Thermostat - Alfa Romeo Forum
You are currently unregistered, register for more features.    
Thread Tools Search this Thread
Status: - Update
Posts: n/a

I know there's been loads of postings about thermostats etc, I'm thinking of changing mine as the temp is running at 70 deg and the fuel consuption is rubbish as well as running a little rough. The question is do you have to drain the system to fit a new thermostat or can you just bolt on the new one in place. If you have to drain the system where from? how do you fill it up so as not to get any air locks?

Sponsored Links
Status: - Update
Posts: n/a
In theory, you drain the system, however it is easier and just as effective to simply unbolt the thermostat and let any coolant that wants to escape. (Only do this when the coolant is cold) When the old one is off, clean and dry up the mating sufaces you're going to use and make sure any old gasket is gone.

Then bolt up the new one. Either use a proper gasket or something like Hermatite red gasket compound which does a fine job.

Check all is done up tight afterwards.

To re-fill the system, simply fill the header tank up and wait for any bubble to stop. Squeezing the rad pipes helps.

When its stopped bubbling, run the engine with the header tank cap off and the heater on full. Also a good oportunity to check your new thermostat. The level will drop. Keep it topped up to the line. When the cooling fan has kicked in a few times and the heater is belting hot air into the car its all done. Replace the header tank cap.

When cool top up again and keep an eye on the level for a week or so. Movement of the car may well move some air bubbles.

Good luck.

Ralf S.
Status: - Update
Posts: n/a
Yep, I just unbolted the hose on the 'stat and let the coolant run out as much as it wanted.

The missus wasn't too impressed mind you. It completely soaked the living room carpet.

If you do yours outdoors you should be okay though.

When you scrape off the old gasket, dont use too pointy a screwdriver or you may put a gouge in the mating surface. Use a new gasket and some blue sealing compound (Solvol Blue Hylomar or Halfords own brand have always seen me alright).

Ralf S.

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Alfa 155


Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

For the best viewing experience please update your browser to Google Chrome