Hitmo

Hi guys,

Having a bit of trouble with my 97 DC2 R.

Just went for a little drive to get some petrol, got stuck in a bit of traffic on the way back and the temperature needle went up to half way on the temp gauge, as soon as I started moving it dropped back down to normal (on the line just before the middle) but happened several times before I got home.

Haven't had a proper chance to have a look at it yet but when I got home the temp was just above normal and the fan wasn't working, coolant in the overflow tank was a little low but not by alot, the engine was still hot at this point so I thought it was normal.

Any ideas what it could be? I haven't had any engine work done recently, and the thermostat was replaced about 2 years ago (according to the previous owner) and I've never had any trouble with it warming up or reaching normal temp.

I want to test if the actual fan is working by jumping it, do I just follow the wiring off the fan back to the thermostat house, remove the connector and put a piece of wire between the 2 pins?

boarderfatty

iTrader: (1)

Ok first of all,

The problem with your temp climbing when the car is sitting idle, and then coming right back down again as soon as you start moving is somewhat common. Your motor is probably not overheating, the problem is your water pump isnt moving enough water around when the car is sitting idle, so a small amount of water near the sensor gets very hot and as soon as you start to load the motor again and gets the revs up, the water circulates enough to displace the water which is heated locally and the temp returns to normal. That is if the temp drop is very fast as soon as you start moving/rev the engine.

Now if your fan isnt actually working...

First thing to do, check fan fuse, if it's good, then start the car and let it idle up to operating temp, if the needle passes the halfway mark and the fan still hasnt came on, then yes you have a problem and its more than likely the temp sensor for fan switch.

Thats my 2 cents anyway.

Hitmo

Thanks for the reply

Yes the temp dropped straight away when I started moving, I'll check the fuse first thing tomo, if its good then I'll try and jump the fan to make sure the motor in it is still working, is the method I outlined above for doing this correct?

Also where is the temp sensor that controls the fan switch? Is it the one under the dizzy?

Quick99Si

The 1-wire sensor under the distributor drives the temp gauge in the cluster. That sensor is next to useless for troubleshooting, especially if you have any air pockets in the coolant. It's a separate circuit altogether anyway. The ECT sensor is the one used by the ECU to read temp, while the actual thermoswitch controls the fan in a stock setup. Don't worry about the ECT as that's not related to this problem (it's used for things like VTEC control, temperature-based fuel/idle speed control, etc)

And no on your test, if you jump the connector on the fan side, you really won't do anything You need to supply 12v to the fan and ground it to test the fan motor. Check the fuse first as mentioned.


http://www.acurapartswarehouse.com/e...-sensor-3.html

#10 is for gauge cluster temp
#11 controls fan activation/deactivation <--- inspect/test this badboy

Hitmo

Right I've checked the fuse its fine, pulled out the relay and it didn't smell like it was burnt out, but I've got a spare one out of a jdm eg vti that has the same numbers on it, will it be the same?

Also jumped the fan and it came on straight away, so I think its down to the fan switch. Going to bleed the coolant just incase there's any air in the system and double check the fan isn't coming on. I can't seem to find a bleed nipple on the engine so do I just need to run the car with the rad cap open, put the heater on full blast and squish the pipes?

Hitmo

Right I've checked the fuse its fine, pulled out the relay and it didn't smell like it was burnt out, but I've got a spare one out of a jdm eg vti that has the same numbers on it, will it be the same?

Also jumped the fan and it came on straight away, so I think its down to the fan switch. Going to bleed the coolant just incase there's any air in the system and double check the fan isn't coming on. I can't seem to find a bleed nipple on the engine so do I just need to run the car with the rad cap open, put the heater on full blast and squish the pipes?

Quick99Si

The radiator has a valve on the bottom. Older B-series engines had the screw you were probably looking for it, but nothing "recent" as far as I know.

The accepted process to bleed the system is to open the rad cap when cold, turn heater to full blast, let fan come on twice while watching/logging engine temps, refill with cooland as bubbles come up and displace the water in the rad neck. Jacking up the front end of the car as high as possible + massaging the hose helps

Hitmo

Thanks for all your help guys, I bled the coolant and the fan kicked in! Don't know if it had anything to do with me playing around with it or it just came on randomly but had it in traffic on a hot day and everything seems to be fine. I'll keep an eye on it over the next couple of days but hopefully its fixed itself!

Quick99Si

I'm curious if the coolant came out relatively clean or if it showed any signs of corrosion. Maybe the coolant flush "washed" the thermoswitch to the point where it's functional again?

Hitmo

No it was quite clean, changed last year so not too bad.

Question, if the temp gauge goes above normal will the fan stay on constantly until normal temp is regained?

Quick99Si

Once on, the fan will not turn off until a few degrees (5F?) under the original "on" temp. It doesn't have a timer like most rear defoggers if that's what you're asking.

Hitmo

Yeah thats what I wanted to know, I wasn't imagining it then lol

If it ever goes over again il change the thermostat and fan switch just to be sure.