Thread: My car surprised me today...

I have been running under the assumption that my car had a 180* thermostat put in by the previous owner, as evidenced by the fact that on the highway I never saw a temperature above 188* unless I was really pushing the engine, and on cold mornings I could turn on the heat and never go above 184*. So I have been contemplating putting a 195 in because that is stock and would give me the best mpg. I had been weighing the pros and cons, having to re-bleed the system and all that. This was the first time I would be opening the cooling system, so bleeding was new to me.

I bit the bullet and went for it, picked up a 195 and a rubber gasket/seal, and a jug of the green stuff. I unbolted the housing and pulled out the old and put in the new, only lost about a cup of coolant, so I opened the bleeder screw, topped off the radiator, and closed the bleeder once it started peeing coolant. I let it warm up and watched the gauge
gp04cluster.jpg(this is an old pic, not from today), she climbed to just under the 203 line sat for a minute and fell back to just over the 194 line.

After this whole operation I picked up the old thermostat, what did I see stamped into the bottom of it? 195. My assumption was wrong, the old stat was simply stuck slightly open.

Did you add "green" to dexcool?

nope. I know better than that. The shop switched it over to green when I had the intake plenum done.

Between replacing the stat, and taking off the studded snows, I expect my gas mileage to start rising, especially when summer blend gets here.

everything ive read on the forums. If running cooler than stock hurts mpgs, then returning to stock must improve mpgs

Originally Posted by LS1GTP

but taking off the studded snow tires will help a lot.

you aint kidding, i noticed a big drop, esp. city when I put them on last fall. Even still, I took a couple road trips on them and got upper 20's for mpg. Funny thing, I took them off while it was snowing outside. I hate the noise they make on the road.

I swapped to a 180* in my comp g and noticed absolutely no difference. I then added an open cone and gas mileage went up because the old air filter was so dirty.

I'm not sure why you bought any coolant. I've swapped t-stats a few times on my car and don't loose any coolant. Just drain from the bottom of the rad into a bucket, when that stops take off the hose where the t-stat is, replace t-stat, put hose back on then pour coolant into overflow tank. I tried the 180 and it only hurt my mpg and no increase in hp so back to 195* for good now.

Originally Posted by tod1d

I'm not sure why you bought any coolant. I've swapped t-stats a few times on my car and don't loose any coolant. Just drain from the bottom of the rad into a bucket, when that stops take off the hose where the t-stat is, replace t-stat, put hose back on then pour coolant into overflow tank.

First timer here, wasnt sure how much coolant spillage to expect. Even still, it cant hurt to have a little extra on hand.

Originally Posted by LS1GTP

Why would you think that running hotter will give you better mpg?

You mean running stock? Engine is happiest ~210*. Dropping down to a 180* tstat makes that a hard number to hit, especially on short trips in the winter. Increased engine wear will absolutely equate to a decrease in efficiency.

It may make a difference for you folks in Canada, but southerner's like myself in Oklahoma make good use of the 180*. Your's warms up and sits around that 210+ mark. Mine warms up and hovers the 176* mark. During the summer I may see it creep up a notch or 2, around the 185-194 mark, but its usually 105+* during the hot parts of summer, so cooler is better then.

I saw snow once this winter, for about 2 days, and less than 3 inches total so it doesn't get very cold and car takes very little time to get up to temp.

I never noticed a difference in MPGs, and won't go back to a stock thermo, runs too hot. Normal hot day stopped in traffic floating around the 220-230* mark is too high for my liking.

TLSheff- Here in Maine, might as well be Canada. The mornings it was -10 to -15F, I sat between the 176 and 185 lines, with the heat going. I only see 210 when im idling anyway. Of course with the new stat we will see how she does this summer. I can picture it running alot closer to the 210 than before.

Also, 220 is nothing to be afraid of.. as long as the needle doesnt camp out there. The fans kick on somewhere between 217 and 228 anyway. In the summer heat mine gets to 221 then falls back to 200.