Outer Limits 4x4 Board

Hey All

my 12HT to me is gutless in comparrison to my mums Stock 1HD-T I know they are alot quicker motor, But it honestly runs rings around mine. I have a 3" Exhaust, K&N Air filter And Snorkel, My boost guage reads 9 PSI under full boost, so im not sure if it is running lean! When driving on the highway at 110Km'h the temp gauge will climb to just around the 3/4 mark where as though around town the guage sits on around 1/4 or a tiny bit above. It concerns me as im going up to fraser Island in january towing a trailer and will deffinetly have the air-con on, so im not sure how hot it will run.

I have disconected the Boost compensator vacuum line thing off the injector pump and took it for a drive and it made no difference what so ever, is that normal?

Is there anyone here on the south side of brizzy with a 12HT 60 series?

If anyone has any feedback or has a 12HT can they tell me if this behaviour is normal.

Cheers
Troy

vSAHARAx wrote:When driving on the highway at 110Km'h the temp gauge will climb to just around the 3/4 mark where as though around town the guage sits on around 1/4 or a tiny bit above.
Cheers
Troy

I reckon this'll be caused coz the clutch fan has shat. Either get the fluid that'll possibly fix it or get another clutch. I have just replaced my clutch after trying the fluid but the problem (110kmh gets hot) has gradully returned to the point where its dangerous. Oh and I have a 1HZ in an 80.
Jonesy

Troy
You have nailed the problem....if you disconnect the boost compensater and nothing happens, then there is a pump problem.
This however doesnt explain why its getting hot, less fuel on a diesel means less heat, completely opposite to the petrol. If i were you, id be looking at the fuel system from tank to pump for restrictions from algaie or crap. There is a filter in the tank suction line, and another at the pump inlet, check them both. Cut open the diesel main filter and if there is any green sludge, it is algaie and treat it....im thinking you have lack of fuel which puts timing out aswell as less fuel.
Its been a fair while sinse ive seen a 12h pump, but im not sure if your 12h has a boost compensator ike the hdt.
Andrew

Troy
the hdt is a quick motor compared to the 12h. Look around for an old electric fan and install that up front, if it makes a difference, change the oil in the clutch fan. It could also be a partially blocked radiator causing this, or even a partially closed thermistat, you need to do as much checking as you can b4 opening your wallet. My money is on the rad, but here is another thought, if you were wanting to boost the turbo up to 12 or so psi, fitting a pyrometer to the exhaust of the turbo would tell you if you have a fuel or cooling problem now by the heat coming out, aswell as assist in tuning when you turn it up.
Andrew

I thought at 110km/h the fan wouldn't really be doing anything as such, or am i wrong?

I have put a new radiator in (12 months ago), New Thermostat (6 months ago), New hoses and water pump (2 months ago). Could i take the thermostat out and run it for a week or so without it and see what happens? maybe the thermostat is a bit suss (though bought it from Toyota).

The 12HT's injector pump does have a boost compensator, How many fuel Filters are there on these trucks? I now know there is a primary filter in the lift pump, and of course the secondary filter that being the big cartridge one (that gets changed every 10 000K) What happens if a diesel runs lean?

Also if slowing down, say for example, im stopping at a "T" intersection and i press the clutch in when the motor is doing around 1500 rpm, returning to idle it revs below idle, all the dash lights flicker for a micro second then returns to idle, a couple of times it has just stalled on me, what could this be caused by????

Thanks for the help fellas please keep ur ideas coming!!!!

The extra info helps...your compensator is had it, or your fuel supply is blocked, and restricting fuel, if you can disconnect it and no difference, it probably isnt allowing extra injection.
The motor should run cool with new everything, check it is actually getting hot by putting a second cheap gauge in the radiator water...dont pull the thermistat...this is what i mean by check as much as possible.....all the bits you have bought might not have been needed and it might be the gauge...
If the pump is overfueling or injecting late, you will get excess heat from combustion, and hot motor...does the cruiser chew fuel or is it really good? Good means starving for fuel, bad means over injection, is there black smoke or white or blue, are your brakes binding, is the muffler collapsed inside because you havnt used a flex joint....you need to write down all these tell tales and get a prognosis from them..
Andrew

How many K's has the truck done, If the truck is high in mileage that can have a effect on how the temperature is. When you run the boost that you are running that can have the effect for higher temps when the engine is high in mileage. Don't take the thermostat out because that can have the reverse effect for trying get the engine cool, the water will bypass the radiator quicker, making it run hotter that way. How long a go did you get the injectors and pump overhauled, that could also be a problem for the lack of power. Try diesel Australia at Slacks Creek for getting a price on reco of the injectors and pump. they did a great job on my cruiser and were reasonable on price.

I Only found out they have a primary filter in the lift pump on sunday, i thought they only had the cartridge filter, but the primary filter is the filter it goes through first and i have never had a look at it .

i noticed oil coming from the vacuum line that connects to the compensator, is that normal?

I Have had alot of trouble with my temp gauge in the past, so it has a new genuine temp sender, the radiator had a leak so i got a new one, and the old thermostat was seized open.

The Cruiser uses around 13L/100k

Blows a dirty big puff on start up (when hot or cold), going by what i see in cars headlights behind me at night, one decent sized puff off the line when accelerating, then doesnt blow bugger all smoke until 2500rpm onwards, when up it for the rent (All Black Smoke = Fuel).

Whole Braking System has been totally re-done about 6 months ago so no issues there.

I Also have a 3.5" Dump pipe off the turbo into a 3" mendrel bent exhaust with no muffler or resonator, just a straight pipe

The Truck has just clicked over 358 500km's So i dont expect it to perform miracles

My Boost Guage is saying 9psi when under normal full boost, though i havnt touched the turbo so i think the waste gate actuator might be getting a bit lazy or something i thought they only put out 7psi stock

And ahhhhhhhh the injectors or pump have never been touched

All your feedback is great fellas plz keep it comming

Injecters are supposed to be done every 100k, and pump every 200, or there abouts...so u r on borrowed time....puf of smoke indicitive of these motors, because they get full fuel till they run. the extra boost is probably a rersult of the free flow exhaust....there is another filter in the tank....sounds like it is overfueling (black exhaust)and that will give you high temps...also could be retarded timing from algae blocking the fuel line filters (black smoke high load) economy isnt that bad.....problem with std temp gauges is they dont give you accurate temp...ie 85 deg might be half way, 87 might be 3/4...
Does the motor have clean oil for a while after a change, or does it go black instantaniously???

Wheres a good place to get injectors and pump done? i know its a fairly $$$$ operation isnt it?

where abouts if i get an aftermarket water temp guage do i connect the sender? is it possible to have both guages operating? (another thing my oil pressure guage never goes below half on the freeway, i thought it would drop if the water temp rises, is this true???)

I will check all the filters and install a water temp gauge and see what happens!

I get it serviced every 5k religiously, she doesnt use any oil and it stays clean for a few thousand K's then goes darking ever so slowly.

Pump rebuild about $1200 for a total worst case scenario rebuild, normally closer to $800 for a 2H, so probably $900 for a 12HT.

Injectors are about $80ea rebuilt for a 2H, no idea on the 12HT as the injectors are totally different, but $80 would be a good estimate i would think.

I havent found a suitable place for an extra temp sender so iu just replaced the factory one, you can get adaptor thingos that clamp in to your top radiator hose (cut it in half).

Primary filter is just a wire gause on the inlet to your lift pump, take off the union and it will come out. Tank pickup also has a nylon? gauze over it but you need to drop the tank out to check it, and to get the tank out you need to take your towbar off which is a pain but really not that hard unless all your towbar bolts are rusted.

I recently dropped my tank expecting a heap of crap only to find the tank completely clean.

The water seperator (located on inside of drivers side chassis rail) has been known to cause problems with the fuel system where you lose power briefly etc, can cause erratic fuel starvation and other issues that are difficult to diagnose. You could try bypassing this to see if its your problem.

Injectors on the 2H dont need to be done that often, mine did 420thousand on the origonal untouched injectors, however, with the 12HT and direct injections the injectors are far more important and you should probably have them done regarldess of wether they are the cause of this problem. You should see better economy and maybe more power.

The motor is in good nick internally then .... with the quality of fuel used these days, you can shorten the life of injecters and pumps....toyota recommend 100,000 km injecter cleaning, i know they go 4 times that, but the down side of not worrying is motor wear when they start to spray erratically...especially the direct injection setup, which wears grooves in the piston and then the piston needs replacing or low power is a result.

vSAHARAx wrote:Wheres a good place to get injectors and pump done? i know its a fairly $$$$ operation isnt it?

where abouts if i get an aftermarket water temp guage do i connect the sender? is it possible to have both guages operating? (another thing my oil pressure guage never goes below half on the freeway, i thought it would drop if the water temp rises, is this true???)

I will check all the filters and install a water temp gauge and see what happens!

I get it serviced every 5k religiously, she doesnt use any oil and it stays clean for a few thousand K's then goes darking ever so slowly.

Not sure about your overheating problem but the stalling is quite common for a worn 12HT pump.... apparently it is caused by wear on linkages in the governor which can be reduced by tinkering with the dampener spring or adding a dampener if it doesn't have one already
Cheers
Scott

Hi Troy,
How'd you go with your overheating problem.

I think mine is starting to do the same....
I recently bought the rig, and for the first couple of months the air con wasn't working, and it was a bit cooler... the truck ran rock steady on just above 1/4.
I've now done a bit of work to her.. changed the rad hoses, thermostat, had the rad cleaned and rodded, added some extra silicon oil to the fan hub and had the aircon fixed (just needed a charge) and with the warmer weather I'm starting to get a bit worried...

Runs spot on 1/4 all around town - up to about 80km/hr.
After that, just starts creeping up to around 3/8.
A long drive up an incline can have me sit just below 1/2 - (but no more)

I'm thinking that it shouldn't be moving this much on the open road.. I'm a bit hesitant about hooking up my 2t boat for a long stretch...

I'm hoping I'm not in head gasket / head terrritory.... (or is this normal for the 12ht??)

Cheers

Dave

Just for interest I've got a 12HT with 305000ks on it.

Took it on a trip to Mildura (from SA) to pick up a Motorbike. On a ~30 degree day, towing a motorbike (not that heavy though) and air con on, saw the temp gauge at about 3/8ths cruising a bout 110 +- 5km/h.

When cold, it also tend to drop really low (say 400-500rpm) when putting the clutch in coming to a halt. (like Troy described).

Also on 33" Cooper STT, which is bound to increase the load a little.

Hey There

well its got its power back, but the temperature thing is still in the back of my mind.

up to 105km/h it sits like you said just a tad over the quarter line but 105km/h+ it sits on around 1/2 to just under 3/4 and its really starting to bother me. i bought a water temp gauge and the gauge holder arrived today so will install it on the weekend.

I have just about overhauled the whole cooling system, New Radiator, new hoses, new upper and lower thermostat housing, new thermostat, new water pump. so i dunno if the guage is just sensitive or what will find out after this weekend!

Ok just read something interesting in the "Gregorys's Manual" book thingy.

It says there are two types of thermostats

Opening Temperature-
Low Temperature Type........ 80-84 deg C
High Temperature Type....... 86-90 deg C

What type is supposed to be in the 12HT?????? is it possible i have the high temp type where i should be running the low temp type?

The gauge never went past the bottom line on the gauge because the old thermostat was stuck open, then as soon as i put the new thermostat in the gauge works properly and i start having these higher temps on the highway????

Hi,

I'm pretty sure we're supposed to have th 82 deg C one... that's what the toyota parts guy told me...

I originally put in an aftermarket one (bought from a generic auto shop). Then, thinking I might have bought a dud, went to Toyota...

The two thermostats looked identical. Both of them were stamped with 82 C on them.
I've photos, but no where to post them....



Cheers

Dave[/img]

I had a very similar problem with my old 60. I changed the water pump, thermostat several times and radiator cap a couple of times. In the end it ended up being the temperature sender. I bought a new one, popped it in, and presto, it was all good.

The old sender was getting a little sensitive in the heat range. Mine never boiled over. I pulled it out of the car and popped it in boiling water and read its resistance.....it wasnt what it was supposed to be. I think my old manual had temp readings and sender resistance checks in it!!

Edit- sorry, re read your posts and realise you already changed it.

Well,

Took the cruiser for a run from Mandurah down to Bunbury for christmas- small trailer in tow.

During the day (25/30 degrees) - front and rear aircons on, fridge on, 100 km/hr. sat on 3/8 to almost 1/2 on odd occasions (hills etc).

Came back last night - no aircon, and probably low 20's outside (still hot) but at night time, couldn't get the needle to budge above 1/4. It sat right on the 1/4 mark - just a smidge lower than 'normal' around town driving.

I'm thinking:
* 1/4 mark is the thermostat opening range - and around town I'm controlling at the upper range of the t/stat, and last night at the lower
* That the stock cooling system might be undersized for the Auto VX with the fridge, dual aircon and tranny cooler.

(PS I have another tranny cooler in front of the aircon condenser too)


Any thoughts on the above ?

Cheers

Dave

All i can say is this...when you put your foot down harder, you are putting more fuel in, and making more heat, which the radiator has to disperse.
At 110km/hr you can forget the fan, there is way enough air to go through the radiator....its a balancing equasion...if you are sure your rad is ok, then is it shrouded with other gear that stops flow? or is your motor making too much heat, or is the water not being pumped around efficiently.
I also know that removing the thermistat will allow too much flow through the radiator at revs (110km/hr) and the coolant has less time to shed its heat...
One more thing ive learnt over the years......make sure the earth to the battery is on the head or wherever that heat sensor is...as extra resistance equals more temperature.......
Happy New Year cruisers

Ok the cooling system has nearly been completely over-hauled, the only thing i have modified on the cooling system is the shroud, i dropped it 2" which means a little bit of the radiator is exposed at the top and there is a bit of a gap down the bottom, but i had this problem before i did the body lift so that eliminates that theory. Another thing i failed to mension is that my temp gauge and fuel gauge have spack attacks after driving for around 20 mins, The temp gauge will go all the way past hot and the fuel gauge will go all the way past full then they will come back down. The auto sparkie said something about a voltage regulator thing behind on the back of the cluster could this be a link to my problem? maybe the car doesnt have an overheating problem, maybe my gauge is the problem???

dow50r wrote: One more thing ive learnt over the years......make sure the earth to the battery is on the head or wherever that heat sensor is...as extra resistance equals more temperature.......
Happy New Year cruisers

What is this heat sensor thing you speak of?

Troy

Ok, got the aftermarket guage in, Around town it reads about 103-Deg C and on the freeway 110 Deg-C. What are peoples thoughts, is this too hot?

Troy

vSAHARAx wrote:Ok, got the aftermarket guage in, Around town it reads about 103-Deg C and on the freeway 110 Deg-C. What are peoples thoughts, is this too hot?

Troy

way too hot

should sit on 85/87degrees c and only rise when you really nail it up hill.

Over 100c is too much, with a 13psi radiator cap you can go to about a max of 115c before she will boil out.

the factory gauge sits on a 1/4 then around town then starts to move up at around 107 - Deg C

vSAHARAx wrote:the factory gauge sits on a 1/4 then around town then starts to move up at around 107 - Deg C

My 2H sits on 85degrees C all day around town.

Same on freeway if i sit on 90/95 (or less).

100km/h she gets a bit warmer but nothing serious, 95 tops,
110km/h she will get to 100C up hills if im really pushing.

If it goes over 100C and it has pulling a trailer at speed I always back off and let it cool down.

what do you suggest i do? i have to fix it b4 saturday going up to Fraser Island

id check simple things first

Verify your (new?) aftermarket guage isnt faulty, unlikely but possible.

If you really need it by saturday id be taking it to a radiator shop and getting them to fix it or at least identify your problem, they should be able to isolate a problem much easier than you will be able to.

I think you need to confirm if the engine IS getting hot ot not. Obviously a problem with your gauges / gauge regulator if the fuel gauge goes crazy too. EDIT: just re-read bit about aftermarket gauge, 110 is too hot! Should be ~90 tops.

Your fan shroud needs to be rectified to close the gap at the bottom, as the fan needs to only suck air through the radiator core.

If you consider it down on performance and you are having heating issues, and the engine is in good nick then you may have a problem with the timing advance mechanism on the fuel injection pump.

Hmm,

The number of replies here that are implying (Stating ?) that their trucks get hotter when running on the open road has me wondering if the cooling system isn't a bit on the small side.

Yes the rad looks fairly large, but with the auto trans and dual aircon (and fridge), Im wondering if it aint just a bit underdesigned.

My understanding is that the thermostat should 'control' the temp and keep it nice and stable around the opening temp. With a larger rad, the temp wouldn't rise on highway runs, and the truck temp would stay more stable (cooler).

Anyone know if a larger ( Custom ?) rad has been tried ?


Cheers

Dave