Radiator Problems??

[GtRider]

need help!!!
when i drive my G for a while my temperature light goes sky HI!!!
when i pop my hood my overflow tank is BOILING!!!
i dont think my fan is coming on.
does 2 fans supose to come on or just 1?
i checked the fuses for the fans and there good!
what TO dO?????

[A380Driver]

Umm what I can think of right away is check your thermostat...
Also, i believe one fan is the rad fan the other is the ac condensor fan...depending on your car setup....i do believe man and auto trans are different as well...

[ty423]

try checking if the bottom hose is cold and your top hose is hot.....I think then it is most likely the thermostat...therefore not opening for circulation....something like that...happened to my brothers camry

[P10DET]

Originally posted by GtRider
need help!!!
when i drive my G for a while my temperature light goes sky HI!!!
when i pop my hood my overflow tank is BOILING!!!
i dont think my fan is coming on.
does 2 fans supose to come on or just 1?
i checked the fuses for the fans and there good!
what TO dO?????

Both fans should come on at the same time. If the fuses are good, it could be a relay. Try switching the relays and see if they switch which fan is coming on.

I had a similar problem with my SE-R. I finally decided to check the relay, which is funny given the fact that I hate electronics and electronics hate me. I pulled the relay, looked at it, said "yep, it's a relay" and reinstalled it. Both fans worked ever since. Go figure.

[GtRider]

i checked all the fuses and the relays!
they all are good.
both radiator hoses get hot!
need help!!!!
whatz wrong wit my G????????

[T4 Primera]

What year is your car? mileage? do you keep the coolant good? Check fan, radiator core for blockages (look in the filler neck), thermostat, and finally waterpump.

[GtRider]

i have a 94 G auto about 135,000miles
i keep the radiator fluid in good condition
earlier today i changed the coolant. i flushed out the system with a water hose.
wheres the thermostat?
and waterpump?

[T4 Primera]

Originally posted by GtRider
i have a 94 G auto about 135,000miles
i keep the radiator fluid in good condition
earlier today i changed the coolant. i flushed out the system with a water hose.
wheres the thermostat?
and waterpump?

Is the fan cutting in? Start your car and let it idle while stationary so the temperature rises. The fan should operate BEFORE you get into the danger zone on the temperature gauge, otherwise stop the engine and allow to cool off.

If the fan didn't cut in, and you've checked the fuses relays etc, then the fan itself may be faulty.

The radiator fan is most likely the problem because the fact that your hoses both heat up indicates good flow. This rules out the thermostat and the waterpump. Also, the bottom hose should run noticeably cooler than the top one if the fan is operating properly.

Did you notice if the cooling passages in your radiator were clear last time you changed the coolant? (That's assuming the position of the filler neck allows you to see the core passages)
Sometimes when a car overheats it loosens up any crud in the engine and conveniently dumps it all into the radiator and blocks it up. Flushing doesn't always remove it as it can jam in the narrow passages. I once had to take a radiator to a specialist shop so they could remove the tanks and rod out the passages.

Also, did you follow procedures for coolant renewal utilising any bleed screws on the engine?
If not, you may have airlocks or steam-pockets in the system. On my car one of these bleed screws is located right next to the thermostat meaning that is a place that can be airlocked!!

The thermostat is located inside the thermostat housing (a half spherical shaped aluminium fitting with a coolant hose attached to it) beneath the distributor at the front of the engine. You can test it by placing it in water and raising the water temperature. At the specified water temperature (usually stamped on the thermostat) the thermostat should open.

The water pump is located under all the belts and stuff at the pulley end of the engine (I think). It is difficult to tell if it stuffed without removing it so I'd check everything else out first. It is unlikely this has failed if the coolant has been looked after. If you get to this point then I can give you an idea for testing it without removing it.

I'll have a browse through my Haynes manual after work and see what I can find out and then post more specific details. Oh, and try not to overheat your engine again or you'll likely be up for a new one.
Later

[P10DET]

Originally posted by T4 Primera
Also, did you follow procedures for coolant renewal utilising any bleed screws on the engine?
If not, you may have airlocks or steam-pockets in the system. On my car one of these bleed screws is located right next the the thermostat meaning that is a place that can be airlocked!!

Bingo!!

I suspect that is the problem.

Go here:

http://www.zotz.com/nissan/proc/sent...ant_change.htm

[T4 Primera]

Ok, checked my Haynes manual and found that these cars don't have fan switches - the fan is controlled by the ECU which utilises the engine temperature sensor - so I've deleted that mistake from my earlier post:o

Hayne's list of causes for overheating is:

Insufficient coolant in system
Pressure cap faulty
Airlock in cooling sytem
Thermostat faulty
Electric cooling fan faulty
Inaccurate temperature gauge sender unit
Radiator core blocked or grille restricted
Ignition timing incorrect or ignition system faulty

The engine temperature sensor used by the ECU brings up an engine check light if it fails.

So there's plenty there to check out if you need to. There are ways to test the above, so if you need to, just ask.

[P10DET]

Originally posted by T4 Primera
Ok, checked my Haynes manual and found that these cars don't have fan switches - the fan is controlled by the ECU which utilises the engine temperature sensor

Yep. There are two water temp sending units. One has a simple spade connector and that sends a signal to the gauge on the dash. The other has a red connector and this is the ECU sending unit.

Both are located near the oil filter at the point water enters the head.

Originally posted by T4 Primera
So there's plenty there to check out if you need to. There are ways to test the above, so if you need to, just ask.

I still think that insufficient bleeding of the cooling system is at fault here. Once I saw that the coolant was replaced, it became clear. The SR20 engine is extremely sensitive to air in the cooling system.

Rebleeding the system is the first thing I would do. When I installed the DET in my G20 I bled the system several times to be sure it was proper. Bleeding it the first time took care of a good amount of overheating.

[GtRider]

thanks for all the info!!!!!
i went to the junkyard today and picked up another fan because 1 of mines broke.
got a question...
which fan is which?
is the right fan the engine cooling fan or the ac cooling fan?
the left ac or engine?
when i drive none of the fans come on, but when i turned on the ac both fans came on!
my friendz were saying its probably a sensor!
so most likely its the sensor thats not making the engine cooling fan come on, huh?
but where is the sensor located and how much does it cost?
also, my check engine light is on and it doesnt come off so i have to get my car diagnosed

[P10DET]

Originally posted by GtRider
also, my check engine light is on and it doesnt come off so i have to get my car diagnosed

Hmmm. Interesting. I'll bet the check engine light is caused by whatever failure is causing your fans not to come on. The fans are supposed to come on anytime the ECU registers some fault because that is the "safe" thing to do.

[GtRider]

so i should have my engine scanned
to see whats wrong with it?
you think its the sensor?

[T4 Primera]

Originally posted by GtRider
so i should have my engine scanned
to see whats wrong with it?
you think its the sensor?

When did the engine check light appear? with this overheat problem or was it there already?

You could take it to the dealership if you don't feel confident tackling this or you can have a go yourself. If you do it yourself you'll gain valuable know-how and confidence in maintaining your vehicle.

There is information on this forum for extracting the ECU fault codes yourself. It ain't that difficult once you have the right info and you don't need any special tools. IIRC there is a screw on the ECU in U.S. cars that you turn to enable diagnostic mode. Again IIRC, in diagnostic mode, the codes will be flashed at you by an led on the ECU.

There is also a way to reset the ECU just in case the engine check light is showing an old code that hasn't cleared itself yet, which would otherwise not clear until 50 engine starts. There are many people on the forum that can help you with this. My Haynes manual is written for Primeras and the procedure for diagnostics is a little different to yours.

Once you have the fault code that is causing the check engine light it'll very likely point you to the problem. If it points to the engine temperature sensor (code 13 on my car) then you know where to look. Even if it does indicate the sensor, it may still be ok and just not giving a valid reading to the ECU because of airlocks in the system.

If it comes to it, the sensor can be tested to confirm it's bad before replacement but in no circumstances should it be tested on the car or damage to the ECU may result.

Read P10Det's post again for the location of the engine temperature sensor - oh, have a quick look at the sensor just in case the terminal has fallen off the end of it - sometimes, if you're lucky, it can be as simple as that.

I'm sure this problem is solvable without having to resort to the stealership but it's your call of course.