Fluctuating temp gauge

[Don Logan]

Hello, i left my truck round my mates for about 10 weeks over jan-march. He drove it round the block occasionally to keep things runnning over. I picked it up a couple of weeks ago and drove 80 miles on the motorway. About 30 miles into the trip, the temp gauge started fluctuating between halfway and just bordering on red. I stopped, let it cool, put some coolant in and carried on. After a while the gauge stayed mainly normal at halfway, but would often creep up to 3/4 and then drop back down again.

Does anyone have any idea if this problem could be linked to letting the truck stay undriven for a long time? It's not losing coolant and i had the head tested not long ago. I thought that maybe it could have just been an airlock, possibly caused by letting it sit (in freezing temperatures) for so long?

Yesterday i changed the themostat and burped the cooling system. Then i took it for a drive and it seemed ok. It ran fine with the temp at halfway as it normally does.

When should the small fan in front of the radiator kick in? I can pour hot water over the sensor to test it can't i? Anyone know where it is?

The truck has recently had a new radiator and now has had a new stat. Are there any other parts of the cooling system i can renew or test to be on the safe side?

Cheers.

[darkdezigns]

change yr rap cap,then run till fan comes on,mine comes on bout 3/4 heat

[Don Logan]

Yeah, i changed the rad cap, but can't get it to 3/4 heat to test the fan. Suppose that's a good thing though...

Where's the fan temp switch/sensor?

I take it you meant rad cap and not rap cap?

[darkdezigns]

Yeah, i changed the rad cap, but can't get it to 3/4 heat to test the fan. Suppose that's a good thing though...

Where's the fan temp switch/sensor?

I take it you meant rad cap and not rap cap?

lmao rad cap yes,tbh not need to find sensor on mine yet but i wouldnt think its difficult to find,id look for the sensor near the stat,and if it wont get hot enough to get to that temp i'd say a good thing

[Scorpion]

I take it you meant rad cap and not rap cap?

No he definitely meant one of these cause it helps to keep you looking 'cool'!




Seriously though, if you have recently had a new radiator etc fitted there may still be air in the system causing the fluctuation. Try 'burping' the system again, there are some great write ups on here somewhere.

Here's a link to one of the threads.

http://www.hiluxsurf.co.uk/forums/sh...hlight=burping

[darkdezigns]

No he definitely meant one of these cause it helps to keep you looking 'cool'!



Seriously though, if you have recently had a new radiator etc fitted there may still be air in the system causing the fluctuation. Try 'burping' the system again, there are some great write ups on here somewhere.

Here's a link to one of the threads.

http://www.hiluxsurf.co.uk/forums/sh...hlight=burping

anythings better than driving a bm

[Scorpion]

anythings better than driving a bm

Now, now, jealousy will get you nowhere!

[Don Logan]

Cheers. Reckon it was an airlock then? Anyone know about testing the fan in front of the rad to make sure it's working?

[MattF]

The truck has recently had a new radiator and now has had a new stat. Are there any other parts of the cooling system i can renew or test to be on the safe side?

Keep checking and topping up the coolant, (if necessary), over the next week or two and keep an eye on the gauge. By the sounds of it, you hadn't purged the air out of the system completely.

[BUSHWHACKER]

Cheers. Reckon it was an airlock then? Anyone know about testing the fan in front of the rad to make sure it's working?

Ignition on, pull the wire off the sender and the fan should come on.

[GRASSMAN]

Cheers. Reckon it was an airlock then? Anyone know about testing the fan in front of the rad to make sure it's working?

Hi Don,

On the 2.4's the fans sensor fails safe, disconnect the connector
for the fan at the stat housing, turn on the ignition, and the
fan will start. The fan temp sensor is over £50.00. Not sure about
the 3l tho. Try a multi meter and boiling water to test the sensor,
be carefull.
Hope this helps.

Gman.

[POPEYE]

The sensor on 2.4's cuts in at around 98-100 deg's 3lt may be the same, mine never ever cut in in two years, the corolla sensor fits and has a lower cut in of around 94d i think, but since moding my fans they comes on regularly,
if you have doubts about overheating i'd fit a aftermarket temp gauge, at least you can see exactly wots happening unlike the useless stock gauge, also modding the fans (i fitted an extra one) allows them to come on after the ign is off, mine useually fire up after i've parked showing that the temp does go up even after the engines stopped,

[The Lovely Boyo]

The sender is the little plug in the pic #6

I think?!?!? haha can't remember, old age, too much beer etc

http://toyotasurf.asn.au/techsite/24lteparts.htm

Lots of info

http://toyotasurf.asn.au/techsite/24table.htm

http://toyotasurf.asn.au/techsite/

[MattF]

It's a 3.0L. That front fan is for the aircon, not an aux fan as on the 2.4L, is it not?

[POPEYE]

It's a 3.0L. That front fan is for the aircon, not an aux fan as on the 2.4L, is it not?

Seem to remember someone metioning that but surly for a back up fan to help cool the rad it'd need to be in front (or behind) the rad? or is the aircon rad in front of the main rad on 3lt's? dunno