over heating 1hz 80 series

Do u have a vibration flex joint on the exhaust pipe still?? sometimes the baffle in the muffler can rattle loose if you take it off.then the exhaust cant get out and heat stays in

tony

is the new radiator you had fitted a standard replacement or larger? assuming there is no internal problem with the engine you may need a larger one

cheers

You say you have a new Viscous fan hub, does this mean you have squeezed more silicone in there than standard or just put a new hub on? Reason I ask, is my old 1HZ 100 series required the addittion of 3 tubes of silicone into the hub which then fixed my overheating issue I had with this truck (only happened for one hot week in Tamworth but silicone in hub solved it anyway).

Other thing to check would be thermostat??

Hope it helps.
Trevor.

I run the DTS unit on my 1HZ and the most it will go under extreme load is 3/4 on the guage and when you are off load (down hill) it will drop back to 1/3 which is where it normally runs. Maybe suss out that its not leaning under load, do you ever see any black smoke in the lights behind you?. Hope this helps.

Have you asked Safari? If this is a common problem when their kits are fitted to your model then they should be aware of it and have an answer.

I have never fitted an aftermarket turbo to anything so I am wondering if you have done anything to the fuel sytem. A turbo will force more air in so I would imagine it will need more fuel otherwise it will be too lean and this will increase the temperature.

Years ago I fitted straight LPG to a Gemini that I wanted to use as a high mileage commuter car to and from work. The car was in excellent condition but immediately started getting hot when the gas went in. A new triple core radiator and a bit of fiddling around with gas mixtures, thermostats and ignition timing made no difference. I removed the radiator and built a fiberglass fan shroud directly on it. It bolted on with a glove like fit and came in as close as possible around the fan. It fixed the problem immediately and the car went on for another 180,000 ks without any problems.

I don't know if you have a shroud or not but you may have to consider one if you don't.

Brian

Tony,

my previous Cruiser was an 80 with exactly that problem:

going up a steady incline the needle would go into the red and then drop when I backed off or when going down the other side of the hill.

The under oiled viscous hub was a contributor but the cause:

the radiator hoses were old and soft and the lower, in particular, would suck itself thin when going up the hill and then relax when I backed off.

I replaced both hoses and the problem disappeared.

However I also had suspicions about the large Safari intercooler in front of the radiator.

But the new hoses were the answer.

Wish I could suck myself thin !!

Tony,

Worth checking the temp with a quality aftermarket gauge to get a real idea of what is going on. With the older 2H engines the temp sender tends to become more sensitive with age, not sure about the 1HZ. Perhaps look at restrictions to airflow such as intercoolers, lights, oil and transmission coolers etc.

I also had overheating problems recently in 1Hz. Had radiator checked (clear), replaced hub (made no difference), replaced thermostat - problem solved. Would have been much cheaper for me if I'd done the investigation in the order recommended in the manual (thermostat first!)

Hi Tony,

I've just finished fitting a turbo to my 1HZ in a 100series. Have you got an EGT gauge fitted which is telling you your not going over 550 deg C or are you taking the word of the installer??

If you haven't got one fitted I'd get an EGT gauge asap (I just bought one from USA for $150) and see what the actual temp is. I towed my camper (admittedly probably not as heavy as you boat) all the way to Brisbane and back last month and the only place the temp needle moved was trying to go up the Toowoomba range in 3rd. Stayed in 2nd and no probs.

I haven't touched my cooling system at all, before or since turbo installation and my vehicle has 270000km.

If its still overheating after doing all the things you've done I reckon its being overfueled and could be doing substantial damage to the engine cylinders.

The other thing to check is flow thru the radiator - do you have big spotlights, a winch and bug screen blocking flow?? Try removing these and see what happens cause thats all stiffening up your viscous hub is going to do (by adding more silicon)....suck more air thru radiator.

Good luck - these sorts of problems can be a real bitch to fix.

I think the standard radiator is a 2-core. We have a 3-core option in our 1hz vehicle- and towing nearly 2 tonne of trailer sailer up Macquarie Pass or Mount Ousley on a hot summer day- NO over heating probs...
Will be fitting an EGT gauge very shortly ...

Do you mean your coolant in cooling system get too hot, ot it is just EGT?
Serg

Tony,

all comments here are constructive but if your hoses are old, they will be the problem.

I replaced EVERYTHING, radiator included and the issue persisted until I replaced the hoses.

Tony,

I went through all this with a 2H with aftermarket Turbo Replaced everything bar the Sender. Guess what the Sender had fallen to pieces. Now never goes over 1/4 on the hottest day. For the cost of a Sender try it !

Run the engine until it's warm, lift up the bonnet and open the throttle or run the revs up a bit to where you think you would be pulling a load.
Keep an eye on the top and bottom radiator hoses and make sure that one or the other is not being sucked closed.

If it is, get some wire from a coat hanger and wind it around a bit of 25 to 30mm pipe like a coil and stretch it out until it is long enough to fit inside the hose.

G'day Tony. Mate I was having the same dramas with my Patrol for about a year. I went through the system from front to back with limited success. Every expert had a different reason from cracked head through to radiator cap. In my case it was the plastic header bottle, it had a hair line crack which didn't allow the system to get up to full pressure. But only in high load situations. So when they did pressure tests it kept coming up fine. It drove me crazy. I was so close to either putting a bullet through my head or torching the bloody car!!!! GOOD LUCK and I really hope you get to the bottom of the problem.

Cheers Stefan

Get a head test done. There are these paper strips like litmus paper that you dip into the radiator fluid and it tells you if there is a problem like a warped head.

When did the problem arise - was it after something major was done or ?????

I would suggest you have a look at all the ancillary hoses on the vehicle like the thermo wax pipe (runs between the engine and injector pump), the water cooling for the turbo and the other non genuine bits to do with the turbo installation.

Generally speaking the Toyota cooling system is over capacity and copes easily with turbo and non turbo installs. FWIW the factory turbo uses the same rad as the 1HZ which tells you a lot.

Only time I had a cooling problem was after a Levuka trip - the lower core was blocked with mud. Only found it when I pulled the rad to get at the viscous coupling.