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Discussion Starter · #1 ·
Hi,

I have a '72 GT 1300 Junior with screw-in type thermostat. I decided to switch to drop-in thermostat, so i purchased a new intake manifold but i was wrong and i purchased an intake manifold for the in-housing thermostat. The question is the following. The drop-in thermostat opens at 79 Celsius degree, like the screw-in type, but the in housing type opens at 83 Celsius degree. It is a problem for my engine? I haven't electric radiator fan. Thanks for answering.
 

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105 Alfas do not suffer from overheating when all is in good order - clean radiator, mechanical fan and shroud in place. I wouldn't worry if the engine runs few degrees hotter as a result of the thermostat. Especially if your car is still running the 1300 engine, it has less heat to dispose of - and the only cooling part that is different from a 2000 is the narrower fan blade.

The one time one of my Alfas started running a little hot in traffic, I found out the shroud was hiding the fact that most of the fins had rotted out of the radiator!
 

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How does an "in housing" thermostat differ from a "drop in"? I get the difference between "screw in" and "drop in", but "in housing" has me puzzled. Don't you need to change water pumps to get one with a port for the bypass hose when converting to a later-style manifold?
 

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I think he got a manifold from a 1980s car with this type of thermostat (thanks to Classic Alfa for the photo):
1665590

On the European market, Alfa sold cars with Webers well into the 1980s. And most likely they increased the thermostat rating to gain 0,0001% in thermal efficiency.
Still, would that manifold preclude using a drop-in thermostat given the proper housing?
Or is there another option to cut the legs that hold the thermostat in this housing, and then just use it to hold a drop-in thermostat? That has been done often on GTV6s.
 

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Discussion Starter · #5 ·
105 Alfas do not suffer from overheating when all is in good order - clean radiator, mechanical fan and shroud in place. I wouldn't worry if the engine runs few degrees hotter as a result of the thermostat. Especially if your car is still running the 1300 engine, it has less heat to dispose of - and the only cooling part that is different from a 2000 is the narrower fan blade.

The one time one of my Alfas started running a little hot in traffic, I found out the shroud was hiding the fact that most of the fins had rotted out of the radiator!
Hi, thanks for reply.
I have the 1.6 lt engine insted the 1.3, but if i don't remember wrong, the cooling system is the same. Same radiator and fan. I made re-cored the radiator so it is new. I install a new water pump and obviously the fan shroud is installed so i think i won't have any problems.
 

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Discussion Starter · #6 ·
How does an "in housing" thermostat differ from a "drop in"? I get the difference between "screw in" and "drop in", but "in housing" has me puzzled. Don't you need to change water pumps to get one with a port for the bypass hose when converting to a later-style manifold?
Yes, for switching to a drop in style thermostat is also necessary to change the water pump and install a 3 way pump, like i do it. For the in-housing thermostat type Yvesmontreal has already answer to you.
 

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Discussion Starter · #7 ·
I think he got a manifold from a 1980s car with this type of thermostat (thanks to Classic Alfa for the photo):
View attachment 1665590
On the European market, Alfa sold cars with Webers well into the 1980s. And most likely they increased the thermostat rating to gain 0,0001% in thermal efficiency.
Still, would that manifold preclude using a drop-in thermostat given the proper housing?
Or is there another option to cut the legs that hold the thermostat in this housing, and then just use it to hold a drop-in thermostat? That has been done often on GTV6s.
Yes, i got this thermostat type.
Unfortunately the manifold doesn't permit the installation of the drop in style thermostat. It doesn't has the legs to fit the drop in style. It has a completely flat surface for better match with the rubber gasket of the in-housing thermostat. I also think that maybe i can cut the legs for the drop in thermostat by someone, but before i'll try it the in-housing thermostat for watching the engine temperature.
 

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In this type of housing , the thermostat is actually clipped in place and removable. Alfa used to sell replacement thermostats without the housing. Today, the aftermarket provides housing assemblies and no choice of opening temperature are offered.

One of the vendors I checked states that the thermostats he sells for Bosch Spiders are rated 180 degrees F = 82C. Close enough.
 

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In this type of housing , the thermostat is actually clipped in place and removable. Alfa used to sell replacement thermostats without the housing. Today, the aftermarket provides housing assemblies and no choice of opening temperature are offered.

One of the vendors I checked states that the thermostats he sells for Bosch Spiders are rated 180 degrees F = 82C. Close enough.
I can't quiet remember without having one in my hand but I think you can unclip that style of thermostat and grind down the pin a little. This reduces the spring pressure and effectively makes it a cooler thermostat. Don't hold me to that.
 

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Discussion Starter · #10 ·
I can't quiet remember without having one in my hand but I think you can unclip that style of thermostat and grind down the pin a little. This reduces the spring pressure and effectively makes it a cooler thermostat. Don't hold me to that.
That's should be a good idea. I've yet install the thermostat so i can't verify it. Maybe if the temperature will be too high I'll check it. Thanks for advice.
 

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Discussion Starter · #12 ·
Here is a thread about an apparently similar 164 thermostat. It also seems these thermostats are not all built the same. I would just leave it alone and see.
Thanks for the thread links. These thermostat aren't the same but how you said they are very similar. Right now i can't start the engine so i can't check if the temp is too high. If so, I'll remove the thermostat and check if is possible to remove it from the housing to modify the pin.
 

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Thanks for the thread links. These thermostat aren't the same but how you said they are very similar. Right now i can't start the engine so i can't check if the temp is too high. If so, I'll remove the thermostat and check if is possible to remove it from the housing to modify the pin.
Just to be clear I wasn't suggesting you modify it without good reason, just that it's an option given that style of aftermarket thermostat doesn't come in different temp ranges anymore.
 

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This is the one your looking for. If your intake does not have the grove cut in it for a regular thermostat. The Bosch one will not work.


If your has the groove cut in it this would be the thermostat you want to use.

 
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