First, what is the part number or how do I explain the cooler thermostat to my local part dealer so I can pick one up tonight. He has a regular one in stock but wasn't sure what the temp on it was. Second, my motor does run a little hot I think. I added some antifreeze because it was a little low and it runs a little better, it has never overheated. What kind of a difference am I going to see with this lower temp thermostat? Thanks.

 

First of all make sure whatever you get that its a failsafe thermostate. Stant DOES NOT MAKE A FAILSAFE (that I know of). A failsafe will have a large spring surrounding the thermostate (its a thermostatic spring). You'll have to pay a little extra (or a lot), but thats whats stock and thats why your engine has never overheated.

So another thing, the stock thermo is 180*F, the performance one is 170*, the problem is that someone on the org tested them (a few different brands) and found that the 170* is opening right at 180*, so this is probably a manufacturers problem, whether or not been fixed, I don't know. Dont expect any serious gains from this, if your lucky 0.5 HP (but nothing if its opening at the same temp).

 

So where can I get one of these "performance" thermostats? Name of a manufacturer or a place where I can get one of these fast would be great.

 

I dont think the problem is the 170* thermostat opening at 180, IIRC Aaron tested it and it opened at 170 (same with his 160 and 150 (I think he found a 150 that works but he had to drill a hole in it). I think the problem is the Radiator and rest of the cooling system is just designed to work at 180*. I'm not entirely sure though, thats just my idea. Anyone want to get a custom radiator and find out for us

 

You gotta be careful running non-standard thermostats - if the engine is too cold you get premature wear (because the oil doesn't get hot enough to form a thin film that keeps the metal bits from touching). If the engine temp is too high, the oil loses viscosity & the piston rings get soft (esp the oil control rings which ultimately leads to lotsa blue smoke).
Engines & their oils are designed to work efficiently at around 180 degrees (+/- 10 degrees) - this is why you don't warm the engine up by letting it idle, it's better for the engine if you start driving straight away (the exception are rotary engines).
You'd only use a "performance" thermostat for track racing, where the internal engine temp would get too hot with the standard thermostat (because the engine is sitting on or close to the redline most of the time & under duress). If it's for daily driving, stick with 172 / 180 degree thermostats.

 

Exactly,
First you mention you "think" your engine was running a little hot (but not over heating) Then you added some coolant (which is always a good thing to have) and it got a little better. Since you've added the coolant exactly how far up does your OEM water temp gauge goes? If it goes no higher than half way up and stays there through out the day then your cooling system is working as designed. Now if it's going higher than half way up then you need to check other components before swaping in a cooler t-stat. (cooling fans, air in cooling system, dirty correded/block coolant passages, and possibly a defective t-stat)

MIKE

 

Thanks for the replies guys. I thought the motor was running better because the exhaust manifolds have been "pinging" and when I first put in the new coolant and drove it around a few times it seemed to have stopped. It was a false alarm though because it pops and pings and stuff every time I drive it still. I'm getting a KS code and possibly running a little lean. Hopefully I will find the problem this week.

 

nismobaron, Nissan suggests to use a 170* F thermo. in a TSB! This is also a way to help deal with "heat soak" issues with the ve engine, although primarily caused by a bad KS sub-harness (and the timming subsequently retarded).

MrGone, Aaron found that they DID NOT open at the desired temp. Thats why he went with a thermo designed for another car, but functioning properly (he chose to go lower at 160*F)

 

Eric, oops, lol. I remember now, it was his gauges he tested and they were right (ie. water started boiling and the gauge read 212* IIRC).

Didn't he at one point try out a 150*F and he had to drill a hole in the middle of it?

 

Its okay dude. I don't remember hearing anything about 150*F, but that sounds a bit low.

 

If that's what they are suggesting, does that mean that when I buy the part from a dealership that it will be a 170 degree thermostat?

 

Hopefully! It actually helps to keep the water temp at about 170*F (based on the specified anti-freeze to water coolant ratio) so expect it to open & close at different temperatures if your coolant is old or not at specified ratio.

eric93se - 170*F sounds right for DOHC Nissans (or quad cam VE max's) - my twin cam NX also specified 170* thermostat (76*C in metric). It would apear many newer aluminum block engines need to run a lower thermostat than those with cast blocks (180*F / 82*C) to counter heat soak.

Caution to anyone fitting a temp thermostat from another car manufacturer - they all have slightly different flow characteristics so you need to be sure that the opening diameter & the plunger depth is the same. Add an air relief valve as necessary (drill a hole, that is) & make sure the air relief is pointing up when fitting. Again, you shouldn't need to run a lower temp thermostat unless you're track racing. If your car's getting too hot, replace with standard & look for other reasons as mentioned previously.

 

Thanks. The one from the dealer was 82* C and I just thought he gave me the wrong temp because it was too low. Celsius-duh. I am not having problems with cooling so I will just leave it alone for a while. I'll keep this in mind though.