Hey guys

Recently bought my girlfriend a TL Magna, and its been awesome to drive

But I went to pick her up from work and ended up sitting in a queue of traffic for probably 15 minutes, temperature creeped up to about 3/4 of the way up, thankfully we started moving again and it went back down to just under halfway where it stayed for the rest of the trip home.

I couldn't get out to check the thermo fan when it was getting really warm; the air con fan works fine and I changed a few relays around (swapped the two air con ones with the two fan ones), air con fan still works but i havent been able to make the thermo fan come on while the car just sits in my driveway (although I would have only had it idling for about 3 or 4 minutes).

So, few questions:

1. How can I diagnose this problem? The coolant system is full and completely pressurised, no leaks at all.

2. If it is a faulty relay (although seems unlikely), where can I even buy new relays from?

3. What else could the issue be?

This was the first time in a week of owning and driving it around that I saw the temp gauge go over just under halfway, quite concerning. :(

I'd be concerned too!....from the looks of it the problem should not be expensive to fix...probably either a fuse blown or the coolant temperature sensor (not the temp gauge one). You should download the free workshop manual....I'll put the address below - it has all the wiring diagrams plus how to test sensors etc. Good Luck.
http://www.lisho.net/?page_id=3

Edit - had a look at the wiring diagram - section 54C Cooling System....indicates a 40amp fusible link and a 20amp dedicated fuse (number 8 automatic A/C, cooling)....so hopefully it will be the 20amp fuse.

fiddled with more of the fan relays and turns out one of them had a really wobbly pin that was pushed in a bit, swapped it with an air con relay and when the car sits in idle i can see the radiator fan comes on and turns off in the space of maybe 30 second intervals (while sitting in my driveway from a cold start).

curiously now that one of the air con relays is now missing the air con still works but the air con fan only spins when the radiator fan spins; i should really organise for another relay to replace the one ive 'borrowed'. Where can I get them from - is a mitsubishi dealer the only way?

A self serve wreckers is a good place to start. Take the old one with you to make sure you get one with the right amp rating/pin configuration.

Cheers

. . . . and turns out one of them had a really wobbly pin that was pushed in a bit . . . . .

Usually caused by excess heat inside the relay melting the material the pin sits in. Classic failure, junk it. As suggested, grab a few with the same rating from a wreckers. Grab a handful of fuses too. lol

thanks for the help guys. :D it is a nice day today to head to one of the many wreckers down south of adelaide but i ended up just going to repco and getting a suitable NARVA replacement for $8. to be safe i moved the power window relay to the fan relay slot (fan comes on no worries now after about a minute of sitting idle) and put the NARVA relay in the power window socket; all the power windows work and the fan comes on so id say thats one mystery solved for the day. :)

i have a whole box of fuses of different values and sizes thanks to an older car (ford mondeo) that had like 6 blown fuses...i didnt kep that car for long, but the full box of fuses is still with me.

next problem to work out is why the horn doesn't work...but thats a problem for another day (unless anyone can give me any hints; there does not appear to be a horn fuse - manual says it doesnt need one, and the horn relay is in place and doesnt appear to be damaged at all).

With the horn, it's a common problem on these cars
Had to get mine replaced under warranty when it stop working, rho i'm not sure what they actually replaced

As for the overheating, might wanna check to see if you have a sticky thermostat
Wanna make sure its opening and closing when its ment to
When the fans turn on do they both turn on or only one?
Because one of the fans will turn on once the a/c is turned on

the AC fan (one closest to the drivers side of the car) comes on and turns off when you turn the AC on and off

before i did the relay shuffle-around i never saw the thermo fan come on at all, but now ive seen (and heard) it come on while idling, both in my driveway and at a longer set of traffic lights today (when sitting in a clump of traffic).

i will make sure my girlfriend keeps an eye on the temp gauge over the next week though for further analysis, unfortunately its cold weather all week and she doesnt drive in traffic much so might be hard to replicate the same conditions as on saturday

Also, just a thought, but could the thermostat be jammed in an opened or closed position? Once my car overheadted and it was the thermostat that was closed and wouldn't open. It was a $10 part and a quick change and she was away, good as gold.

Also, I educated my wife many years ago that the car will always sit on half way, from the day it rolled off the production line till today. If ever, and I mean ever, it gets over half way, then stop on the side of the road and call me. Continue driving and it could overheat. Around 3 years ago, this actually happened. She stopped, pulled over and I get there, no water in the radiator. Fearing the worst, I drove it home, the next day empty again. Diagnosis was a leaky radiator top tank and a water pump too. So fixed it and all new. The message is, continue to drive and risk damage, so always stop and be safe. I've had so many mechanics say the gauges move around to 3/4 on a hot day. I said BS mate, on a hot day with the AC on, the car always ran colder, due to twin fans going like mad. It was actually the opposite. I know my car and watched that gauge never move for 14 years, and today it moved and you Mr Mechanic said its normal. Maybe in a holden, but not a Toyota that I had at the time. :)

I will back that up. All my Magnas (TS 2.6, TS 3.0, TJ 3.5) have been stable in the temp gauge, sitting in the middle when warmed up, no matter what. Air con on, 45 degree day, shuffling through McD's drive through or stuck in traffic, to high speed open road, always very stable. If it moves above that, I know something is wrong. Simple as that.