Johnz02Z06

I am replacing my water pump and thermostat today. Should I replace the thermostat with a stock 187 degree or a 160. The car is a 2002 Z06 with 83,000 miles. It's a daily driver (20-30 miles a day) in Seattle, Wa. The car often runs in the 215-230 range in the city, light to light traffic and about 215-220 on the highway @ 60-70 MPH cruise

Bill Curlee

Unless you change the coolant fan turn on times/temps, it wont much matter. From what you have explained, it looks like you might need to use the garden hose and back flush the sand out of those radiator fins.

There is also a 1 inch space between the AC Condenser and the radiator. It can get clogged with grass and dirt. Work on getting that cleaned out.

190-220 are perfectly normal temps 230-235 is not out of the norm when in slow traffic.

BC

bob22z06

Bill said it!!!...I myself just picked just up the 160° t stat havent had a time to put it on ...for me seems like the car losing alot of power when it hits past 215° I know the t stat not going to matter that much...will see what happens. ..

Johnz02Z06

Thank you very much Bill.

racebum

it's worth about 2mph, maybe a tad more being at 190deg water and oil and 220deg water and oil

190 and cool i was seeing 115mph, at 220 it was 113, 112.5mph

i tested this just for the hell of it when we were at a weekend track event

runner140*

In South Florida, in the summer, the 90's and mid 90's are a daily thing.
I change my t-stat to a 160 at the beginning of summer and also usually do a coolant system flush. Its a daily driver and gets driven 50 miles a day, seven days a week.

QCVette

Bill has it right.

You said you are running 215-230 city and 215-220 highway. With either the 187 or 160 thermostat they are both open at those temps. The thermostat helps to warm the engine to the opening temperature, but after that it is the cooling system capacity/efficiency that determines what temp it will run at.

The fan turn on temp will have more effect on the temp after warm up than the thermostat (especially for the city).

Also like Bill stated check for the radiator being clean and unobstructed. Usually at highway speeds there is good airflow and the fans frequently are not needed. Since your highway temps are nearly the same as your city temps, it seems like you are not getting good airflow to keep it cool.

Good luck.

aaronc7

I would not do a 160F for a daily driver type car. All it will accomplish is taking the car longer to reach operating temp = more wear on the engine over time. I think stock or 180F tstat would be fine. Like the above posts say, first make sure your cooling system is working properly.

dcandel

Look into buying a "Cool It" from Sac City Corvettes. Simple installation (about 15 minutes). It will allow you to turn on your high speed fan anytime you want if you don't feel comfortable about higher temps in traffic. Also make sure you clean the front of the radiator and condenser as mentioned above.

NukeC5

Anyone that wishes to maintain an emissions legal status must not lower t-stat temps. The coolant needs to be able to heat up quickly, too much time and the car will fail the warm up cycle part of the test. (If you are being 5-gassed). I dont know about this new plug in test they're doing. Anyways, being in cali, I opted to keep the stock t-stat. Car still makes plenty of power with a H/C setup. 430whp/390tq. Its not necessary to change it out. Too many people think it's a requirement.

2003Evo

to answer the main questions..YES a 160deg t-stat will def help to keep the engine running stronger and make power. It has been proven for many years.
A hot engine will wear pre-maturely not a "cool engine"..we talking cool vs hot not COLD vs hot. The only reason vehicles have higher temps t-stat is for emission purposes PERIOD..not because GM thought its best for the car. If your can change it do so, BUT unless you program the fans to adjust to that t-stat, no point on doing the swap.

neutron82

... 160 is just too low in my opinion, I run a 180 in mine with a dewitts radiator, spal fans, and I have a huge intercooler in front of everything and my operating temps are right around 190, maybe slightly more sitting at a light... obviously this is after having the fan settings changed, as stated above if you don't change the fan settings and just install the thermostat all that will do is take the car longer to warm up and your operating temps will still be the same... it hasn't been very hot here yet so I will see how it acts in the summer heat but I don't think it will be much different... somewhere between 180-190 operating temp is about perfect, not too hot and not too cool and it is still enough to evaporate condensation in the crankcase

printmanjackson

the water temp that produces the most power is between 195* and 205* on LS engines

Johnz02Z06

Thank you for all of the input everyone. I went with the stock one. Sounds like the best for a fairly stock daily driver. The water pump change out was not too bad either.

65GGvert

Changing the fan turn on temps won't help your temp on the highway anyway. The fans don't run above 35 mph. You did the right thing. Now try what Bill said about cleaning out your radiator and condenser fins.

danieloneil01

I bought some window screen material from Home Depot and might try to install it under the radiators to keep crap from getting between them. Everytime I remove my air filter it has a ton of leaves stuck to it where it touches the radiator.

warlock007

turn on temps on the highway can be changed as well, I did mine.

I have absolutely no issues with warm up times unless it is winter time in CT. passed emissions with all my mods and 160 stat but now that I am in FL warm up time starts before it is started as i wake up to 70-75 degrees, afternoon 85-90 at this time. The worse part is the crazy stop light times, I just shut off the car and give it the 5-8 minute rest.

The engine needs to be at or above 180 degrees for 1/2 hour to burn all condensation out of the oil, I think thats why tuners aim for 185-195 other than thats the best power temp.

In Wash state, just make sure your cooling system is working correctly.

65GGvert

The fans are designed not to run at highway speeds. They will actually impede air flow through the radiator at speed.

warlock007

according to the 2002 Z06 stock fan tune, fan 1 turns off at 56KMH(34.8 MPH)

cut and paste from stock tune under system/FANS/Parameters

Above this vehicle speed, both fans will be switched off unless above engine coolant temperature turn on thresholds.

G0920 that Fan 1 and Fan 2 will turn off at 145 KMH (90.1 MPH)

so the theory of not designed for highway speeds doesn't necessarily hold true at least for fan 2 according to the stock tune settings. unless I am reading it incorrectly which is possible.