Ugh, another thread :P Sorry guys.

Quick one this time, I have a slight feeling that one or more of the fan relays in the engine fuse box are boned, so I figured I might replace them. From what I can hear, my non-AC fan (driverside) only kicks in at HI speed. I'll just replace them and see if it fixes it. Heres the question about it though, I don't have phsical access to my car to check what relays I need for the Low/Med/Hi functions, so can anyone shed some light? Are they all the same rating or do they differ?

And is it normal for my engine to be running fairly hot to the touch? The temperature gauge reads just under half way and always does when it warms up, however, if I grab the coolant pipe that leads to the top of the rad after the car has been running (not after a thrashing, just going for a drive around town) its fairly hot. With a bit of aggro driving mixed in it's too hot to grab. Is this normal for the engine to be fairly hot? I don't believe the FG falcon runs this hot unless you touch the engine itself, but theres 14 years between them.

What sensors/temp probes etc should I look at checking/cleaning in the engine bay to ensure I don't overheat it?

Cheers.

Your temperature is spot on. Mine always sits just under half when warm. It is normal for the hoses to be hot to the touch. If your coolant is fetting a bit old, change it. Change the hoses as well.

It might also be worthwhile to check your coolant temperature sensor. This can play up.

From what I can hear, my non-AC fan (driverside) only kicks in at HI speed

I can only assume that you are talking about your radiator fans. In that case, both the fans will kick in on a single speed only.... they are not speed regulated or will they alter in speed pending temprature, they will alter in how long they stay on for pending on engine/water temprature and if you are running your AC. Also usually (someone correct me if i'm wrong) the drivers side fan is the A/C fan and the passenger side one is your engine cooling fan. Im sure there is a more techincal explanation.


I don't have phsical access to my car to check what relays I need for the Low/Med/Hi functions

The fan relays are the same as your head lights, swap them and if lights don't work you know the relay is stuffed.



is it normal for my engine to be running fairly hot to the touch?

Yes, yes it would. Heat builing up in a confind space like your engine bay/radiator will make the parts on the outer side warm up too. Hence after driving a while, your bonnet will feel rather warm. Just like putting boiling water into a cup.... the cup will get hot until the water cools as the heat needs to disperse somewhere!

I can only assume that you are talking about your radiator fans. In that case, both the fans will kick in on a single speed only.... they are not speed regulated or will they alter in speed pending temprature, they will alter in how long they stay on for pending on engine/water temprature and if you are running your AC. Also usually (someone correct me if i'm wrong) the drivers side fan is the A/C fan and the passenger side one is your engine cooling fan. Im sure there is a more techincal explanation.

The fan relays are the same as your head lights, swap them and if lights don't work you know the relay is stuffed.



Yes, yes it would. Heat builing up in a confind space like your engine bay/radiator will make the parts on the outer side warm up too. Hence after driving a while, your bonnet will feel rather warm. Just like putting boiling water into a cup.... the cup will get hot until the water cools as the heat needs to disperse somewhere!

Fair enough. I figured it must have had some type of automatic speed control hence the 3 speed relays. "I'm starting to get a tad over my operating temp, better kick the fan in on low" through to "holy crap, it's 40 degrees and i'm sweating cos this blokes bashing me off the limiter, HI speed it is".

I'm aware that an engine will get naturally hot. just concerned that if I go for a drive (say, doing some laps on a friday for a few hours) then when I park it in the car port and return a few hours later, the radiant heat from the engine has heated the garage a few degrees. If I was to work on it, there would still be enough heat radiating out of it to make a camp fire redundant.

I may be 100% wrong, however maybe the LOW and MED relays are boned, and the car attempts to kick them on at low and medium respectively. ofcourse it thinks they are on, though they aren't. temp keeps going up, to the threshold of the HI speed option. at this point my fan comes on blaring at max speed, dropping the temp down to the threshold of medium. the ECU or whatever controls it activates the defective MED relay, nothing happens until it climbs back up to the threshold.

However I don't completely grasp this understanding. I'm simply applying my knowledge of computer water cooling and common sense in the subject. Maybe Mal can shed some insight?

Is there a way of testing the relays?

Lastly, I dropped in to Autobarn and whatdyaknow, the relays are a specific mits part, dammit. Are they purchasable somewhere or are they only available from mits? My local mits service centre/part store has to order them at $25 a piece.

Mate reason for 3 relays is that one fan has a hi-low speed and then the other is high.

When you turn on the air con both fans should turn on....... undo th coolent temp sensor (near thermostat) and both fans should turn on. Unless you actually see the dash board meter moving, don't worry about it. I saw it moving when the low speed motor blew in my one.

Sounds VERY NORMAL, close the bonnet and save your $$$.

Depends on what model your car is and it's options, you'll only have low + high or low + medium + high.