[ira968]

My temperature indicator hardly ever went above the bottom white line (8 oclock postion) with the OEM thermostat (often slightly below).



When the thermostat failed last week I replaced it with a Stant thermostat that was rated 82C but has a significantly smaller diameter port than the Whale (sp). I believe this smaller port has reduced flow as my temp indicator now stays between the top and bottom white lines at the 9 oclock position. What I have noticed is a big boost in power and pep -- particularly from 2,800 rpm and up. My engine seems to like the slightly higher head temperature. It's a very noticable performance boost and something others may want to consider if their temps run around the first white line position.

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[flash]

what is likely going on is that now your cooling system is working properly, providing more even temperatures



gasoline engines run best at roughly 190-195 degrees of water temp - too cool and the fuel does not atomize as well as it should - too hot and it vaporizes too early, causing the valves to heat up more than they like - this would be roughly 8:30 - 9:00 or pretty much dead between the two white lines, or a little below



this is exactly where mine runs when i am getting into it - it runs cool when i am cruising - not perfect, but better than running at 10:00 when i'm on it

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[gryphon]

Ira, a write-up on replacing the thermostat would be a great addition to Forums.



Tom

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[ira968]

[quote name='gryphon' post='39579' date='Aug 7 2007, 03:25 PM']Ira, a write-up on replacing the thermostat would be a great addition to Forums.



Tom[/quote]





It really is a simple task to change the thermostat. Getting the c-clip out is the only slightly tricky part and a mirror can help here to see the eye of the c-clip that is recessed in the inlet. I will consider posting a step by step procedure and a couple pictures of the process and tools.

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[ira968]

[quote name='flash' post='39566' date='Aug 7 2007, 01:19 PM']what is likely going on is that now your cooling system is working properly, providing more even temperatures



gasoline engines run best at roughly 190-195 degrees of water temp - too cool and the fuel does not atomize as well as it should - too hot and it vaporizes too early, causing the valves to heat up more than they like - this would be roughly 8:30 - 9:00 or pretty much dead between the two white lines, or a little below



this is exactly where mine runs when i am getting into it - it runs cool when i am cruising - not perfect, but better than running at 10:00 when i'm on it[/quote]



I think my cooling system was working fine for many years with the OEM thermostat prior to it sticking closed one day last week. I always had a steady temp. after warmup right around the first white line. It really never moved much regardless of ambient temp or how hard it was run. I can never remember seeing it between the white lines.



If you compare a Stant to the orignal OEM thermostat you will see the port is roughly half the size. I'm not a hydraulics expert but would think this greater restriction would reduce flow and increase engine temps (just like when my thermostat stuck totally closed and the temp went very high)



Anyway, its just an observation I made on my car that the increased temp has resulted in better running.

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[flash]

no worries



slowing the flow can have a positive effect in some situations - or more accurately, too fast of a flow can cause problems - if the water is running too fast, it can't stop to cool off in the radiator - it can be very cool for a long time, and then heat up and never cool off - if it's too slow, you get swinging temps, visible by the guage going up and down - both are bad - on some of the race cars we used to yank the thermostat and stick in a washer - on others we merely drilled a hole in the plate to allow a constant small flow - the idea is to get the coolant up to 190-195 and stay within 5 degrees or so



thermostats frequently fail in gradual steps - it's a copper spring that fatigues over time - you may actually now have a thermostat that opens more than before - it depends on the extension of the spring as much as the diameter of the aperture



the temp of the thermostat you chose is correct - at 180, it should make the engine run at 190-195 - 10-15 over the thermostat is the target



the bottom line is that it seems to be working now and that's great



any chance you got the part number for the stant?

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[xrad]

just replaced my radiator. old one practically fell apart on removal. The hose connectors were cracked, the overflow return nipple fell off cracked at the threads, end cap had a wear groove due to prior accident which bent sheet metal in to it(probably years ago)



Anyway, new one goes in real easily from the top so no need for lift. Replaced some hoses and thermostat, too.



checked t-stat, too. T-stat spring retainer was cracked(explains the weird temp gauge readings..Hot, then cold, then hot). Thermostat retaining clip in a bad spot and I had to make a tool to get the clip out...see pic. Used a long needle nose plier and MAPP gas heated the end which I then bent to the correct angle, and ground the tips to fit in the clip holes. Cold quenched for semi hardness and the tips did not bend when I used it. Replaced clip in different orientation so it would be easier next time. I put in an 80 degree stat.



filled with phosphate free Zerex. Again...because I just did this a month ago. Lots of grey crap in hoses, someone must have used Stop leak or something before I got the car.



thermostat located in aluminum housing into which the BIG end cooling hose connects. (if looking at the engine from front bumper, this is on your left below the power steering reservoir.

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[Cloud9...68]

I feel better about the way my temperature gauge behaves after reading through this thread. Apparently regardless of how hot it gets outside (I say apparently, because obviously the heat of the summer hasn't arrived yet), the needle varies between having its bottom just rest against the top of the 8:00 oclock line, to being just barely off the line. I haven't seen it hit 9:00 oclock since replacing the water pump and thermostat several weeks ago. And running it hard also doesn't seem to make it run any hotter, either. So, it seems to be stable and happy in a fairly tight range. I was getting a little concerned, because it seems to have taken a small step up in operating temperature, which I can't explain, since it started last year, well before the pump and t-stat replacement. But, from the posts in this thread, it seems to be running in a more optimal range than before, so I guess everything's OK.

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[xrad]

since the repair(ambient temp ~70-80), temp runs just above lower white line at idle ...to a little below upper white line before T-stat opens, then drops to 'the middle to slightly higher than the middle' of the two lines if I run harder. Highway cruising, needle a little above lower line.



Never above higher white line.

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[RPM]

If I am running the AC the temp rarely gets to 9 o'clock. With the AC off it will bounce up to nearly 10 in stop and go traffic until the second fan kicks on and then it drops like a rock back to 8:30.



Watching my temp gauge is like a full time occupation. I wish it was not so darned accurate. I've never had a car with a gauge that moved so much.



Of course here in NC the non-AC days are just about over with... until October.

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[Cloud9...68]

At what temperature is the second fan supposed to kick in? I feel like a total dope, but I didn't even realize the two fans came on at different emperatures.

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