water temperature problem

[goldNSX]

...how can i check the level in de radiator ?

Part of the bleeding procedure is to open the upper plug you already ordered and poor coolant in the reservoir in the engine bay. As soon as it starts flowing out of the plug the radiator is full. As I recall this is the first plug to close while bleeding.

As for checking you can open the plug but don't remove it. As soon as you get coolant out of it it's full.

 

[Martin_VTEC]

-I checked the fuse #4 in the dash fuse box, and it's OK

-I disconnected connector from the radiator fan motor and I tested the motor operation by connecting battery positive to the A terminal, and negative to the B terminal. The motor run's smoothly

-I did the radiator resistor test described in the manual:





That does't look like it's good

This is another picture from the settings from the multimeter (don't look at the lcd screen, i haven't got it connected):



These settings are ok right ?

 

[comtec]

That looks ok on the meter i think. Does that mean 0-200 ohms?

Reguardless, the resistor is only on the low side relay. The temp you had should have kicked in the high side. Also it shouldn't effect the compartment fan.


Next step should probably be verifing the wiring from the fan control unit.

Mike

 

[Martin_VTEC]

But the specifications should be between 0.54 and 0.66 ohms
I have 1.1 ohms. Isn't that a bad thing ?

I haven't measured the 3 TW-sensors yet. I guess doing the test on page 11-48 in the manual? I haven't got any error-codes.

 

[goldNSX]

But the specifications should be between 0.54 and 0.66 ohms
I have 1.1 ohms. Isn't that a bad thing ?

No, that's ok for me. It's quite challanging to measure low resistance.

Next thing to measure would be volts. It should be around 12V at the switch.

 

[comtec]

I meant your meter setting looks correct. The 1.1 is different from the .6 i show but the fan would still work if that's bad.

Mike

 

[Moses]

Maybe a new gauge is needed.......

 

[Martin_VTEC]

@Mike:
Ok thank u

@goldNSX:
Ok, so measuring the 3p connector from the resistor ?

Sorry for al these questions, i'm not so good in the electrical stuff:redface:

 

[comtec]

The resistor is only on the ground side of the low fan relay. Did you check both the low and high relays to make sure they are good?

Shown on 23-112 and 23-121

Mike

 

[Martin_VTEC]

@Mike:

I can test the continuity between the A and B teminals while the relay is still in the car ? because as described in the manual: the C and D terminals should be connected to the battery..

And does anyone has a picture where the 3 TW-sensors are located?
In the manual, the're mostly exploding views, and can't see where they are located
And there is only 1 section in the manual where it´s described how u can measure a TW-sensor, but it doesn´t describe which tw-sensor it is , and I don't have error codes

 

[comtec]

Hey Martin,
Look at the thermostat, your third picture. The sensor that controls the fan is called THERMO SENSOR and it's in the front of the thermostat housing. It shows thermo sensor but in the 1995+ manual it is called RADIATOR FAN CONTROL SENSOR. The one you have highlighted is for the gauge.

There is no reason to try checking at the sensor because the same thing can be done at the cooling fan control unit although i don't know if that will tell you anything. I think the cooling fan control unit would be the next place to start looking at anyway. There is no test listed for this but they do show the wiring. Should be able to jump at this location to force the fan on and that would show you if everything is good past the unit or not. It's in the drawing you posted above.


FYI.... It's a good idea to use both the 1991 manual and the 1995+ together. They are sometimes different and it helps. Be aware that i have found numerous errors in the repair manuals, usually to do with wire colors.


oops, missed your first question. No the relay can't be checked for continuity while in the car. The A and B terminals carry voltage when in the car. You could check to see if you are getting power from them but if not you won't be able to tell that it's the relay or a problem before that.


Mike

 

[comtec]

This may help.
Hope you can read it.

Mike

 

[Martin_VTEC]

Thank u for that information, on Thursday a friend of mine comes along and he is a mechanic, I hope he can figure it out with he wires..

So you're trying to say that I should put 12v on the right terminals in the cooling fan control unit to check if the fan works ?

I can see in the picture that the cooling fan control unit has terminals for:
a/c pressure switch, condensor fan, climate control unit.
At the time the engine was hot I didn't had the heater in the car on. It was off.

 

[pgilliam1]

You guys are doing a nice job on analyzing this, but my vote is the temp guage sending unit is bad and the engine wasn't ever overheated. I just base this on reading other posts and having read the guage sending unit has been a known failure on this car. Good Luck!

 

[nsxiest]

Hey Martin,

oops, missed your first question. No the relay can't be checked for continuity while in the car. The A and B terminals carry voltage when in the car. You could check to see if you are getting power from them but if not you won't be able to tell that it's the relay or a problem before that.


Mike

In my 91 I can test the hi and low relays in the horn relay socket (same compartment). i.e. replace horn relay with suspect hi or low relay- horn honks or not.

 

[comtec]

Thank u for that information, on Thursday a friend of mine comes along and he is a mechanic, I hope he can figure it out with he wires..

So you're trying to say that I should put 12v on the right terminals in the cooling fan control unit to check if the fan works ?

I can see in the picture that the cooling fan control unit has terminals for:
a/c pressure switch, condensor fan, climate control unit.
At the time the engine was hot I didn't had the heater in the car on. It was off.

No, if you look at the picture the radiator fan motor receives power all the time from fuse 31. That means the white/blue stripe wire going to the other side of the motor from the relays is a switched ground and you can see that at the bottom of the picture. We can also see that the relays are operated by a switched ground from the fan control unit.

You should be able to unplug the connector from the fan control unit and apply a momentary ground to the green/black stripe wire (low fan) and the blue/red stripe (high fan) one and then the other to see if the fan comes on at both relays. The key would need to be in the run position.

I will be close by the computer today so i can keep looking to see if you have any questions and you are more than welcome to PM or even call me if you need to.

Mike

 

[comtec]

You guys are doing a nice job on analyzing this, but my vote is the temp guage sending unit is bad and the engine wasn't ever overheated. I just base this on reading other posts and having read the guage sending unit has been a known failure on this car. Good Luck!

Could be, if his temp never reached 183 degrees the fans wouldn't come on. That is unless the cc is turned on. That would actually be easy and quick test. Wouldn't have to run the car long enough to over heat. Not sure which setting on the cc causes the fans to come on though.

In my 91 I can test the hi and low relays in the horn relay socket (same compartment). i.e. replace horn relay with suspect hi or low relay- horn honks or not.

Good point Thanks

Mike

 

[Martin_VTEC]

Thank u for your information so far guys, I don't understand everything u say
SO I leave that to my mechanic.

you guys speak about a easy and quick test to see if my gauge is ok ? how can i test that?

 

[comtec]

No i think you can start the car and turn on the ac and it may force the fans to come on. Worth a try and you can see what the gauge shows also. Don't run it too long though. Just enough to warm it up a little and see how the gauge acts.


Mike

 

[Martin_VTEC]

I measured the thermo sensor and when the engine was cold it had a resistance of 20 K Ohm
I started the engine, let it run for more then 20 minutes, the temp gauge reaches almost half in about 12 minutes and stayed there.

The fan didn't came on, the engine wasn't really hot, I toughed the radiator and radiatortubes and they were warm.

slowly released the white plug in the radiator to let a little bit of water out.

After 20 minuts turned of the car , it had only run idle and when I checked the thermo-sensor it had a reading of 1 K Ohm.
I beleive those readings are OK , as stated on page 11-48

I also disconnected the plug from the thermosensor and started the engine.
I beleive that I should get a check-engine light?? There was no such thing.

On thursday I will test drive and check the resuls again.

 

[goldNSX]

You can drive the car a few miles to shorten the warm-up period. To fasten things even more make sure the heater setting is at cold (blue). You should be able to get the fan running at idle. In contradiction to what pgilliam1 voted for above (gauge problem) you should make sure (for the engines savety) that the fan is running if the coolant gets too hot. That's simply the safer bet. :wink:

I did not say pgilliam1 is wrong with his vote (we'll see after you did all tests) I just say it's safer to have the fans running.

 

[comtec]

Can't someone please start their car and see if the fans come on when the AC is switched on? I would by car is too far away. Some setting on the cc should turn them on because there is a wire from it.


Mike

 

[goldNSX]

Can't someone please start their car and see if the fans come on when the AC is switched on? I would by car is too far away. Some setting on the cc should turn them on because there is a wire from it.

The A/C fans always turn ON when the A/C is switched to on. This is not related to the engine temp and the radiator cooling fan (at least on my car where everything is working 100%).

 

[comtec]

The A/C fans always turn ON when the A/C is switched to on. This is not related to the engine temp and the radiator cooling fan (at least on my car where everything is working 100%).

The fan control unit controls the Radiator, Engine compartment and the Condensor fans and the radiator fan control sensor is used by the CC to determine whether the A/C high/low pressure switch needs to used. So far we don't know any of them are working.


Mike

 

[Martin_VTEC]

I did some test with the A/C while idling , put it on cold, hot, auto, but the radiator-fan dit not go an, I could hear something blowing and it did get cold in the car like it should, but the radiator-fan was not spinning.
the A-C fans are other fans right ?

But this time, the gauge stayed perfectly under the middle.

I guess next time let it go idling for a couple of minutes AFTER extensive driving and see what happens with the temp-gauge..

And I always thought that when u pull the connector of the TW-sensor that u schould get a error #6 if u start the car... the CEL is not defect.