What degree thermostat do I use?

[Dreco]

Hello all, question.

What temp thermostat should I use? I've been having some issues with my cooling system. you can see the thread here http://www.classiczcars.com/forums/showthread.php?s=&postid=66115#post66115

I know stock is 195, but since I have a high performance motor, I want to make sure I don't overheat it. On occasion I do take my car to track events. Maybe 195 on the street and 180 when I go to the track?? Need some advice on this.

[Bambikiller240]

I don't know about what's best for your 3.0L, but I've always used a180 for my stock 2.4L

[MikeW]

Forgive me for my ignorance but it doesn't seem like it would make much difference. Presumably your engine won't overheat until it's well above the boiling point of water (212 F). With proper antifreeze your boiling point should be over 250 F. In either case, both thermostats would be wide open at that point and therefore have the same effect on a hot engine. If you're engine wants to overheat at that point it seems like the problem would be elsewhere in the cooling system (radiator, water pump, etc.)

[Brett240]

dreco,

195 is fine for road and track, as long as your engine is holding this temp. the original gauge isnt perfect for telling the temp, if your running track you might want to think about an aftermarket gauge.

just to let you know, i had my car on the dyno running for 3 hours at 210 degrees, this is where it made the most power, when the temp was down from this it lost power and torque, we even ran a 7000RPM pass at 228 degrees for the sake of curiosity( though i wouldnt recommend this ) with no damage, so they can run a little warmer

so if your thermostat is fully open at 195 then this is fine. by the way what radiator are you running? 3.0 plus L engines run notoriously hot, though if your temps are soaring on a track then you have a problem.

[2ManyZs]

I think you will find that the opening and closing of the thermostat does not equate to the exact operating temp of the engine... Since the thermo won't open fully till it's set temp, the engine is likely to run "X" degrees higher than the thermo temp, since the thermo opens slowly, therefore the engine can heat up above the set temp slightly.

For instance, if you run a 180, the engine may run 185-190 at constant RPM, and with a 195 it could run 200 or more. Due to the demands on the engine, the thermo is always fluctuating its opening to try to keep a constant temp, however, if you put a large demand on the engine, it takes the thermo a short time to open after the warmer engine water makes it way through the system.....

I used to run a 160 in the 280 with no fan while racing, and the engine always ran at 180-190 while on the track racing....

I'd suggest either a 180 or a 160... of course, I have seen some thermostats that are 165.. but don't know if there is one that will fit the Z....

[Dreco]

well I do have a 160, along with a 4 row radiator with fan shrowd(sp?) I have heard that this might be to cool for street use, and that running to cold isn't good for your engine either. That's why when I was having a problem with my temp (asuming it was thermostat) I decided to change it to a 195 (being winter and all) Driving my car home from work, with the 195, it felt a little slower than normal. I think I'll put a 180 in it and see how that fares.

[Dreco]

BTW, where does one get one of those digital guns that checks heat temps? After reading 2manyZ's posts, I want to be able to check my engine temp. I've invested too much money in this car to take any chances.

[2ManyZs]

RacerWholesale, Pegasus, or any of the major racing suppliers should have either a probe type pyrometer or the infrared.....Prices of the infrared have come down so much they are now cheaper than what I paid for my probe pyrometer many "moons" ago....

One question I have is, are you running a mechanical temp gauge or is it still the original?

[Dreco]

I'm running the original. WIth the 195 thermostat, the needle is positioned on the right side of the 'M' on the word "TEMP". Hard to tell exactly how hot it's really running. Not sure if this is normal opporating temp. I'm begining to see some new gauges in my Z's future.:classic:

[Brett240]

you really need to know what temp your car is actually running

at.

i i uns at 160 degrees than yes this is to cold for any type of use. though as 2 many said just becouse you have a 160 thermo in doesnt mean that it will run at 160. either way having the thermo fully open at 160 is to early.

having a 195 means that the thermostat will be closed (or mostly) below this temp, so the engine will most likely not get cooler than this. if the engine wants to run hotter than 195 it will regardless of wether you have a 160 or 195.

in other words, a 195 thermo will not cause the engine to overheat easier.

[2ManyZs]

Hehe, I kinda thought you weren't running a mechanical after re-reading your posts..... I'd go with a mechanical...even a cheap mechanical gauge is gonna be more accurate than the original.

I wouldn't do anything until you verify the exact temps you are running....

[Dreco]

having a 195 means that the thermostat will be closed (or mostly) below this temp, so the engine will most likely not get cooler than this. if the engine wants to run hotter than 195 it will regardless of wether you have a 160 or 195.

in other words, a 195 thermo will not cause the engine to overheat easier.

That makes sense. I guess what I need to find out is what's the best, operating temp for my car