing got a gasket in between the two parts or do you use a liquid gasket?

Thanks Andy.

[Rick Barton]

As I recall, the housing hasn't got a gasket but the thermostat has a rubber seal which goes around the outside edge and does that job. I suggest changing the coolant while you're there (unless you know it's been done recently), that will have an effect on heat transfer as well.

[RXS]

^^^^^ what he said you should get a new rubber o ring with the new stat if you bought it from volvo

[Thanatos]

use a genuine one andy or you will be doing it again in a couple of months

[mattytowel]

Originally Posted by Andy Northface

my heater isn't quite as toasty as it used to be

I'm curious - was there a difference in where the temp gauge on the dash settled?

[Andy Northface]

Originally Posted by mattytowel

I'm curious - was there a difference in where the temp gauge on the dash settled?

Nope,it hasn't moved.Bang on 9 o'clock. It still gets warm ( the heater) but it takes longer to get warmer than it used to.

I will be using a genuine stat.

I changed the coolant in November for the "long life stuff",so I will be poring it back in.Unless it go's all over the street as normal.

[RXS]

drain plug at bottom right hand of the rad 13mm iirc and has an thingy to put a pipe on to it if you need to collect the coolent

[mikealder]

"Plus Gas" or similar for the two bolts and soak them for a couple of days before trying to remove them, make sure you use the correct size torx bit as they are easy to damage.

I wouldn't bother draining the system you will only loose a small amount of coolant, about half a pint came out of my V70 last year when the stat was changed.

Take a good look at how the stat is sat in the groove within the rubber seal, you need to make sure the replacement is the same, if the stat is simply dropped above or below the rubber seal it will leak and not do its job correctly.

As for indicating normal, the gauge will read normal for an engine temperature anywhere between about 70 to 107 Deg C so the gauge isn't accurate to determine the correct operation of the stat. There is a way to check the stat is working correctly using a multimeter set to read Ohms but it's a lot of messing around considering how little a new stat costs - Mike

[Rick Barton]

I thought the test routine was as follows:

Wait for the wife to go out
Put thermostat in a saucepan of water with a thermometer or temperature probe.
Increase temperature
Note the temperature at which the thermostat starts to open
Note the temperature at which the thermostat is fully open
Decrease temperature
Note the temperature at which the thermostat starts to close
Note the temperature at which the thermostat is fully closed.
Clean, dry and put away the saucepan
Look in mirror to practice not looking guilty
Compare your data to the operating parameters for your thermostat.

[capt jack]

Originally Posted by Rick Barton

I thought the test routine was as follows:

Wait for the wife to go out
Put thermostat in a saucepan of water with a thermometer or temperature probe.
Increase temperature
Note the temperature at which the thermostat starts to open
Note the temperature at which the thermostat is fully open
Decrease temperature
Note the temperature at which the thermostat starts to close
Note the temperature at which the thermostat is fully closed.
Clean, dry and put away the saucepan
Look in mirror to practice not looking guilty
Compare your data to the operating parameters for your thermostat.

A good suggestion but flawed in one vital area:

Trying not to look guilty is guaranteed to make you look - well - guilty! The cost of the chocolates/flowers/new dress etc will be a lot more than the cost of a new 'stat. In the long run, it'll be cheaper and easier to change the 'stat.

And there's no need to drain anything - you only spill a bit of coolant - just make sure the engine is cold before you start, and that the Torx bolts have been well lubricated for a day or two beforehand. Oh and jam some rags etc around the 'stat housing. When you drop one of the bolts you'll be glad you did!

Cheers

Jack