Engine Temperature Increase after Water Pump, Thermostat and Coolant replacement

[abscate]

Its my old guy evolution to get good access to stuff rather than play tricks to get to components

When you are in the trade , you can practice a trick 50 times and nail it.

We aren’t in the trade and , just like the example above, can easily Fubar the hack.

[cn90]

As others have commented previously, it's not very difficult to just move the PS pump aside and do the whole thermostat job with the proper part. Making mountains out of molehills on this one.

Not true,

So "...do the whole thermostat job with the proper part..."

You need to define "proper", which in Volvo's book is making money.

Volvo overkilled this part in the P2. You do NOT need to replace the housings. All you need is a thermostat, maybe (maybe) ECT. A Thermostat for P80 (such as 1998 S70) is $14-$15.

Removing the serp belt requires thin tool to move the tensioner. Then move the PS Pump, then re-installing the belt in the tight compartment without a 2nd person to help is not my favorite.

Swapping only the tstat and ECT as I mentioned above is very very easy. No messing around with serp belt or PS Pump.

This is one part of Volvo engineering that is worse in P2 cars. Changing the tstat in the P80 cars was very easy, minus the infamous Torx bolts!

[XC70Rider]

Six months after reinstalling the OEM thermostat housing I started loosing coolant. Being a very slow leak I filled up the reservoir 3 times since December 2019. It was ~800 mile intervals. Green coolant was dried up surrounding the thermostat gasket. Never saw any fluid dripping. I replaced the thermostat housing gasket last summer but as stated earlier you cannot purchase the thermostat valve nor it's gasket separately. A whole new unit needs to purchased to get either one.

I got the Wahler 31293698 Thermostat from a 3rd party distributor on Amazon for $91 total. Came in a Borg Warner box because they bought out Whaler. Removing the belt and PS pump is getting easier each time so I installed the whole new unit including the housing.

For future reference the OEM thermostat valve gasket starting leaking at 136,400 miles.

[oragex]

You can also clean well the surfaces and use RTV for coolant. The trick is to put just enough so the bead doesn't fall inside the housing, and to follow the instructions for the curing https://www.permatex.com/products/gaske ... ne-gasket/

[XC70Rider]

You can also clean well the surfaces and use RTV for coolant. The trick is to put just enough so the bead doesn't fall inside the housing, and to follow the instructions for the curing https://www.permatex.com/products/gaske ... ne-gasket/

Using RTV did cross my mind but decided to get a new whole unit. I'm keeping the OEM unit cause only defect is the thermostat gasket. May come to use in the future if needed.