Sounds like an option but I don't put my away till about end of november,

and it gets pretty cold here at that time sooo.....I'll put the stock one on and leave it at that for now.

The stock thermostat is less than $10, right? The question you have to ask yourself is, "Is the hassle of replacing it worth the time (if you do it yourself) or the money (if you pay labor costs to have it done). The part that is a pain is draining/refilling the coolant.

i had the exact same problem. solution? the cooling system needs to be purged more. best way i have found is park the car on moderately steep incline and leave it overnight. check/fill the radiator and expansion tank. run it in the morning until the cooling fan has cycled at least once, preferably twice. let it cool off and top off the radiator and expansion tank. turn the car around and point it down the hill, parked overnight. check/fill the radiator expansion tank the next morning. run it through a cooling fan cycle. again, let it cool and fill the radiator and expansion tank. one more time pointed up the hill, and that solved the problem for me. tedious as hell, but it works.

i figured this out totally by accident - my driveway happens to be fairly steep :o after doing my turbo install i thought i did a good job of purging it, but was still getting the cold air at idle. only the above finally fixed it.

ahm

I did that but not overnight, if I still have this problem after putting back the stock thermostat I'll try leaving it overnight.

You don't have to leave it overnight. Letting it cycle through a couple of times and then letting it cool is all you have to do. Just let it cool all the way down.

I have this problem as well. My heater blows cold air until I start moving. Then it seems like it blows hot until I get in it again the following day. I have also had 2 instances where my coolant temp has gotten in the danger area. This has only happened twice since going F/I though so I am not too concerned at the time. When it becomes more prevalent I will likely worry about it.

Something else I have noticed since my Vortech install is that my AC doesnt work right. The AC only blows cold air if I turn the temp knob to the extreme cold position. If I turn it to 1 click past extreme cold, it blows hot air. So there is ONLY 1 click on the entire temp knob where cold air actually blows! Any ideas?

These are not really issues to me as I have learned how to use the AC this way and I have learned that the heat only blows once I start moving. Besides, it hardly gets below 20 degrees here in AL.

This happens when the temperature sensor that is under the steering wheel is unhooked. It is on the panel directly under the steering column on the extreme right side. Get that panel down an I bet the connector is not attached. Hope I helped.

If your stock temp needle is moving this is NOT something to let go. Thats exactly how mine started. Keep in mind that if that stock needle moves its registering a 30degree+ increase in temp. Thats the range before it moves. Once the car crosees around 215-220 it starts to move. That is VERY bad. The correct operating temp for this motor is 195. You need to address your thermostat immediately...

i believe i fixed the proglem, just an air bubble in the line. if i start my car in the morning and it's all the way on C temp. and the car warms up between H and C does that show that my thermostat is working ?

No it does not....the car will warm up to the right level. But after driving a while and going back to idle the car should continue to blow hot air if the heater is on and your needle should not move at all. This is a very serious thing with this car. The heads and block are aluminum and do not take well to overheating. Especially under pressure from F/I. If that temp needle goes above halfway at all I would be worried. When mine started to go it wouldn't do it often but I noticed the fans kick on high more often for a day or two then the needle would start getting higher at idle after driving. Eventually one day it would go straight to the top after 15 minutes of easy driving. Pulled thermostat and it never happened again.

Does the Z have a hard coolant line back by the battery ? The G35 does and we have never had a problem with over heating or heater not working right . We bleed the system thru a cap on that hard line . When its warm , we unscrew that cap and wait for air to come out . Put the cap back on , let it cycle a few times and undo it and wait a couple of minutes to see if air comes out again . It has worked great every time .

My Built engine has about 1,500 miles on it. The first 1,200 miles were babied - hardly over 4,000 rpms, varying speeds, no WOT runs. I did have to bleed the coolant system 5 or 6 times when I first got it back due to the no heat issue in the car. But then it seemed fine after that.

Last week I did a few WOT runs through the gears up to about 6500 RPM. First 2 runs were fine. At a the end of the 3rd run the temp gauge shot up, I shut car down immediately, and car overheated from the overflow/expansion chamber. After car cooled down, the temp gauge was normal but no heat inside the car. We tried to bleed the system more this weekend. Heater was cold at idle but warm air came out at higher RPM's. Took it out for a couple of WOT runs and all seemed OK. On the way back in steady 20mph traffic the needle shot up again! WTF?

I guess we will try changing the T-stat (but it will be a pain due to having to remove the Vortech bracket, etc.). Could it be any thing else besides t-stat?

that **** happen to me in the built integra it makes me not even want to go through this Sh*t again i may jsut slap bolt ons and some rims and call it a day.

subscribing....

That is exactly what my car was doing...T-stat most likely...

Thanks for reply MIA.

I will update after we change out the t-stat next week.

On a built motor I would tend to think it is more a bubbling in the coolant system from excess heat. The air accumulates and collects in the heater core/rear cylinders. The best thing to do and what SGP and others have been doing is running a breather tank to constantly purge the system.

Lets start a wager :D 10 "e-bucks" says t-stat :D

Those with FI and the nismo T-stat, my stock one has been working way better. So, good luck, i know how much a pain in the arse it is.

Sorry MIA I thought he was TT. He's supercharged. T-stat it is. :p