100 series 1hz air con cutting out

Submitted: Wednesday, May 09, 2012 at 03:52
ThreadID: 95448 Views:12004 Replies:7 FollowUps:15
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Has anyone else ever have their air con cut out in a 100 series with the 1 hz motor?
It has aftermarket turbo, air con cuts in and out out on hot days when sitting on a 100kms, even more when towing.. I tow in 4th at around 90kms, van weighs 1650kgs. Turbo was set up on dyno by MTQ. Any suggestions as to why or is this just a common problem?
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Reply By: Wayne (NSW) - Wednesday, May 09, 2012 at 05:15

Wednesday, May 09, 2012 at 05:15

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.

AnswerID: 485326

Reply By: Bigfish - Wednesday, May 09, 2012 at 05:30

Wednesday, May 09, 2012 at 05:30
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.
AnswerID: 485327

Follow Up By: jacent - Wednesday, May 09, 2012 at 07:56

Wednesday, May 09, 2012 at 07:56
cheers mate, after this happened a few times I had my radiator flushed and all the coolant replaced but this made no difference, so fitting a larger radiator sounds like the go! do you have any specs on the size of radiator or brand you got fitted?
I def want to get this sorted as its a great fourby with that little annoying air con issue!
FollowupID: 760580

Follow Up By: olcoolone - Wednesday, May 09, 2012 at 09:47

Wednesday, May 09, 2012 at 09:47
Before spending money on a new radiator you also might want the check the viscous engine fan..... over time they become lazy, the other thing is you can adjust the cut in temp and slippage.

Simple thing to repair and should cost you about $15 for the viscous fan fluid and a few hours work.

We do a few of theses through our workshop.
FollowupID: 760590

Follow Up By: Member - Joe n Mel n kids (FNQ - Wednesday, May 09, 2012 at 10:08

Wednesday, May 09, 2012 at 10:08
Yep had same problem, bite the bullet and replace it all as it is a LOT cheaper than a blown motor and towing from the middle of noware ....... do the radiator, NEW viscous clutch (DONT bother trying to re-fill it), new belts, new hoses, new water pump and new thermostat ......
I spent probally a full year slowerly replacing it all until i finally got it right, i did the silicone replacement thing and yes it worked for a while but leaked out, cheaper in the long run to buy a new unit as you then have NEW seals and it wont leak out, also buy a gen toyota hub, dont buy a cheapy, do the pump even if it is not old, you wil have the radiator, belts ect out so the job is already started and yes it will cost a bleep eload but a bleep eload cheaper than blowing up your motor with overheating .......
FollowupID: 760592

Follow Up By: Rockape - Wednesday, May 09, 2012 at 16:39

Wednesday, May 09, 2012 at 16:39
I second Joe and Mels answer on the viscous hub. If you are going to buy get the genuine one.

Also I like the genuine radiators as they are made by Nippon Denso.

Tried a few things with my 75 series cruiser fitted with a 6.5l chev diesel. It used to get hot before I changed to the chev and that did the same, not bad mind you but enough to cause concern and the watching of the temp gauge all the time. Remember the 75 series have a small frontal area and the same goes for the engine bay.

In the end I fitted a genuine radiator for a 1HD-FT engined cruiser and all problems were solved. It now never even looks like getting hot.

FollowupID: 760613

Follow Up By: olcoolone - Wednesday, May 09, 2012 at 16:57

Wednesday, May 09, 2012 at 16:57
Most of the fan hubs we rebuild don't have a leak, we find over the years the viscous fluid goes off and when they are new they are set for the average joe's driving habits with a big emphasis on fuel economy and quietness.

If someone does a lot of slower driving like off road, tow a van or carry a heavy weight the fan doesn't cut it.

We clean the viscous coupling out add about 40% more then factory and reset the spring to cut in a bit sooner and allow more lockup.

FollowupID: 760614

Reply By: Ozhumvee - Wednesday, May 09, 2012 at 06:41

Wednesday, May 09, 2012 at 06:41
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.
AnswerID: 485330

Follow Up By: jacent - Wednesday, May 09, 2012 at 08:00

Wednesday, May 09, 2012 at 08:00
The old saying I guess, common sense aint that common! cheers

FollowupID: 760581

Follow Up By: jacent - Wednesday, May 09, 2012 at 08:04

Wednesday, May 09, 2012 at 08:04
Might take it down to geraldton, can anyone recommend a radiator specialist in geraldton? natrad?
FollowupID: 760582

Reply By: Ruffstuff - Wednesday, May 09, 2012 at 09:21

Wednesday, May 09, 2012 at 09:21
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.
AnswerID: 485340

Follow Up By: jacent - Wednesday, May 09, 2012 at 09:44

Wednesday, May 09, 2012 at 09:44
Oh ok I'm pretty handy how would I go about topping up the fan clutch?I will try this before up grading radiator! Cheers!
FollowupID: 760589

Follow Up By: Member - Joe n Mel n kids (FNQ - Wednesday, May 09, 2012 at 10:11

Wednesday, May 09, 2012 at 10:11
go to the LCOOL site from memory and they have a detailed write up but remember you are only replacing the fluid not the seals, it leaked out because of the seals, some have been lucky as above but many have ended up buying new hubs in the long run ....
FollowupID: 760593

Follow Up By: Ruffstuff - Wednesday, May 09, 2012 at 10:32

Wednesday, May 09, 2012 at 10:32
My fan clutch wasnt actually pulled apart, it was drilled and tapped.
FollowupID: 760595

Reply By: guzzi - Wednesday, May 09, 2012 at 10:56

Wednesday, May 09, 2012 at 10:56
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;
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..
AnswerID: 485343

Follow Up By: jacent - Wednesday, May 09, 2012 at 21:10

Wednesday, May 09, 2012 at 21:10
Thanks for all your information, will do all of above, car has done 270,000 now so prob time for an oveahaul on the cooling system! I wont bother mucking around with the fan hub, will just get a newie from toyota & fit it and eliminate that all together, along with a thermostat, guages and radiator, missus hates when I got to spare parts shops cos I have free run on the bank account!
FollowupID: 760642

Reply By: Bigfish - Wednesday, May 09, 2012 at 12:26

Wednesday, May 09, 2012 at 12:26
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
AnswerID: 485347

Follow Up By: Member - Andrew L (QLD) - Wednesday, May 09, 2012 at 15:11

Wednesday, May 09, 2012 at 15:11
"the turbo adds a lot more heat"

Its not the turbo that adds a lot more heat, it is the extra fueling being provided by the adjusted fuel pump, being inefficiently burn't within the indirect injection combustion chambers and a lot of the fuel energy ending up as heat soak and not KW's at the wheels.

The 1HZ is a great N/A engine, but for positive pressure inlet and mechanical injection extra fuel it is not the right injection and combustion chamber design to be efficient or long lasting.
FollowupID: 760610

Reply By: Member - Phil G (SA) - Wednesday, May 09, 2012 at 16:23

Wednesday, May 09, 2012 at 16:23
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.
AnswerID: 485357

Follow Up By: jacent - Wednesday, May 09, 2012 at 20:59

Wednesday, May 09, 2012 at 20:59
thanks for all the advice! I live in a remote town in the northern goldfields w.a, so will have to plan a trip to kalgoorlie or geraldton and pick myself up some genuine parts!
I rarely have access to a mechanic who knows what they are doing, so need to tackle most things myself! I will definately get myself an egt, boost and temp guage as it sounds like the toyota ones aren't too crash hot! W ill do the thermostat, fan hub and get the radiator rodded and fingers crossed. Have been interested about a top mount intercooler and its something I may also fit! Cheers
FollowupID: 760638

Follow Up By: Lunarite - Thursday, May 10, 2012 at 14:02

Thursday, May 10, 2012 at 14:02
Don't rule out the aircon itself.
I recently had my aircon cutting out after a 2-3 hr drive in warmish conditions, took it in for a service and was informed that the evaporator was leaking.
FollowupID: 760702

Follow Up By: jacent - Sunday, Jun 03, 2012 at 04:53

Sunday, Jun 03, 2012 at 04:53
Thanks for all the replies! Its booked in to get new swivel hub seals and bearings on wednesday so will get a new toyota thermostat and viscous fan replaced at the same time! I read on another forum that if the radiator cap is on ots way out it can also contribute to the issue, so willl replace that as well! if I still have issues I will do the tropical radiator next then water pump
FollowupID: 762740

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