i have a 4cyl TR with efi. This car has always run a little hot for a TR, i find they usually sit just under half on the temp gauge but this one sits just over. It had/has many faults in the cooling system when i got it, like a radiator cap that didn't seal, i replaced it and then found the rest of the leaks like the waterpump and the hoses :swearing:
Now i suspect there may be a problem with the radiator fans.
1. Both fans work when the a/c is turned on
2. neither fan works when the coolant sensor is disconnected or connected. ( I didn't disconnect the single wire gauge one)
3. the fans do not switch on with the a/c turned off even when over half on the temp gauge

At what point on the gauge is the first fan supposed to cut in?
Is there more than one relay to control the thermo fans in a TR?
Can anyone scan and email or post on here a copy of the wiring diagram for this circuit?

any ideas on this appreciated, thanks

Hi mate i used to own a TS 4cyl basicly same as TR and it would run at just on Half way or just above (the fan kicks in then) have u tried just starting the car up and letting it sit there for about 15 min to get to temp and then seeing if the fans come on as it took a good 10 - 15 min for mine to come on and it was a rare thing for me hehe

Cheers

Heath

isnt there a second temp sensor for the thermal fan? maybe thats out? Because as you said it doesnt work if its unplugged or if its plugged in, so maybe your sensors gone. Have you tried disconnecting the coolant sensor and then earthing it? that should make the fans go on (makes sense to my limited knowledge of car electrics)

i'm not sure how it wires up in a magna, there are three coolant sensors in the car, one under the manifold one above it and one in the radiator, i know in a vn commodore the fan relay is controlled by the a/c circuit and the coolant sensor via the engine computer, is a magna like this? or is the sensor in the radiator the only one for the fans?

I'm not too sure about the location of sensors, but.....

The Magna has two fans, the left one (if viewing from the front of the car towards the back, then it'll be right) will only turn on when the A/C is activated.

The right one should turn on momentarily once the car has warmed up, basically when the temp guage reads about half.

So to test it, once its warmed up let it sit there idling, the fan should turn on in the space of 15mins. If it doesn't, i'd suggest find a multimeter, unlplug the right fan connector, and test the connector and see if it gets a reading at some point in time, ie. you may have to wait 15mins.

The Magna has two fans, the left one (if viewing from the front of the car towards the back, then it'll be right) will only turn on when the A/C is activated.

The right one should turn on momentarily once the car has warmed up, basically when the temp guage reads about half.


My TR has both fans running at times and my a/c isn't turned on :S, is my car faulty? lol.
My fans turn on when i start the car, then turn off (until it warms up) and then the big one definatly goes agian, not sure about the smaller one.

hrmm, ill check the wiring diagrams sometime later this week, but mine and many others ive seen dont do that.

When you say the fan turns on when you start the car, is that when its cold with the A/C off??? :confused:

Before you go testing sensors and fans...
Check your relays!!!

I swapped my relays (just to test it) & found that the relay that kicks in the fan when the temp sensor goes off was gone.
Was as simple as that, just pop open your relay box under the bonnet, change the aircon fan relay (as u know that works :P) & put it in place of the other relay.

Worked perfectly for me, thats where I'd start looking.

I'll scan the wiring docos for you 2nite..but that wont be till about 9pm...

to the bloke who suggested i swap relays, it's a damn good idea and was one of the first things i did. The fan relay worked in the A/C circuit, I should have mentioned this in the original post. I just don't have a wiring diagram for a TR, if i did i would be able to isolate the fault.

i can't realy remember but i think that the fans kick in when the temp of the water is sitting at about 91 degs. i wouldn't realy worry, mine sits just above half way too.....

The normal needle reading for the temperature guage is in the middle. If it goes above the middle during normal driving, I'd suggest you'd do some checking.

Oh and I found i was wrong about the A/C fan, i noticed it kicked in at the same time as the normal fan this afternoon after driving for about an hour.

I did not bother reading all the replies and this may have been covered.

If you are in doubt of your engine temp get a thermometer and check it in the radiator tobe sure.

95% of fan problems are caused by the relay, I had a guy come over a few months ago with a TR who had purchased new relays and even one of them was faulty.

Get a relay you know works, ie of the air con and swap it