Outer Limits 4x4 Board

If anyone has a turbo'd 1HZ I'd love your feedback.

Mine (running boost TBA and EGT tba - gauges on order) with an AXT kit gets hot if I push it too hard. It's fine on the highway even with a trailer, and up hills without a trailer.
When I put 3ton behind it however, and then take on a range I have to back off to 50% throttle max. Any more and the temp creeps up to red. Holding the trans in a lower gear helps somewhat at keeping it on 3/4. It strange as I can hold more than 50% throttle unladen, but when heavily loaded it doesn't like it. This is the Toowoomba range at night in winter so ambient below 10deg (nearly 5) and AC is off.
Low speed tooling round forests etc is never a problem, even in sticky mud. I havn't tried sand *yet*. Even steep long climbs are fine at low speed low range, so fan is pulling air ok.

Radiator is clean and recently stripped. Viscous clutch has been replaced. Coolant etc are up to spec, it's not boiling over. Radiator cap is holding pressure and recovering fine. Water pump is unknown, but no noise or leaks. High speed, high throttle is fine, so no probs with natural airlfow from lights, bullbar etc. I haven't changed the thermostat, but operation seems perfect. Fast warm up and very stable temp hold at 50% regardless of outside conditions.

From what I see all the diesels use the same radiator, although I did see a reference to an update around '02 that changed the pitch and fins to increase efficiency.

Mine is an auto and has the huge front factory trans cooler. I have also added a trans cooler into the bottom tank of the radiator where the factory one would go (mine didn't have one for some reason).

This behaviour has been constant since I have owned the car.

I am working on the assumption that it is either
a) The indirect injection head really is that much less efficient and soaks up too much heat
b) the fueling is over the top - need an EGT to confirm / deny
c) There is a better radiator out there on the factory 1HD-FT's
d) This normal and most ppl dont flog their cars on ranges enough to find out.

The only other hint I have is that on the old 60 series it was very evident when the vicous can clutched in an out from the noise. I assume the raditor was happy with passivve airflow much of the time. On this car, even with the new clutch, the fan seems coupled most of the time, and is quite noisy. I dont know if this is due to a lower engagement setting on the clutch, or a higher waste air temp from the raditor.

Thanx
Paul

Hi,

I can only speak from my experience with the 80 series, 1hz with axt turbo fitted roughly 6 months ago. When I had first bought the car about 6 years ago it had the occasional heat up with no apparent reason. I traced it back to the viscous and since changing it, everything has been fine. I have since changed the radiator as the original one was slightly leaking/sweating from the o-rings/seal around the crappy plastic tanks. I replaced it with a full metal unit from repco. The radiator guy reckons they do get blockages through the channels and are sometimes hard to detect, and with resealing the plastic tank not being a sure thing, I changed the whole thing.

Now, since the turbo, I did fit an EGT gauge and have got the expected results. Just the car itself, full throttle in 4th can get the temp close to 400 degrees, and towing around 2.5 tonnes, this climbs up to 480. With a thermo (infra red gun style) it was found my gauge is reading 30 degrees hotter. That doesn't worry me as long as its not reading lower.

The temp gauge does not move from half. It actually sits about half a mm on a slight tilt under half under all conditions. I've used the a/cond occasionally and not noticed any difference but I will know more in summer. So far so good.

So I believe your problem could relate to tuning and fuel. Get an EGT fitted and get the car on a dyno with someone who knows diesels. it shouldn't be overheating and you don't want to cause any damage/$$$.

is there anything on your bullbar obstructing air flow? Hows your thermostat?

I would coment bout my experience turboing my 2H ..

The Pyro gauge it's a must .. just to know if really your factury temp gauge it's working fine .. in my experience thosse gauges ( the factory ones ) have many flat spots .. and I didn't really liked ..

just in order to be sure that all it's safe get EGT and water mechanical gauges ..

Sometimes I saw it in my 60 when I come out from a trail .. in the HW the temp come close to 1/2 when usualy are in 1/4, after some runs clean, weeks after the trail all come to the normality HW or city driving ..

I haev a 1hz witha dts turbo on it, running 13lb max, my egt can climb all the way to 550 degrees and the water temp stays on half, if it is tuned correctly it should have no heating issues. If you are driving up a range with 3 ton on board with no pyro you are asking for trouble, without a boost gauge and pyro you hav no idea whats happening to that motor.

Paul

1HZ with factory 1HDT CT26 turbo fitted with top-mount WRX
Intercooler. I can get my pyrometer to 550 deg. no prob by
accelerating hard onto the highway and all the time the factory
temp gauge will NEVER move. (its only gone up once after I
filled it with mud and tried to drive home, doh!!!)

Remember temp. problems is a compounding problem, eg. the
longer the hill the more it will heat up, you will be quite suprised
(probably horrified) how easily you can get them really hot and
your factory temp gauge doesnt move.
Dropping back to 4th or 3rd like you would of had to do before
it was turboed will help heaps, it will rev real hard and sound
like your thrashing it but your pyro will show its working less.

Your cooling system is probably fine if its not heating up under
normal driving (ie, not towing 3 tonnes) you probably just need to
alter your driving were need be. That Toowoomba range is
a killer, I used to live near there.

Put new oil in the clutch fan....or get a elctric fan up front and see if that fixes it then put oil in....

chpd 80 wrote: you will be quite suprised
(probably horrified) how easily you can get them really hot and
your factory temp gauge doesnt move.

This it'sa fact .. I never trust in factory gauges .. actually I thought they gve to you an overall idea bout the situation .. but don't spect accuracy readings ..

dow50r wrote:Put new oil in the clutch fan....or get a elctric fan up front and see if that fixes it then put oil in....

Agree with Andrew - first thing I would look at it is the fan clutch - do you have a mates clutch you can borrow? I have seen on the odd occasion a new one bodgy from the word go. Do a search for "fan AND clutch" in the Toyota section for more info.

Good luck and let us know how you go.

Cheers

But you have problems in HW or in traffic .. ?

Coz if you have problems at low speeds ej traffic on the town, the fan clutch it's an option .. but when you are running hi speed HW, the air throught th rad it's more than the fan can pull .. so the fan cluctch it's fresh and not complete engaged anycase ..

So the guys with 550 deg C on the EGT probe, is the probe before or after the turbo?

Mine is in the dump pipe after the turbo.

I know I know, its better to have it in the manifold before
the turbo. I'll get round to moving it one day.

KiwiBacon wrote:So the guys with 550 deg C on the EGT probe, is the probe before or after the turbo?

Mine is also after the turbo. I have never had it over 500 and my gauge reads 30 degrees higher than the actual. That was with 2.5tonnes of caravan, slight incline and flat to the floor in third then fourth.

Based on diferent turbos and % Eficience .. are a 200 - 300 F drop temp before and after turbo ..

mine ..

You guys with turbo'd 1HZ's and EGT guages fitted post turbo are asking for trouble.

The heat kills the engine/pistons long before it hurts the turbo.

You should be concerned about the combustion temps.. not whats happening down the dump pipe...

I have my probe fitted in the exhaust manifold between number 5 and
6 cylinder, I run 7 psi max boost, no soot under acceleration, and on a long climb can make 600 degrees pretty easy...