gjohnson

I have a 84 and was curious if there is a set temp or approx. temp it would go from open to closed loop. I want to put a 180 thermostat but have read conflicting opinions on doing that. Some say it will stay in open loop and others say its better to run a cooler engine and wont effect the open / closed thing cause its based on when the o2 sensor heats up. Help! Thanks

HlhnEast

Put what ever thermostat you want in your car, its going to run at what ever temp its going to run at which is around 200* or so. If your car is running hot, you need to find out why. A 160* thermo isnt going to change things.

WW7

The car goes into closed loop at around 130 degrees, until that time it runs off presets in the ecm..Only after going into closed loop does the engine start using information from the 02 sensor..Using a 180 stat won't make any difference as far as going into closed loop..Unless you change something in your cooling system to make your car run cooler, It will run at the same temperture no matter what thermostat you use..The only exception may be in very cold weather when the ambient temperture is low enough to pull the coolant temperture down closer to the 180 degree mark...WW
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Tom400CFI

Changing T-stat won't affect open or closed loop operation one whit. That is another piece of LORE that floats around these forums for no good reason.

I ran a 160 stat in my CFI car. It went into close loop at 140, and it ran close to 160 under most conditions. Worked fine, for me, but I did it for specific reasons. There is not meaningful benefit to running a 160 in most circumstances...nor is there a meaningful benefit to running a 180 either. Probably won't matter a bit, which one you choose. Unless you're seeking a 160 for a very specific reason, I'd stick with the stock spec.

gjohnson

Thanks for all the replys guys!

Cliff Harris

According to the data in my EPROM my ECM can go into closed loop mode when the coolant temperature is above 104.4°.

odxr

Seems like a cooler tstat would make the car less likely to preignite{ping} on not so good gas like California regular.+ removing the a/c condensor.Opinion?

WW7

Read the posts above, just changing the stat will "NOT" make the car run cooler in warm weather....All a lower temperture stat will do is open sooner , but the car will still run the same temperture in warm weather because the cars normal running temperture is above the stat temperture... You have to change something in the cooling system, like a bigger or more efficient radiator to get the car to run at a lower temperture...Yes, a lower temperture will sometimes make a car ping less, but just a lower temp thermostat won't do it..I also removed the condenser on my 89 before installing my Dewitts radiator and didn't see a change in my running temperture... WW

DanielRicany

You can change the fan on temp to a lower temp and it will run cooler with the addition of a lower temp thermostat.

vader86

As stated, by itself, the stat will not let you get away with that because the rest of the system is not efficient enough to keep it that cool. It'll still get to the same temps.

But if you programmed the fans to come on lower along with that stat change, then yes it would.

You could also add more timing into the chip if you went that route. The off-the-shelf chips do this.

gjohnson

I grounded out the cooling fan to run all the time. Temps dropped.Didnt like it coming on at 235.Temps now don't go over 200

DanielRicany

Having the fan run all the time is not good. Firstly, you can burn out the fan motor a lot quicker. Secondly, you are probably restricting air flow when cruising on the highway, which would cause the engine to run hotter than normal while cruising in hot weather.

gjohnson

Thanks for the reply but I disagree.The car is not my main vehicle so its driven not so much so burning out the fan is slim.Hwy travel is minimal.Like I said temps do not go over 200 even on Hwy. If I was taking a trip maybe

DanielRicany

Well, you can disagree all you want but there's a reason why they turn the fans on a few seconds and turn them off and another reason why the fans are programmed to not come on over 35 mph.

gjohnson

Sorry but running a cooling fan always will not destroy your motor.No need to reply

DanielRicany

Who said it would destroy your motor?

Tom400CFI

My car won't.

THIS GUYS car won't

Or THIS GENTLEMAN

....as a couple examples. Properly functioning, the cooling system should be overkill fro most driving conditions, and able to drive the coolant temps right down "against the T-stat".

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vader86

Your cars, your situations.

Outside of winter, my 86 would never stay near Stat temps, and the system was OE and there were no mods, radiator clean, etc. Even after cooling system modifications it would not stay there until I went with the DeWitt.

Neither did the 88 when OE.

So you won't convince me its adequate in most driving conditions.

Tom400CFI

IDK why people struggle w/temps. I'm not trying to convince you...rather point out that the blanket statement wasn't accurate, since my car (and others) do precisely what you said couldn't be done.

If your car runs the way you're saying in "regular driving", that means there is little to no margin for heavy loads, high RPM...etc. That would be unacceptable to me, and I'm pretty sure that was unacceptable to the original engineers.

gjohnson

Dropped in the 180 thermostat and drove around today. Blew down the freeway didn't get above 185. Around 60 deg today. I'm happy. Thanks for all the replys