[GraphicX]

i'm doing a search atm on here to help troubleshoot, 28 pages long lol.

but yeah my G13BB jimny has started to overheat now, only since towing a camper trailer on the highway which was too heavy for it.

it's still only overheating on the highway, anything over about 85 & the temp will start to climb. also when temperature hits two thirds it's impossible to exceed about 105kph, even down hill with foot to the floor (is this a limp mode of sorts ?).

so far i've checked;

oil & coolant - both nice & clean
ran engine with radiator cap off - no bubbles at all & can see when thermostat opens (coolant level rises, shouldn't it fall ??)
no loss of coolant at all

could it be related to a faulty O2 sensor ? it's using more fuel than i think it should & when i initially drive off it wants to conk out & splutter before it has any power to drive off (kinda like a carby engine with the choke on & the engine is cold).

will be continuing my search here on the forum, but anything else i should be checking as to the cause ? could i have possibly just softened the head or something from when i towed the camper trailer (never exceeded two thirds on the temp gauge) ?

thanks for any help, just about got my funds together for a couple of mods & now i feel like i'm looking at a repair bill instead.

[atari4x4]

if it's not chucking custard in the rocker cover & your not losing coolant i think you might be right

first point of call would be the viscous clutch on the fan, have a suss in good tech for christover's diy recon, that & get your radiator rodded if it's still visually in good condition.

the fan should have a fair bit of "drive" once up to operating temp... i'd say the oil inside is done.

[GraphicX]

i've got that thread about the viscous fan oil open atm lol, looking over it so will have to give that a go.

i've had another radiator done in the past where they cleaned the channels, think it was about $150, the radiator looks good from the outside so maybe it's worth getting the reconditioning done as you've said.

[atari4x4]

new one wouldn't be much more from 4wd parts, saves having it off the road for any length of time... pull the rad flush it, new genuine thermostat with the bleed nipple snipped off & fresh coolant & either reco the fan hub or pick up a replacement & reco the original one when you get a chance & keep it as a spare.

[GraphicX]

been reading about here a ton about others having the overheating issues, seems those aluminum radiators aren't too bad (always thought aluminum was pretty bad a dissipating heat compared to copper though). like you said it may be better just replacing it & that way it's only off the road for a day & i can swap it out myself.