# Overheating



## Tayiler (May 3, 2017)

So recently i had to replace my thermostat, it was faulty, and it appeared to fix my glitchy therm, however, now my car is overheating very bad, my heat doesn't work, and my rpms at idle are at around 1200 rather than 800.. I bled the air from the coolant with the cap off twice, for about 20 minutes each time... what could be the problem? I cant figure it out, and it's very financially burdening throwing pieces at it... all help is appreciated


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## RJ64 (Jul 23, 2017)

If you had heat before, and now you don't, your coolant is low. Are you sure the thermostat is facing the correct way? I don't have a service manual for your year vehicle, but search around on this forum to find info on that. And how to bleed the air out properly.


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## rogoman (Dec 16, 2004)

Tayiler said:


> So recently i had to replace my thermostat, it was faulty, and it appeared to fix my glitchy therm, however, now my car is overheating very bad, my heat doesn't work, and my rpms at idle are at around 1200 rather than 800.. I bled the air from the coolant with the cap off twice, for about 20 minutes each time... what could be the problem? I cant figure it out, and it's very financially burdening throwing pieces at it... all help is appreciated


Hopefully you installed an OEM thermostat purchased from a nissan dealer. Aftermarket thermostats such as a Stant many times cause problems. When installing a new thermostat, make sure the "jiggle" valve on the thermostat body is facing up. 

Your best bet may be to drain down the coolant and start all over again with the filling of the coolant.
Here's how I do it:
1 - drain coolant
2 - open the air bleeder screw
3 - set the heater temperature control on the dash to maximum
4 - jacking up front of car as high as possible which helps to purge air pockets
5 - fill system until coolant starts coming out the bleeder hole
6 - close bleeder screw (not too tight; screw is easy to break off)
7 - continue filling until coolant is at the bottom of the filler neck
8 - do not put cap on the radiator
9 - start engine; as coolant starts to warm up, you may see a few air bubbles
10 - squeeze the hoses by hand to free up possible air pockets
11 - put cap on radiator and continue running engine until fully warmed up
12 - after shutting off engine, allow to fully cool, then check the coolant level


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## Tayiler (May 3, 2017)

I followed the Nissan repair manual step by step for replacing therm, it's in correctly, I have noticed my radiator fans aren't turning on (looked online, said to turn a.c. on and they should come on), and my upper rad hose is really hot while the bottom is cool. Possibly a blockage? Or could it be the rad fans? Maybe they are turning on, I'm not sure how reliable the ac thing is. I just usually doubt where it's two separate cooling issues right after the other, when I seldomly have issues with the car ever... but that could be wrong. I also have bled the coolant of air pockets 3 times now, following Nissans repair manual, still no difference, no heat control difference, it's still blowing cold. My water pump seems to be working and the serpentine belt is also recently replaced so it shouldn't be the problem. I still want to know also why the rpms are rising at idle, they sit at about 1600 now at idle in neutral... what's that about? A vacuum leaks maybe? I seen some smoke (or steam, couldn't tell) by that general area but i could barely see it and couldn't tell exactly where it was coming from, maybe the overheating engine melted the hose? I have had this happen once before on the top radiator hose and had to replace it


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## Tayiler (May 3, 2017)

I really think for some reason that the coolant is not flowing through the engine. Before I replaced the therm, if it started overheating I would manually switch to second because when i ran at higher rpms for a short time it would seem to kinda reset the thermostat back to normal... That's because the water pump was running harder. I didn't do that a lot though. Now I cant even do that, and it goes alot hotter than it ever did before replacing the therm


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