Moss Motors, Ltd

I've got a 77mgb and I replaced the thermostat a while back and since then I've been running a bit cold.  I've had the car for 22 years now, so I'm fairly familar with it and I've never seen the guage run this low. 

 What would happen if I put the thermostat in facing the wrong direction?

 Thanks,

Derrick

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1977 MGB - My First Car, purchased in 1987

I’m not sure as I’ve never done it, but I think that the car would over-heat as the thermostat would not open.  If it didn’t open the coolant would not enter the radiator.

MGAdavid,

Why wouldn't it open?

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill,

I sure that you have a much better take on this than I.  My thinking is that if the thermostat is in backwards/upside down then the copper diaphragm/spring would be on the cold side of the thermostat housing, If you had a 180 stat in the car, don’t you think the coolant in the engine would be almost at the boiling point before the coolant on the radiator side would be hot enough for the thermostat to open. My “cop-out” is to say that at that point most of us would shut down.

If the system is entirely free of air, there would be no "cold side". The cylinder head is the hottest running part of the engine. But you are partially correct. The water immediately below the thermostat is the liquid "fresh" from the heat making area, so it would be hot first. A thermostat installed upside down will open late, but it will eventually open. That's my only point. I DON'T advocate installation of thermostats in an inverted position to get your engine up to temp!

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Let me sum this up:

If the thermostat is installed backwards it would delay the opening of the thermostat but it will eventually open and my car is running colder than it did before the thermostat was changed. 

It seems to me that there is no relationship between the two and I should look elsewhere for why my car is running colder.

 

Any suguestions?

 

 

 

 

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1977 MGB - My First Car, purchased in 1987

I have a 77 b and am just a learner to date.  But,....and this is just a thought,....perhaps your old thermostat was causing your B to run slightly hotter (not sure of the reason for replacement to begin with) and now with a new one, it's running where it should be.  ----or---- the new thermostat is just plain opening earlier than the other.

Although the thermostat does limit the flow of coolant a bit when opened, it does NOT regulate the operating temperature such as a household thermostat might do. All IT  does is allow the engine to warm up before coolant starts to flow. The higher the temperature of the thermostat, the longer it will take before coolant flows.

If you car is running cold, it may not be the thermostat at all. It may be that your mixture of water to antifreeze is off. Water removes heat where antifreeze does not. If you're running a pure water mixture, you'll be removing much more heat from the engine.

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On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"

'68 Sprite 1275
'76 Midget 1500

Maybe this is a good excuse to drain and flush the radiator and start over with a new mix of antifreeze.  I'll let everyone know the results.

 

Thanks,

Derrick

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1977 MGB - My First Car, purchased in 1987

Does the new thermostat have the same temperature rating as the old one?  Perhaps you put one in with a lower rating thereby allowing it to open early resulting in the lower temp????  I've always used a 50/50 mix of water and antifreeze.

Well, this seems a little obvious to me, but maybe somehow the thermostat is stuck open (or missing). I really dont expect this to be the case, but since the issue seems to be concentrated around the possibility that something is wrong with the thermostat, I'd say just open it up again and put in another brand new one.  It looks like moss has them for $5, and I would guess you can get one at the local store as well. I don't like to do