Thermostat housing

[marlineer]

Hi,

I've been having some overheating problems on my recently acquired Berlinetta and decided to overhaul the whole cooling system. The thermostat housing was badly corroded up so I decided to replace it, however...

There is a small (1/4") diameter pipe sticking out of the base on my old thermostat housing which has a small rubber end blank clamped around it. I assumed that this was for bleeding air. This design of thermostat housing does not appear in the Haynes Cortina manual but does appear in the Granada manual; however it is shown as having a hose attached to it in this manual but makes no reference as to what this hose is or where the other end attaches to. Can anyone enlighten me...do I need this hose and why?

Thanks.

[TVRFan]

Depending upon which engine, some of the Cortina/Granada variants had pressurised overflow bottles, so it might not just be for bleeding air. The V6 2.3 and 2.8 engines had a setup which was almost a 'bypass' arrangement, with a 1/4" pipe connected from top of engine via bottle to heater pipes. You had to be careful to plumb it in the right side of heater, otherwise it would overheat in traffic. Don't know for sure if the Pinto OHC engines had this too, I think the Granny did. No clue about the later engines.

[marlineer]

I should have been more specific about the engine. The donor vehicle is a 1980 Cortina, the engine block ID stamp identifies it as a 1982 unit (2L SOHC) but it has an injector head which I believe only began in '85. So, a bit of a hybrid

[greyV8pete]

On the Pinto engine that is a bleed spigot. As it is on the engine side of the thermostat it is to bleed air out of the cylinder head after refilling a drained system. It has a rubber cap secured by a jubilee clip, which is fitted after all the air is bled out of the system.

Recently I have read on different fb forums recently that some people have a pipe attached to the spigot and would offer the following comments. If the pipe goes directly to an expansion tank with a pressure cap, then it is an interesting way of creating a continuous air bleed. However if there are other pipes connected to the expansion tank then consideration needs to be given to the possibility of non-thermostat controlled coolant circulating in the system.

[marlineer]

Thanks. My car has an expansion tank however it is simply a tube from the filler neck of the radiator which extends down to the bottom of the expansion tank.

[MOC Chair]

The small pipe on the thermostat housing was probably introduced with the Sierra which had a crossflow radiator. I don't think it is necessary with a Cortina version. My present engine has this bleed pipe but I haven't found that it is needed.

[andyf]

The Cortinas didn't have this pipe, to aid with bleeding air out of the system the Turbosport forum recommends drilling a small hole in the thermostat outer to let air out of the system. I've done this and it does seem to work but it does take longer to warm up.

[marlineer]

The Cortinas didn't have this pipe, to aid with bleeding air out of the system the Turbosport forum recommends drilling a small hole in the thermostat outer to let air out of the system. I've done this and it does seem to work but it does take longer to warm up.

Yes, I noticed this variation in design when shopping around for a new housing on ebay. The Cortina housing also has a noticeably longer neck as well although I imagine that they all fit on the same engine block (205) without modification.

[andyf]

I don't think the block changed.

[marlineer]

Have just discovered that a core plug has rotted out, fortunately an easy access one (behind exhaust manifold), however if that's gone the others can't be far behind. Have ordered some brass replacements. Will just have to pray the ones at the gearbox end of the block don't go or it's an engine out job

[romeks44]

Just to put my two pennies to the discussion.
On my pinto the thermostat housing bolts on the head not the engine block. Both the new/old (long/short = cortina/sierra) is compatible with EFI and nonEFI head and both head types are compatible with 202/205 blocks.
Best regards
Roman.