water temperature problem

**pgilliam1** · 04-24-2012, 14:55

Originally Posted by goldNSX

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.

I did not say pgilliam1 is wrong with his vote (we'll see after you did all tests).

I didn't vote for "gauge problem". I said gauge "sending unit" problem. I haven't read of a bad temp guage on these cars yet. The coolant leaking at the radiator could also indicate loss of pressure which could cause a spike in temp. Finding that leak would be first on my list

.

**pgilliam1** · 04-24-2012, 14:57

Originally Posted by 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.

Yes, the AC condensor fans are other fans (there's 2 of them in front of the front wheel wells.

**comtec** · 04-24-2012, 18:25

Martin,
Did you say you checked fuse #31?

Have you checked for voltage at the fan power plug?

Mike

**goldNSX** · 04-24-2012, 22:41

Originally Posted by pgilliam1

Yes, the AC condensor fans are other fans (there's 2 of them in front of the front wheel wells.

DITO, you can feel the air blowing with your hand in front of the AC condensers.

**Martin_VTEC** · 04-24-2012, 23:35

Originally Posted by comtec

Martin,
Did you say you checked fuse #31?

Have you checked for voltage at the fan power plug?

Mike

The fuse #31 was the first thing i checked, it's ok.
I did put 12V directly to the fan-motor, and the motor is ok, I did not measure the voltage in the plug/connector.

So I guess it has no point doing that? because if there would be voltage in the connector, the fan-motor should work.

**comtec** · 04-25-2012, 01:43

Originally Posted by Martin_VTEC

The fuse #31 was the first thing i checked, it's ok.
I did put 12V directly to the fan-motor, and the motor is ok, I did not measure the voltage in the plug/connector.

So I guess it has no point doing that? because if there would be voltage in the connector, the fan-motor should work.

The fan is operated by a switched ground so you should see 12-14 volts at the fan power plug.

Mike

**Martin_VTEC** · 04-25-2012, 01:59

Ok, so when the ignition switch is ON, I should see 12-14 Volts whatever the temperature of the car is? I don't have to start the engine?

I will check that tonight, and I will check the coolant-temperature-sending-unit described on page 23-136 in the manual

**comtec** · 04-25-2012, 02:32

Originally Posted by Martin_VTEC

Ok, so when the ignition switch is ON, I should see 12-14 Volts whatever the temperature of the car is? I don't have to start the engine?

I will check that tonight, and I will check the coolant-temperature-sending-unit described on page 23-136 in the manual

It's always hot even when the switch isn't on. Looks like the plug is below the fan resistor plug you checked before. The +12v lead is White on the harness side of the plug. Be aware the ground is also white but has a blue stripe. Only check the white wire and with your other lead (black test probe) on any chassis ground.

Mike

**Martin_VTEC** · 04-25-2012, 10:00

Ok, I measured the connector like u told me, and it reads 12v...

So the next thing was trying to test the coolant-temperature-sending-unit described at page 23-136:

But I can't find that bloody thing

Al connectors that I see have 2 or more wires.
And the only Yellow/Green wires I can find is this (I disconnected it for the photo):

But this isn't the coolant-temperature-sending-unit right ?

**goldNSX** · 04-25-2012, 10:30

Wash down the engine compartment too, you'll be able to find it then.

Still confused, did you check if the radiator fan is coming on at idle after a warm-up drive?

**Martin_VTEC** · 04-25-2012, 10:36

yes I must wash my car

and no, haven't done a warm-up drive yet, only 20+ minuts idling.
It's raining hard outside, and i don't want to replace the rear ignition coils again from al that rain ..

tomorrow in the evening when the weather is good, I will drive with my mechanic
and before that I have also replaced the O-ring and the plug from the radiator.

But I don't expect the fan to go on again...we wil see.
But does anybody have a photo where that sensor is located ?

**goldNSX** · 04-25-2012, 10:47

Originally Posted by Martin_VTEC

and no, haven't done a warm-up drive yet, only 20+ minuts idling.
It's raining hard outside, and i don't want to replace the rear ignition coils again from al that rain ..

I understand your point.

I would do this test first because the radiator fan HAS TO COME ON during idling of a completely warm engine. It's very quiet in my car so you better open the hood and check it visually and by the feel for hot air. Just beware your hands of the fan.

You can speed it coming up by reving it steadily above 3k rpm or whatever rpm you like.

I stress this point because the fan has to run everywhere in stop-and-go traffic and so on. You can fix all the other things but if the fan is not working you'll have the same problem in the future again and blow head-gaskets is not a thing people like to pay.

**pgilliam1** · 04-25-2012, 11:00

Originally Posted by Martin_VTEC

Ok, I measured the connector like u told me, and it reads 12v...

So the next thing was trying to test the coolant-temperature-sending-unit described at page 23-136:

But I can't find that bloody thing. But this isn't the coolant-temperature-sending-unit right ?

No. The guage sending unit is right next to where the hose from the coolant tank connects to the engine. The connector just pulls off. If it test OK, make sure to use teflon tape or pipe dope when reinstalling.

**comtec** · 04-25-2012, 11:33

Martin,
This sending unit only controls the gauge not the fans. This is the best i can do without my car.

Mike

**Martin_VTEC** · 04-25-2012, 11:49

Mike, is the location of the coolant temperature gauge sending unit in your '97-'99 any different than mine ?

**comtec** · 04-25-2012, 12:11

Originally Posted by Martin_VTEC

Mike, is the location of the coolant temperature gauge sending unit in your '97-'99 any different than mine ?

Martin,
It should be in the same area. My manual only lists 97-05 so that's why it shows 97-99 on the picture.

Mike

**Martin_VTEC** · 04-25-2012, 13:10

aha, located that sensor, did the test and as described in the manual a couple of post above, the needle of the gauge was heading above, but not to the "H" mark.
It stopped just under the half, where it stopped yesterday when it was idling..

Did it passed the test ? I guess so

I could not get a good reading from the other test, where u measure the resistance between the postive terminal and the ground.
My multimeter was on 2 K Ohm, and on the gauge there was 18,2....
I will measure it again after a testdrive

**comtec** · 04-25-2012, 14:25

Martin,
The K ohm setting is too high for this test. I think you would need to be on the 200 setting. The test shows 142ohm cold with decreasing resistance as the temp rises.

Mike

**Martin_VTEC** · 04-26-2012, 23:32

Ok, last night I replaced the plug and O-ring, had removed al off
the connectors for the 356832 time, triple-checked the relais.

So, I took her for a spin, after coming back after riding for 15 minutes, stepped out of the car,
wait 1 minute and.....the radiator-fan and the fan in the engine-compartment was going on...
The needle is not coming furter than just under half.

I don't understand it.. all the connectors were good and clean, I haven't located the problem, probably a bad connection somewhere.
I guess I'm just riding the first months close to home and test it

After drinving some more, ik stopped, checked the fan, it was going on after 1 minute after I stopped again, but this time only the radiator-fan was on, not the fan in the engine-compartment.

Is this normal? so it wasn't hot enough in the compartment that the fan wasn't going on ??

When I got back home, I saw some tiny tiny bubbles round the hose that is fitted on top on the radiator driverside, and a wet spot (2" diameter) under the hood on the passengers side, the radiator looks good, but maybe it has a tiny crack or something, I keep it in mind and when it is getting worse I replace the radiator and the 2 hoses this summer.

Thank u guys so much for al the help, I really appreciate it

**goldNSX** · 04-27-2012, 00:41

Sounds good. Your radiator fan is running, that's the most important. A bad connection? Maybe. If you think that's the cause it might be good to look deeper into it.

I'm not sure about the engine compartment fan, I dismounted mine anyway, definitly after going CTSC.

Bubbles and spots: it looks as if the cooling sytem of your car gets older and starts to leak or fail. Most people here on prime recommend the replacement of all 22 hoses and so do I. The NSX is not prone for radiator leaks but after more than 20 years...I'm waiting to have to replace mine which still has no sign of any leak. If you (strongly recommended

) wash down the front bay and check right after a short drive where the bubbles and spots come from you may get away with changing the hoses only.

Wet spot on the driverside: has the A/C been ON? I get spots on the floor when the A/C was ON. The spot is the moisture forced out of the evaporator through a hose somewhere on the driverside of the front compartment.

Good luck!

**comtec** · 04-27-2012, 02:06

That's great Martin,
It could just be a pin hole in the hose. I have seen them spray when the pressure builds up in the system. Dry up the the antifreeze that you see and buy some cheap rubber tape. Wrap it around the area where you saw the bubbles on the hose. Drive it around for a while, maybe a few days and if the puddles go away you know it was the hose so you can replace it.

Mike

**Martin_VTEC** · 04-27-2012, 02:07

The wet spot is at the passengerside, under the bonnet/hood.
I think a crack or something or a tiny leak in the radiator which sprays the water up when i'm driving and pressure is building up
I will make some pictures of it tonight or tomorrow

on the passengerside the hose is at the bottom of the radiator, so i guess it's the radatior,

Oh, there is a Low fan relay and a high fan relay, does that explain why sometimes the fan in the enginecompartment isn't turning? in some curcimstances ?

**comtec** · 04-27-2012, 11:37

Low fan relay operates the fan at low speed starting at 84C and when the temperature reaches 90C the high fan relay kicks the fan into high speed. The engine compartment fan has it's own relay and only comes at the same time as the high fan. Must have been the wiring for the coolant temperature sensor as that and the fan control unit are about the only thing they have in common.

Mike

**Martin_VTEC** · 05-02-2012, 23:30

Thanks Mike.

I've taken NSX the last couple of days for a few test drive's and the fan is still working like it should.
But I'm getting worried about the radiator, I think it has at least 1 little crack
And the hose on the driverside need to be replaced I think
It is hard to take a good picture, because probably when I'm driving, I loose a little coolant, and when I stop to look, I see a little wet spot, it dries up very fast and leaves a white/grey spot because the radiator is hot.

And these are a few wetspots under the hood, exactly at the place where the wet spot is in the pictures above (And yes, I need to clean under the hood).

The following pictures are I guess responsible for the wet spot under te hood at the driverside:

It doesn't look real bad when the car is idling, but when I'm driving it's probably under pressure and spraying it out of the radiator and a little at the end of the hose.

I can still drive and I can't see any difference in my coolan level just yet, but changing the radiator and the 2 hoses isn't a bad idea...

Is the OEM honda radiator the best 1 to buy? or are there better alternatives ?