What is the best thermostat for a 1971 240z . 160 or 180?[/quote]

160* for summer. 180* - 190* for fall/winter.

You can survive without a lot of heat (you're tough) but you have to have a working defroster.

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1970 240Z

160 degree, no question.

The L series engines run hotter than you would think. I'm running the 160 with a 3 row aluminum radiator and running temps are perfect.

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John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

thank you i was thinking about 160 too. Question my temp gauge has a white line almost in the middle is that where the temp should be ?

Not necessarily. It depends on what thermostat you have installed.

The white line in the middle of your 1971 temperature gauge denotes 185*. If your thermostat is a 185* unit and everything is running right, your needle should hang around that center line a lot.

But if you install a 160* thermostat, you can expect your needle to rest slightly lower than that middle mark. "Beating" your Z or long lines of slow traffic on hot days will certainly see the needle rise above the middle mark.

Conversely, if you have a 190* or higher thermostat (popular in Frozentoes, Minnesota), your needle will try to climb up into the top 1/3 of the gauge.

Back when I actually drove my Z during winters, I had to put cardboard in front of the radiator to help it heat up enough to actually defrost the windscreen and heat the car. Today I have a 160* thermostat in it and I have trouble getting the needle out of the lower 1/3 of the gauge, even on hot days.

Remember, water boils at 212*F, but we're using antifreeze which boils at a much hotter temp. Also, your cooling system is pressuriZed and even 4-8 pounds per square inch of pressure will raise the boiling point of any liquid significantly. You can actually drive your car with the needle pretty high up on the gauge without any actual damage. Gaskets, freeZeplugs and radiators (or heater cores) are usually the first things to pop when the L24 overheats. The engine itself is pretty bulletproof.

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1970 240Z

Update working on the car cause its the car i want to take aug.4 . changed the it to 160. at idol she about 170 onthe white. line. or a off the line.by a hair what is the right temp.?

So is 160 to low .. i drove she in the winter with no problems .

The "right temp" is anywhere within the operating range, btwn 120* and 250*. You might want different temps for different times of year. You don't use your heater / defroster much in the summer, so you can use 160F thermostat. Go with that and note where the needle spends most of its time on your gauge. That's "the right temp" for your car, with that thermostat, during this time of year.
You don't want to operate your car before it reaches operating temperature. But once the needle shows movement and touches the 120* mark you can drive it. If it touches the red mark above 250F, you should find a way to cool it down right away. Other than that, you're good to go.

My 1970 is happy btwn 160F - 190F.

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1970 240Z

And keep in mind that early Z gauges are notoriously inaccurate.....

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John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

Drove her this morning and she on the middle winter line .. also feel like it driving smoother.
Frank are you the same Frank that was talking to me about the mufflers on my Z at the last meeting?

If you're Dave, yes!!!

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1970 240Z

Thats me... did you get the pipes? frank im so happy the car is driving the best .. now i could make it aug 5... to the z show.

Getting the pipes next month ~ THANK YOU!!!!

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1970 240Z

In the middle in the morning.........the true test is in the hot afternoon sun. Mine would be like that until it got hot out. Then I got a new 3 row radiator, and all is well, VERY good idea.

Oh yeah ~ right Paul. I forgot to mention that. I have a 4-row copper radiator core too.

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1970 240Z