12HT Sluggish & Gets Warm On Freeway Plz Help!!!

[Shadow]

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

These trucks werent designed to do 120, they will drive all day every day at 90 pulling heavy loads (2tonne), take them to 110 (about 2750rpm i think) and they heat up a bit.

If you want something to do 120(110 fully loaded), get a newer cruiser, they will happily do it.

[vSAHARAx]

GREAT NEWS!!!!!!!!

BL**DY fANTASTIC NEWS!!!!!

SHES ALL FIXED, factory gauge has a minor earth problem, and the aftermarket guage i put in the sender was rooted. i booked it in to Red Devil Radiators in Moss St and they:

Removed Thermostat and Tested - All Sweet
Pressure Test System - Thumbs Up
Reverse Flushed Radiator - All Good
Reverse Flushed Block - fair bit of stuff come out, now ok

They let her idle for a bit and the factory gauge was just under 1/4 and the after market guage read about 102 Deg C. So he pointed his laser temp pyro gauge thing at the block and it read 72 Deg C

This arvo i went and bought a VDO electric water temp gauge and threw the other POS away and shes running sweet!!!!

I took it for a burn with spotties (LightForce XGT's) off and then with the spotties back on and made no difference temp wise, Around town Aircon on 82-83 Deg C (factory gauge just above 1/4), on the freeway Aircon on pushing it really hard from 100km/h to 125km/h and held it there for a while and it only shifted up to around 85 Deg C (mean while factory gauge is just above half)

Thanks Heaps Everybody for your input, has been very greatly appreciated!

Cheers Troy

[Shadow]

much better.

Toyota manual says your operating temp is 82degrees C.

[vSAHARAx]

ill be a little more relaxed towing the trailer up to fraser island on saturday, perfect timing

[its aford not a nissan]

I took it for a burn with spotties (LightForce XGT's) off and then with the spotties back on and made no difference temp wise, Around town Aircon on 82-83 Deg C (factory gauge just above 1/4), on the freeway Aircon on pushing it really hard from 100km/h to 125km/h and held it there for a while and it only shifted up to around 85 Deg C (mean while factory gauge is just above half)


sounds like you didnt really have an over heating issue after all

[wgw76gd]

Here's another interesting bit of info....

Just put new rad / water pump in the old girl (61 12h-t). Got the block back flushed by a radiator mob and filled with new coolant.

Took it away, and couldn't get the temp gauge to budge !! Only moved ever so slightly at 100 on the freeway.
Hooked the boat up and took it for a run - got it to get to 'operating' temp - (1'st mark up the gauge) - but no further, even giving it a fair amount of stick.

Diagnosis ? - had to be the thermostat - i figured. Took it back to them, and sure enough, the thermostat disc guide pin had come out from his little hole (They said they do that sometimes ?) and the disc was cocked over to one side - letting more water through.

New thermostat, and the gauge jumps very quickly up to the first line, and stays there - around town and cruising on highway.
Cruising on the highway with aircon on = temp gauge smidge higher (small but noticeablt to a trained eye who has been messing with this for a while !!!)
Now towing the boat the gauge comes off the bottom line and heads towards the middle (second line) - but not dangerous or anything.

I'm thinking
1) Yah!! no head gasket probs for me !!!!
2) Thermostat doesn't open enough to maintain constant water temp
3) Getting an aftermarket hi flow thermostat would hold the temp steady whilst towing (Does anyone know if there is one ?)
4) Where I have it is better, since it should run better a little hotter, and I will see much earlier if I have any problems.

Cheers

Dave

[vSAHARAx]

Here's another interesting bit of info....

Just put new rad / water pump in the old girl (61 12h-t). Got the block back flushed by a radiator mob and filled with new coolant.

Took it away, and couldn't get the temp gauge to budge !! Only moved ever so slightly at 100 on the freeway.
Hooked the boat up and took it for a run - got it to get to 'operating' temp - (1'st mark up the gauge) - but no further, even giving it a fair amount of stick.

Diagnosis ? - had to be the thermostat - i figured. Took it back to them, and sure enough, the thermostat disc guide pin had come out from his little hole (They said they do that sometimes ?) and the disc was cocked over to one side - letting more water through.

New thermostat, and the gauge jumps very quickly up to the first line, and stays there - around town and cruising on highway.
Cruising on the highway with aircon on = temp gauge smidge higher (small but noticeablt to a trained eye who has been messing with this for a while !!!)
Now towing the boat the gauge comes off the bottom line and heads towards the middle (second line) - but not dangerous or anything.

I'm thinking
1) Yah!! no head gasket probs for me !!!!
2) Thermostat doesn't open enough to maintain constant water temp
3) Getting an aftermarket hi flow thermostat would hold the temp steady whilst towing (Does anyone know if there is one ?)
4) Where I have it is better, since it should run better a little hotter, and I will see much earlier if I have any problems.

Cheers

Dave

Everything you said there is exactly what i experienced, which is why i started this thread
Mate dont stress about it, if you want peace of mind install a good quality aftermarket water temp gauge (i installed a VDO). Drove up to fraser island in january, Towing around 1200kg of trailer, with F&R Air-con on and the fridge, the highest it went while cruisin was 85 degC sitting on around 110-115km/h. While the factory gauge was just above half. At one stage i had the old girl wound up to 130 just before the overtaking lane started so i could get a couple of cars as the overtaking lane was up hill . She dropped back to around 125 at the top and factory gauge climbed to the line above half (so around 3/4) and it went to 90 Deg, thats the hottest it got. when i get motivated i might change the factory temp sender apparently they can get a bit sensitive.

[sixdeetoo]

Hey Troy,

Good thing about this thread is that when on the sand on stocko and my truck workin it - the F@ctory gauge went to a bit above the halfway; but because you had detailed the travels of your truck and I knew:

1) My thermo was good.
2) My radiator and coolant was fine
3) The rest of the donk was sweet

I was able to keep on rocketing along - and naturally when the working slowed - the gauge came back to normal.

Ah- knowledge without the negative experience - Thats Gold!

Bran

[chunks]

Very interesting read fellas! My 2H turbo does a similiar thing, round town it sits between 1/4 and 1/2 but out on the highway it sits on 1/2 and when you start going quicker than 100 kays or up a hill she creeps up to 3/4. I had been told by one bloke that all cruisers run warm on the highway but after reading this it sounds like he was talking out his rectum.

I'm about to buy VDO boost and pyro gauges so i'm thinking ill grab a water temp while i'm at it. My radiator was replaced (by the previous owner, i've only had the truck about 6 weeks) a year or two ago but when i got it the coolant was pretty dirty so i flushed the radiator and motor/heater core etc out and filled it with quality coolant. I've never checked the thermostat or replaced the waterpump. Also she does blow a bit of black smoke i was going have the injectors and pump checked out so i was thinking maybe the EGT's are getting a bit high under load hence me wanting to get the pyro installed asap.

I will be driving out to Alice Springs in july so i don't want any cooling system issues. I think first step is to get the gauges in so i can get a clear idea of whats happening.

Cheers,
Bill.

[sixdeetoo]

Bill,

Just check that your replacement radiator is an Aussie / Toyota original capacity. A few years back the radiator in my truck was replaced with a cheaper option (Thai import) which functioned but crapped itself after corrugations on the lower seam.

After closer inspection the core was F@#$. and had commenced resembling a cadbury flake - wifes' words. Thank heavens she noticed the green dribbles - and it wasn't on St Pats day either.

Cheers.
Bran

[vSAHARAx]

Hey Troy,

Good thing about this thread is that when on the sand on stocko and my truck workin it - the F@ctory gauge went to a bit above the halfway


Bran

Thats exactly what my truck did on fraser yet she never went higher then 85Deg on the VDO guage

I was told not to trust an aftermarket guage but i took it to the radiator mob and they got one of those heat gun things where they point to an object and it tells you the temp, and the VDO is pretty well spot on

[chunks]

Priced a VDO Pyrometer yesterday, $340 trade...fark me dead can you get them cheaper anywhere else!!??!!

[tuffsahara]

yeah my guage only moves when its workin hard and trop mine pumps out 9 psi aswell so id say thats pretty normal goood to hear shes all good again

[wgw76gd]

$280 for my pyro (VDO) from local Auto west shop

(Goes much nicer with 9 psi !!!!!)

Dave

[bucko]

I am looking at getting some gauges including boost/pyro/temp to monitor the vitals. Do vdo have head temp sensors or is measuring the water temp the only setup?

[davec]

good on ya sahara cause mine is doing the exact same thing,god around town but out on highway when im bumping her along a bit it will go up to about 2/3rds sometimes,ive got the temp and fuel gauge spiking sometimes also,i'll go good aftermarket gauges,but im also thinking about one of those auzzie desert radiators,hopefully next year we'll be running around the pilbara etc for the whole year so i wanted to get this heating prob sorted out,my rad looks perfect,might get gauges etc sorted out then new water pump,radiator might be fine by the sounds of it.
cheers dave

[vSAHARAx]

ive got the temp and fuel gauge spiking sometimes
cheers dave

Mine does that too, what exaclty causes it, im constantly sh!ttin myself when i look at the temp guage and its all the way in the red, then i look at fuel gauge and calm down a bit. the auto sparky doesnt know what it is either?!?

[davec]

oh i know what it is but havent tackled it yet,apparently there is a regulator on the back of the temp gauge,it controls temp and fuel gauge etc,well apparently you can pull it apart quite easy and there is meant to be a earth connection or something in there that gets corroded over time and causes the problems where having,clean or lightly sand connection or replace,been told the regulator isnt that dear,but most just clean it up,petrols suffer from it too.
cheers dave

[vSAHARAx]

next time someone has their cluster pulled apart and knows where this regulator thing is can they take a picture please

[TURBO60]

my 60s temp and fuel some times hits the top and then gos back to normal i just left it

[davec]

yeah but what worries me turbo is im not running aftermarket gauges at the moment and if there doing this r they reading right,no good running around with a dodgey water temp reading,its just a worry when you start towing etc or if ya running around the top end or the pibara where things are a bit warmer,you start towing loads in that country and you allways find yourself checkin that temp gauge.

if it runs hot up their,only one thing to do,pull over crack a tinny and let her cool down.