One of the first modifications done to my Buick was a drilled 180* thermostat a few months ago. Driving around today in some pretty intense heat and traffic, I noticed that the reported temperature on my scanner varied 20* F, from near 200 in traffic to 179 when finally out on the highway at 60 mph. I was never aware that an engine could vary so much in temperature once it's running. And the temperature will vary quickly, like in 1-2 minutes' time. Also wondering how much is the fluctuations of the sensors and my scanner, and how much is the temperature actually varying.

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2012 Chevrolet Cruze Eco - Current car

1999 Buick LeSabre Custom - Former car

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.

I suspect that the higher temps in traffic are because your fans will not come on till around 200 unless your PCM was reprogramed.

I've noticed the same thing with my car BTW.

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2001 F150 a basic six cyl with 5 speed manual trans.
'66 Piper Cherokee 360 CID , 180 hp, 155 mph @ 2500 rpm, drop in K&N filter.

yeah, those temps are probably legitimate. the reason it varies so quickly is because the thermostat will suddenly open, flooding the engine with cooler antifreeze.

Wouldn't the thermostat be open at all those temperatures I posted in my post above? I know the thermostat is good because I tested it before installation. And the decrease is sudden only when going from dense traffic to clear highway, like when you're at a mall. Otherwise it's pretty gradual as you move onto clearer roads that allow sustained speeds. So I do not believe there is an opening of the thermostat allowing a rush of coolant. Maybe the stock 195* stat would do that, but the 180* that should already be fully open should not.

And no, my fans haven't been reprogrammed to come on at 180*. I almost wish they were.

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2012 Chevrolet Cruze Eco - Current car

1999 Buick LeSabre Custom - Former car

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.

Install a hi-speed fan override.

Your temperature variation may just be a fluke of the conditions, or you didn't pay as much attention before. The thermostat simply opens earlier on initial warmup, decreasing the severity of the initial heatsoak. Unless you're moving air, your low-speed/traffic temps will remain the same.

Depending on ambient air temps, it's POSSIBLE in the summer to cycle temps down in the 180 range.

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Before the ScanGauge I had no way of monitoring engine temperature. My gauge cluster is the linear speedometer and gas gauge, nothing else.

I keep hearing how the thermostat has nothing to do with engine temperature once the engine has been operating long enough to open up said thermostat. Looks as if I'm finally discovering that to be the truth.

And installing an over-ride sounds good. Time to search.

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2012 Chevrolet Cruze Eco - Current car

1999 Buick LeSabre Custom - Former car

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.

ScanGauge??? We don't need no stink'n ScanGauge!!!

Ignorance is bliss!!!
85mph Speedo
195 degree Thermostat
One Cooling Fan
Gas Gauge
and noth'n else
What me worry???!!!

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2006 Salsa Vibe - Auto - Side Curtain Air Bags - ABS - Vehicle Stability Control - Tunes No Moon - Monotone - Preferred Package - Slate Cyper Cloth - Steelie Wheels

2002 Snap Orange Beetle - Auto - Turbo

1991 Dark Garnet Red Oldsmobile 88 - Donated to Science

I always thought this debate was interesting *until* I got a 180 drilled Intense thermostat.

The anti-180 argument always went something like this: "Your engine is going to run at whatever temperature it heats up to and achieves equilibrium with the cooling system -including everything which that entails, such as ambient temperature, fan performance, vehicle speed, radiator size, etc.. . . -opening the thermostat earlier should only give you a brief amount of early cooling before your engine gets to the same temperature that it would if you had a stock (195) thermostat in it."

My actual experience: Most of my driving is highway. At highway speeds, your fans aren't running, but there's plenty of air flowing through your radiator. Under these circumstances, my car runs at 180 degrees. The bottom line is that the cooling system is at least efficient enough to cool the coolant to the temperature at which the thermostat will open and close. Therefore, the car now runs at 180 degrees instead of 195. If your driving is mostly stop and go in traffic, then you will likely get a different result. The fans in a stopped vehicle most likely do not match the cooling performance of the airflow through the radiator at highway speeds.

The next question of interest would be to ask what benefits, if any, are associated with running the engine cooler than stock design. There is likely to be continuing debate on this topic. The most common benefit listed is usually the longevity of the intake manifold gaskets and delaying the self-destruction of the UIM at the EGR stovepipe. There may be continuing debate on that topic, but I think anybody who has experienced intake failure would be interested in modifications that might prevent it.

A typical argument against the 180 thermostat that I hear often is that you might get worse gas mileage. That's possible too. So far I haven't noticed a drop in fuel efficiency.

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And the stock fan settings don't kick in until it gets REALLY hot. Guess that should have been my wakeup call.

Another benefit is the car doesn't fall on its face after several hours of highway travel. I've driven I-81 to I-77 with both the 195 and 180 stats. Lots of hills to keep an engine toasty. The car felt gutless hitting those hills with the 195. With the 180 I had to back off the gas a little bit to hold it in 3rd, even with a full load in the car. Recent observations bear this out as well.

I've seen my best tank to date on the 180 stat. Mileage isn't an issue from what I've seen.

I'd say the pros for it outweigh the cons. For a $7 part, I'm plenty happy. And the cooling system seems more than adequate for what most of us use our cars for.

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2012 Chevrolet Cruze Eco - Current car

1999 Buick LeSabre Custom - Former car

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.

the 180' t-stat is something I'll probably be doing soon, so this is good info to know...

however, i have no idea how to to the override...is there a write up somewhere?

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-Chris
2006 Grand Prix GT
Sport Red Met. - L32 Supercharged, Tint, Leather, Heated/Power Seats, Remote Start/Keyless, Dual Climate Control, 17" wheels, 70k miles. Mods to come.

1997 Bonneville SE *Sold*
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http://users.adelphia.net/~bpaskevich/i ... l_Fans.htm

That's what I've found on the subject. I may end up getting a reprogrammed PCM that kicks the fans on at 180. Likely the easiest solution to a few gripes, among them the fans.

CJ, you might want to flush your cooling system while you're doing the stat. Have to take the stat out to flush it anyhow.

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2012 Chevrolet Cruze Eco - Current car

1999 Buick LeSabre Custom - Former car

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.