This my first time attempting to change my thermostat to a 160. Any tips would be greatly appreciated.

 

Is yours a 90 or 96? Either one make sure you have a gasket, thermostat, and some RTV sealant. Two bolts hold the housing on. Loosen the upper radiator hose and remove, watch for coolent and make sure you catch it. Loosen the bolts and wiggle housing off. Pull out old thermostat and place a rag in the manifold hole and use a wire brush to ramove all old gasket. Once housing and manifold are clean place new stat and use the RTV on both sides of the gasket and replace housing and tighten to specs, don't overtighten the aluminum. Replace radiator hose and I let it sit for a while to cure before starting. That should be all. The 160 is not the best stat to use, just makes it longer for the engine to get up to running temp. Not much if any hp gains. These engines are suppose to get a little hotter than usual. IMO using a 160 just shortens the life of the engine. I have 180 in my LT1 and L98.

 

In a word: DON'T.

RACE ON!!!

 

If you do a 160 thermsotat make sure you have a chip tuned for it, otherwise your car will either take forever, or never go into closed loop..

 

 

Last spring I instaled a 160 and the little switchie thingy so the fan turns on at 160degs. also ( will do/buy/burn a chip one of these days) but so far no problems. This Winter I put the new digi-dash in, but so far ( no days over 60degs. yet) the vette hasn't gone over 190-ish

 

Completely false.

The O2 sensor will go into closed loop at around a coolant temperature of 140F, having a 160 will not cause your car to drop into open loop nor will it prevent a car from going into closed loop any differently.

Chips made for those who want to run a 160 contain timing advances that merely optimize power (and they dont really work), they dont make the car go into closed loop. They could contain changes to the ECM timers, but all the timers go off within 2-3 minutes.

That said, with a 96 in NY, I see no reason to change to a 160 from the stock 180.

 

 

Thank you for all the info. I appreaciate it.

 

For an L98 that IS correct, I know, but for an LT1 I've been told that they go into closed loop at higher temps and do it by coolant temp, not O2 temp / time as an L98 does. Can anyone who burns chips for LT1's verify this? I'd like to know.

Also I've read even on this forum that people have trouble passing emissions (And've been told by GM mechanics the same) if they have a 160F thermostat in a stock LT1, why is that?

 

The LT1 engine are made to run around 230 for a cleaner burn to reduce emissions. Running them with a 160 promotes premature engine wear and decreased heater output in winter. The reverse flow of the LT1 system doesn't allow coolant to flow through the intake manifold. My LT1 stays around 190* while driving and 220+ while at idle. IMO

 

Because it reduces the efficiency of the engine. These were designed to run at a certain temperature, lowering it excessively is not good for them. I wouldn't recommend running an LTx engine below 195. Mine operates at 205 with an EWP, modified fan settings and everything else stock, including the thermostat. I'm quite happy with that.

 

No, both systems wont go into closed loop until several conditions are met and timers are expired. Both have conditions on coolant temperature (timers) and that the O2 must reach 350C (200C heated). Its no different for L98 vs LT in this respect, though timer lengths changed often and they may have changed a coolant threshold a bit in the years. As far as I know, from LT1 Edit, the coolant temp setting is usually at 150F.

But, there is also no logical reason why GM would change the coolant thresholds drastically upwards (say 160-170), if they ever did, because the fuel economy requirements only got stricter as the years go by, and so the longer time spent in open loop would destroy the LT1's gas mileage.

A 160 would only effect emissions if the engine actually stayed at 160.

It does not effect heater output, my car puts out hot air when the coolant goes above 120F.

 

My Fail Safe 180 degree t-stat has been keeping my temps at about 178-189. I still haven't seen over 200 degrees in awhile, except when I'm racing.

When I'm out cruising on the highways, the coolant temps are always at about 175 degrees. On stop-n-go traffic, it reaches about 190 degrees and hovers around there. When the car starts going forward again, it quickly drops back to about 175 degrees, IMO perfect for the car's operation.

 

If your engine is running at 175 with a 180 stat there is a problem somewhere........

BTW my 160 stat will stay in my car......

 

Unless its sticking, it will get up to 180 degrees and drop down a little lower than that once it opens to let coolant through and/or when the fan comes on. My fans were programmed to turn on at 190, and off at 175. Maybe that is the problem.

At least I have the peace of mind that in the event my t-stat fails, it will fail in the open position. Last t-stat I had failed that way and pretty much saved my motor from overheating, despite the 130-140 degree coolant temps on the highway. Normal coolant temps were attained around town with the fans coming on as usual. Oil temp was normal at 180-190 degrees though...

 

For decades cars have run at 170-190 degress with no problems. Granted with F.I. and emission, running hotter means burning cleaner, but IMO running a motor at 220 isnt good for longevity. Im more interested in power, so Ill keep mine running cooler. Not cold, but cooler.

 

Fans are shut off on the highway. You dont have any problems, your stat is just cycling open/closed and temps will stay right around the stat temperature.

 

what you all are missing is metalurgy.

Modern engines are a mixture of metals that expand and contract at differing rates. The op temps established by GM are designed to a) meet emissions and b) maximize the expansion/contraction rates of these divergent metals.

It's one area of the engine I will not mess with... Aluminum and iron do things differently, as such, messing with op temps too much can lead to premature wear, more so than running at 220 ever would.

I am not so comfy saying this in regards to the L98, but I am comfy with this in regards to the LT1.

I run a 100% stock cooling system, using about 70/30 water/coolant ratio and a bottle of Red Line Water Wetter. With the climate controls on in traffic (leaves the fans on) my engine will not go about 198. On a cruise, it's about 194~196.

If I don't have the CC on, the engine goes up to 230, back down to 215 just like it should... with no difference in performance.

The only time cool truely helps is in racing... and this isn't racing... I want durability and longevity... not that extra imaginary 3hp.

Oh, as an aside, NASCAR engines are racing with 100% water in their radiators and 3 or 4 row aluminum radiator, those engines run over 200 all day long... and the only time they get worried is when it goes over about 240. The pressure raises the boiling point. However, they don't have the advantage of EG to raise the BP any higher, and they don't want any EG in there cause it will reduce the heat transfer of the coolant.

We use EG in our cars to keep corrosion down, raise boiling point and lower the freeze point. Race cars don't need that.