Thanks for the input, guess that I'll reinstall the 180 thermostat.

Hi

Since your car is a 1973 you are definitely past the first years of smog regulations of which started in 1965 with conversions being backdated or mandated . That was in California of course.

The minimum then was 180 degrees Fahrenheit to raise combustion temperatures up and hold them up there in Big block engines. Really lots of pollution made for short term driving in the cities.
The regulations covered the six hole engines as well. These were not fuel injection engines so there was a lot of emissions to clean up no doubt!

By 1978 things got even more stringent nationwide and the imports saw this coming.
My 1978 came with a 92 centigrade thermostat.
That’s 197 degrees so our little red blocks needed to make a jump upwards to keep the imports doors open.

You can see this with the revisions made by Bosch, who had bought the rights to the American Bendix fuel injection systems, that filled the back seat of a car with components.
Bosch in essence, helped propel European cars to selling better against the new gas embargo prices that hit the world.
Yes, smacking us Americans in our pocketbooks swooshed away the land yachts but very slowly as the big three dragged their behinds into the eighties.

I doubt you will find newer imports running less than an 87 degree Centigrade thermostats.
That’s 188.6 degrees Fahrenheit.

You will be better off getting the temperature of you oil up higher too.
Today’s oil additive packages are made to handle it.
A better burn creates less byproducts to be left behind and work down past the piston rings.
Technically oil doesn’t wear out but gets dirty. It’s the detergents in oil and gasoline . The gasoline exchanges quite often but oil keeps the byproducts suspended within.

Before pressurized bearings in engines and detergents or ethyl gasoline the oils non detergent oils caused engines to have very short lives. Running a cold engine is the same step backwards.
You would be doing yourself and anyone behind you a disservice by running @ One Hundred and Sixty degrees of coolant.
Getting up to or even just over 200 degrees of coolant temperature is quite the normal thing with the newer antifreezes ans they are like the oils, built to last longer.

You know my opinions, don’t do it!
Phil

Hi

Since your car is a 1973 you are definitely past the first years of smog regulations of which started in 1965 with conversions being backdated or mandated . That was in California of course.

The minimum then was 180 degrees Fahrenheit to raise combustion temperatures up and hold them up there in Big block engines. Really lots of pollution made for short term driving in the cities.
The regulations covered the six hole engines as well. These were not fuel injection engines so there was a lot of emissions to clean up no doubt!

By 1978 things got even more stringent nationwide and the imports saw this coming.
My 1978 came with a 92 centigrade thermostat.
That’s 197 degrees so our little red blocks needed to make a jump upwards to keep the imports doors open.

You can see this with the revisions made by Bosch, who had bought the rights to the American Bendix fuel injection systems, that filled the back seat of a car with components.
Bosch in essence, helped propel European cars to selling better against the new gas embargo prices that hit the world.
Yes, smacking us Americans in our pocketbooks swooshed away the land yachts but very slowly as the big three dragged their behinds into the eighties.

I doubt you will find newer imports running less than an 87 degree Centigrade thermostats.
That’s 188.6 degrees Fahrenheit.

You will be better off getting the temperature of you oil up higher too.
Today’s oil additive packages are made to handle it.
A better burn creates less byproducts to be left behind and work down past the piston rings.
Technically oil doesn’t wear out but gets dirty. It’s the detergents in oil and gasoline . The gasoline exchanges quite often but oil keeps the byproducts suspended within.

Before pressurized bearings in engines and detergents or ethyl gasoline the oils non detergent oils caused engines to have very short lives. Running a cold engine is the same step backwards.
You would be doing yourself and anyone behind you a disservice by running @ One Hundred and Sixty degrees of coolant.
Getting up to or even just over 200 degrees of coolant temperature is quite the normal thing with the newer antifreezes ans they are like the oils, built to last longer.

You know my opinions, don’t do it!
Phil

If you're using the stock D-jet fuel injection, you should use a 180°F thermostat.

The fuel mixture is adjusted by engine water temperature and a 160°F thermostat will cause the fuel mixture to be richer than required.

Make sure you're using the correct style of thermostat and seal.

I suggest you take a picture of what you've installed in case you need to show it to somebody.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com