[Guide] Twinspark Thermostat Change - Alfa Romeo Forum
You are currently unregistered, register for more features.    
Thread Tools Search this Thread
(Post Link) post #1 of 1 Old 31-07-14 Thread Starter
Status: Planning summer upgrades
AO Member
AussieAlex's Avatar
Join Date: Feb 2013
Location: Aussie in Sweden
County: Stockholm
Posts: 742
Images: 12
[Guide] Twinspark Thermostat Change

Changed my thermostat today and just thought I would post a few tips that helped make it easier for myself which weren't included in Smaky's TS thermostat change guide;


Firstly I found it highly useful to remove the engine cover (I have a CF3, so plastic cover) as it gave me slightly better access to the top securing bolt as the edges of the cover protrude slightly and I found it was getting slightly in the way of my spanner.

Secondly, I removed the expansion tank cap before disconnecting the bottom radiator hose which drained approx. 3-4L of fluid. After which, I disconnected the hose from the thermostat that leads to the top of the radiator (ie, disconnected the hose leading to the top of the radiator from the thermostat).

I then proceeded to unplug the temp sensor electrical connection and then unbolted the thermostat. Once I undid the two bolts securing the thermostat to the engine block I proceeded to remove the 3 remaining hoses connected to the thermostat.

I found it easier to remove the hoses leading to the expansion tank, towards the firewall and the hose on the underside of the thermostat after unbolting it from the block as it was easier to contort it and get access to the securing clamps on the hose connections.

At this point, once the thermostat was completely removed and the temp sensor screw had been removed from the old unit, I grabbed the garden hose and flushed both the block and the radiator. I did so by firstly placing the garden hose into the side of the engine block where the thermostat would normally be. This flushed all the coolant from the block out through the bottom of the radiator (which was the first hose disconnected). Once the water turned clear for a good minute or two I proceeded to flush the radiator through the top radiator hose which again, flushed the crap in the radiator out through the bottom.

As regular water is obviously 'bad' for the cooling system, I then proceeded to flush the system once again (in the same order) with demineralised water. I put about 3-4L for each flush (block/rad). Then it was time to connect the new unit!

I began by placing the temp sensor screw into the new unit and then bolted the new unit onto the engine block. At this point I placed all the hose connections back onto the new thermostat (REMEMBER TO DO THE BOTTOM RAD HOSE!) and just like Smaky, I replaced the hose fittings for jubilee clips as they are just a million times easier to use. However! Before securing the top radiator hose to the thermostat I filled it with demineralised water (just poured it through the hose into the radiator). I would have got a good ~4L in there before securing the hose onto the thermostat.

Once everything was nicely secured, I filled the expansion tank to the 'max' level with demineralised water and then connected the electrical temp sensor cable to the thermostat unit. I then started the car up after doing some final checks to ensure all hoses were connected with the heater on max heat and full fan. I ran the car until the fans kicked in for a few minutes and the temp hit the 90*C mark on the temp gauge (approx. 10mins).

I left the car to cool down for about 30-40mins until the coolant hoses were warm to touch but not burning hot! At this point, I disconnected the top radiator hose from the thermostat unit and drained another couple litres of fluid to flush any last remnants of the old coolant out of the system (I changed from a green type to a red OAT coolant at the same time so needed to be thorough). Then I reconnected the top radiator hose to the thermostat, filled the expansion tank (which had almost emptied) with the new concentrated coolant (got about 2.5L in so far) and went for a quick drive for 10mins ensuring I kept an eye on the temp gauge.

The results? The car gets up to, and more importantly, stays at temperature perfectly (even on an 8*c night). The coolant will need topping up over the next couple of days and as the system so far is mostly demineralised water, I will be adding the concentrated coolant to top it up without any water as you should need about 4.2L of concentrated coolant for a 50/50 mix for a TS (8.4L coolant in the system) and I have only put in ~2.5L so far.

What colour is the coolant? A beautiful clean red colour so there appears to be no signs of contamination as of yet. So overall I would say this method was a great success to myself and hopefully might be able to help some others out there!

Apologies for the lack of photos, I didn't think to take any at the time but will be more than happy to update with photos as needed if people found it informative and useful

Just thought I would share this as it has a little more info into how I flushed the system etc. compared with Smaky's fantastic guide and just has some methods I found a little easier for myself (like the engine cover coming off).


2000 Alfa 156 Sportwagon 2.0 TS CF3

2002 Alfa GTV 2.0 TS CF3
1983 Porsche 944

Last edited by AussieAlex; 31-07-14 at 15:30.
AussieAlex is offline  

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Alfa GTV & 916 Spider

change , guide , thermostat , twinspark

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