Slow2.8

if i get a new thermostat, will my fan still come on? even thought it's not the same temp?

TomP

Yep, the electric fan is controlled by the fan switch- that's in the rear of the passenger side head, with a single green wire going to it. (You'll have to crane your neck or use a mirror to see it, it's almost against the firewall.) You can replace the fan switch to get the fan to come on lower. But remember the fan really only comes on when you're stopped in traffic, when no airflow is coming over the radiator. The stock fan switch kicks the fan on at 230 degrees, regardless of the thermostat.

82-T/A [Work]

GM puts 195 degree thermostats in their cars (from the 80s) stock because it helps emissions.. the block runs hotter, and helps the catalytic converter burn more efficiently. Forunately enough, modern day catalytic converters are much more efficient than those BRICK converters that the 3rd gens originally came with.

In my opinion, 180 degrees is the coolest thermostat you should run in your car. They do sell 165 thermostats.. but those will make your car run too cool. It MAY affect your motor and it will run in CLOSED loop all the time, but that's the least of your problems. The BIG problem with running a 165 thermostat is that your engine won't be able to reach it's OPTIMUM operating temperature. 165 degrees is FAR too cool for the engine to be running it.

When a motor has heated up, the pistons, the connecting rods, and the crank haven't expanded to "efficient operating level". When you run the motor at that cooler than normal level.. over time it can cause premature engine wear.. ESPECIALLY in the rings. Sure.. you DO get an EVER SO SLIGHT performance increase (not even noticable at a dragstrip or dyno) but the tradeoffs for engine efficiency, fuel economy and engine wear make it not worth it.

Get a 180, and be happy.

What you CAN do.. to assure that your car RUNS at that operating temperature and never higher is to get a "Low Temp Fan Switch".

Todd

LT1guy

iTrader: (1)

I beg to differ. Just because your car has a 160 thermostat doesn't mean it will run at 160...just that the thermostat will open at that point. Most GM cars I have seen (3rd gens both V8and V6, 4th gen LT1s, Buick GNs, etc) will run around 180-185 with a 160 thermostat and a fan switch or chip to turn the fans on sooner. This to me is optimal, though I wouldn't recommend going that cool in a colder climate. The car should stay in closed loop most of the time..I have never had one stay in open loop because of a thermostat being too cool. Bottom breathers like our F-bodies need all the help they can get cooling wise. A 180 thermostat would make the car run in the 190-200 range all the time, hotter in traffic on a hot day , which to me is too hot.

As far as wear is concerned...most wear is at startup, when NEITHER thermostat would be open. Just like the hp gain, I doubt the wear is measurably higher. Use synthetic oil if you're worried about the wear. I have seen over 150k miles on a turbocharged Buick V6, that had a 160 thermostat from the time it was new, and it didn't use a drop of oil. That at 19lbs boost.

82-T/A [Work]

This is the difference though, specifically we are talking about the GM V6/60.
The 80s V6/60 motor has a WEAK bottom end. I've rebuilt several of these V6s, and I can say that these
engines run VERY cool stock. The V6/60 is one of the only motors that I've EVER seen in my life.. that
you could run the motor, and have it stay at NORMAL operating temperature in 80 degree weather, WITHOUT
the fan ever comming on, and it will NEVER overheat.

The 2.8 in my 87 Fiero, I could start the car up, let it warm up...
I could let it sit there for however long I wanted, the fan never came on, and the car would run at a
consistant ~185 degrees with the 180 degree thermostat. And the cooling in the Fiero is FAR worse than
that of a 3rd gen f-body... the Fiero has a radiator in the front of hte car, with a motor CRAMPED in
the rear (forward of teh trunk).



So.. especially in THIS motor... I strongly disagree with using a 165 degree thermostat.. for longevity,
fuel economy, and efficiency purposes. Take it or leave it....

TomP

I wouldn't say the 2.8 V6 has a weak bottom end; I went through this recently with AFrikinGoodTime (see message about "cam and rear gear replacement"). It might be weaker than other engines, but it's not weak. Unless I've got a hell of a rare-version of a strong 237,000 mile 2.8!

I run the 160 thermostat in the summer, and the 195 in the winter- otherwise, I'd freeze my *** off. I see the same thing with my 160 that LT1guy has- the car runs around 180 degrees, and that's with an aftermarket mechanical gauge, not a factory gauge.

As far as fuel economy/mileage, you could get into that debate with any aftermarket modification. I don't notice any change in the summer in my gas mileage or fuel economy. In NJ winters, yeah, because the car stays in open loop, and never warms up!!

And again, like the TB bypass mod, this is mainly a street modification, not a track/dyno mod. At the track or dyno, you wait for your motor to cool down, then you floor it to WOT when you reach the tree. That's more engine wear than a 160 thermo would ever cause!

But like you said, this is an eternal debate, the V8 guys argue for weeks over this same topic.