# Once-in-20yrs issues



## SuperStock (Dec 31, 2003)

Hello, I've been on here for 6-7yrs, off and on. Car has been drama free for 20yrs until last week...

Issues have developed with the B12(sedan 2dr, 5sp, no AC, no PS)

Radiator blew on a short trip to the store. Limped it home a very short distance. When it blew, my idle shot up to 2500.

I replaced both radiator hoses and installed a new thermostat. I added coolant, then continued adding coolant after I started the car...

Soon after starting the car, I noticed the idle was still hovering at 2500... Adding to this, the temp gauge was zero. Once the car warmed, the idle calmed back to 900 and the gauge read 3/4 hot. Before all this, the temp would read 1/3 hot under normal conditions...

I have cleaned the AIV and FICD, and have yet to put it all back together. Any suggestions? 

Thanks
Mike


----------



## jdg (Aug 27, 2009)

How low is the coolant now after that run?
I'm leaning towards a blown head gasket due to a bit overheating and just plain old-ish motor. A compression check will tell you if that's the case.
Maybe you've still got an air bubble in there and still need to add more coolant.
Maybe water pump went south, which took out the radiator due to the bit of an overheat.


----------



## SuperStock (Dec 31, 2003)

the water is pumping fine, i ran thermal tests of the radiator, block and hoses. block is normal temp, head is fine, and there's an 80degree drop from the radiator inlet to the outlet, before the fan kicks on. 

Once it warms, the car idles down normally, and the temp gauge reads crazy hot when i know it isn't. I put a premium Napa thermostat in it... havent done a compression check tho. ran a radiator compression test, and its fine, its in perfect health. 

*BTW its a GA16i lol sorry ive forgotten to mention that, hvent posted on here in a very long time.


----------



## BeyondBiscuits2 (Jan 18, 2006)

It could also be your coolant temperature sensor. When an engine runs hot, it usually kills your CTS just like your thermostat. The one that supplies your gauge is on the cylinder head. Just buy a new one and see if that helps... it shouldn't be more than a handful of dollars.


----------



## bob89sentra (Sep 15, 2005)

B12, with a GA16i?
The temp sensor for dash gauge is located beneath the throttle body sticking out the back of the intake manifold, and is a big pain to get at and replace.
My bet is your wax pellet fast idle cam is plugged.
I have had tons of experiance with overheating, and that is the 1st thing I check now.
The thermostat is a dual action thermostat, and has 3 coolant bypass lines. the first is your heater core for heating the car, and the 2nd is the small 1/4" line the runs from the back of the thermostat housing to the intake manifold, and turns a 90 degree bend.
The third runs from the side of the thermostat housing right next to the heater core hose and runs into the bottom of the intake manifold, and through the fast idle cam. When the fast idle cam gets plugged with junk (usually bits of RTV) it will cause you to have a faster idle, and it also causes the engine to run hotter.
If you take the fast idle cam off, and remove the actuator and clean it you should be able to get it going right again. Beware of stripping the bolts on the fast idle cam, the 3 phillips on the side are usually very tight, and the 1 that holds the actuater in with a plate you might need a hammer type impact screwdriver.

The reason the fast idle cam causes overheating? Well, it took me 4 years of replacing every component, sometimes even 2-3 times to track this down. The dual action thermostat blocks the main flow through the radiator, but a second plate and spring allows flow through the 3 bypasses I mentioned before. The first 2 (90 degree hose and heater core) let flow through the engine, but the water flow is on the back side of the 2nd action of the thermostat and it does not heat up the main body of the thermostat very well, so the 3rd line which goes through the intake manifold and fast idle cam directs coolant on the body of the thermostat, heating it up properly. If the fast idle cam is plugged the flow to the body of the thermostat is stopped or slowed and in turn the thermostat is much slower to open and the engine will run hotter than normal. 
Good luck,
Bob


----------



## bob89sentra (Sep 15, 2005)

also there is a coolant bleed screw you can remove to help get all the air out, it is on the driver side of the engine on the cylinder head, and can be removed with a 10mm wrench, it is below spark plug #4 and to the right. I usually remove the plug and add coolant till water is pouring out and the replace the screw and finish filling it up.


----------



## SuperStock (Dec 31, 2003)

Bob for president!

I replaced the CTS and it still reads too hot... 

Bob, should I just bite the bullet and remove the entire intake manifold and do this? The wax pellet FICD is to the driver's side of the head, iirc, is this correct? I didn't bother cleaning the idle-up solenoid, as it's a pain... but it's easily done when removed from the vehicle.


----------



## dreamteam (Jul 29, 2005)

*Bleed screw*

Open the 10mm bolt below the spark plug wire loom when the engine is cold. Pour in more coolant until the stream is steady. You have air in your system. 
Idle increases and coolant temp guage reads hot because air is in the head.


----------



## bob89sentra (Sep 15, 2005)

The FICD is a solenoid on the back of the intake manifold, it is different from the wax pellet fast idle cam. The wax pellet fast idle cam is on the driver side of the throttle body right above the throttle cable with the hose going in the front and out the back









It has 3 large phillips head screws holding it to the throttle body, and after removed you will see the 1 that holds the actuator in place.

Again, you may want to try to bleed the air out of the head with the bleeder screw to see if it helps as it is an easy thing to try.


----------



## BeyondBiscuits2 (Jan 18, 2006)

Somehow I thought he said GA16DE, but nonetheless, I'd go with Bob on this one. He knows his GA16is. You have to love '80s technology...


----------



## SuperStock (Dec 31, 2003)

Dreamteam, thank you very much as well as Bob. 

All the right people have stuck around thru the years on ths site and I am extremely grateful to be part of this community.

I will tell you how it goes. Thank you all again!


----------



## SuperStock (Dec 31, 2003)

It's all working great, thank you guys again! turns out it was the air-in-head thing. 

at nearly 360k, it still runs like it did brand new, not even a hint of lifter tick. amazing.


----------



## SuperStock (Dec 31, 2003)

Now, only when warm, the car is idling between 1200-1500RPM, and runs on the hot side. I can hear a solenoid click, and the idle goes down for an instant, then goes back up. This sounds like a fast idle cam issue. Am I correct?

Thanks again


----------

