100 series 1hz air con cutting out

Jacent,

The motor is getting too hot.
The 1HZ has a thermial cut off switch which is near the top raditor hose on the right hand side of the block.

When the motor cools the air con will work again.


Wayne

Wayne is right. Same thing happened to me. $400 later and a larger radiator..car runs cool and air-con purrs all the time. 1hz needs a larger radiator with aftermarket turbo when towing or running higher speeds.
cheers

Yes had the same problem with a troopy towing the 500kg camper in hot weather, also had it on the first trip with the then new troopy, the goose that fitted the dual battery system tied the wiring harness to that same temp sensor (on the passengers side near the top radiator hose) to the battery bracket and it eventually snapped the wires inside the insulation as it was being stretched by the engine movement. Took me ages to find it in the van park in Darwin.

Had the same problem on my 80 series with 1HZ, went through the whole radiator flush exercise without success, it was the fan clutch. a quick top up of silicone fluid and i havent had the problem again after 10 years.

Jacent,
You are over heating, a standard 1 HZ does this as well without the turbo.
It becomes common as the km's climb.
Toyota only gives you a cooling system just barely adequate for normal operations with a normally aspirated engine, adding a turbo adds alot of heat while towing.
The standard temp guage might not show much more than a needle width higher than normal.
Look at changing the thermostat, mine was only opening 50%.
The next item will be the viscous fan coupling, if yours is a toyota one you might get away with adding some silicone oil to it;
This bloke gives a good blog on it;
http://neuralfibre.com/paul/4wd/tuning-and-understanding-your-toyota-viscous-fan-clutch
or replace it with a new one.
I found the std radiator marginal while towing in QLD with the standard 1 HZ so I went for a 3 core copper unit, adding the heat load from the turbo will also require added cooling capacity.
The addition of an intercooler to the 1 HZ is also highly recommended on other forums, not so you can up the boost, but to cool the inlet charge as much as possible and lessen the heat load.
9 psi is also a recommended maximum, although others will disagree.
Water pump would also be on the list if your over 160,000 km or near a timing belt change.
If you dont have them EGT and boost guage s are a good idea for controling tempuature through right foot variation, keep the egts under 500deg C
And lastly a TM2 water temp guage is a good idea and cheap insurance, it WILL let you know temps are climbing before the standard guage even starts to move..

As stated I had thesame problem I put extra oil in the fan hub...no difference. The local toyota mechanic , whom I trust, told me that fitting an aftermarket turbo will definately require a "tropical radiator'. Lot thicker than the standard one.
DONT waste your time trying to do it cheaply. A new radiator, belts, water pump, thermostatcost bugger all. Maybe a $1000 all fitted..Should be way less. If ya can do it yourself...easy. I did mine.
As someone else stated...the standard 1hz motor only just keeps the engine cool enough now...the turbo adds a lot more heat

If you're planning of replacing a whole lot of parts just be aware that there is a lot of aftermarket stuff for 1Hz's that is nowhere near as good as genuine.

Genuine thermostats are cheaper than aftermarket - cost about $35 from Toyota - and genuine hoses and belts are same price as aftermarket.

Radiator flushes are a waste of money - better pulling it out and rodding the core. We had a good radiator specialist remove the top tank and rodded the core of an 80series and never looked back. Also if the plastic top tank might need replacing if its discoloured and becoming brittle. I personally prefer to do this than to buy a new aftermarket radiator which often don't last very long.
And there were a lot of people on LCOOL who had problems with aftermarket viscous fans on 1Hz. IMO, top up the genuine one with Toyota's silicon fluid.

And don't forget the common thing that gets missed by DIY mechanics - mud and rubbish in the air cond condensor preventing air flow into the radiator.

Worth fitting a Engine Watchdog TM2 so you're measuring the temperature properly. The factory temp gauge doesn't rise until its just about to overheat - it reads in the same spot in the middle of the gauge between 50 and 95 degrees C. The 1Hz will run at 76-85 degrees on the TM2 when the engine and cooling system are good.

Overheating seems to be a common question on 1Hz's with aftermarket turbos - hope yours gets easily sorted.