Radiator Recommendation

[me3@neuralfibre.com]

Can anyone recommend a radiator Guru?

I've been tryign to track down (unsuccessfully) an overheating problem in the 1HZ.

Next step is replace the radiator, but I can't cough $1200 for an OEM Toyota one.

There is a belief that it is better than the aftermarket jobs.

I hear of people with the PWR's that still overheat, so not sure if I trust them either.

Any tips appreciated.

Thanx
Paul

[dumbdunce]

is the radiator the last straw? I'm not familiar with your overheating saga so before I comment, is there a thread where it is explained in a bit of detail what you have done so far?

tried wreckers for a second hand genuine radiator?

in my experience, if you have stuck with toyota red coolant (or even a decent aftermarket coolant) for the life of the vehicle, the radiator is highly unlikely to be the (only) problem. The cooling system on 80/105 series has huge excess capacity, it takes a lot to get them to consistently overheat.

[Yom]

have you tried pop riveting some alloy sheet and paddle pop sticks togther?

and what is actually wrong with the current radiator? had the end tanks removed and cleaned?

[+dj_hansen+]

From Lcool:

Now for those that don't recall previous similar discourse with me lamenting my overheatin woes.

• I have a '98 HZJ105 GXL w/ an AXT turbo kit on it set to 10PSI. Car is an Auto.
  Car has 260,000km on it.
  It over heats when pre-turbo EGT is sustained over 550C. It climbs slowly at 570c, steadily at 620C, and fast at 660C. EGT's top out at 670C unless revved over 3500RPM, when they spike to 720c or more.
  
  Radiator was professionally stripped, cleaned and an in tank auto cooler fitted at 220,000km simply cause I am paranoid. Radiator was found to be clean.
  
  Replacement fan clutch (aftermarket Daikin) fitted when I noticed overheating issues (loaded - hills). That didnt' work. OEM clutch exorbitantly paid for and fitted by myself - no difference there either.
  
  It uses no coolant (cept last month when it popped the heater core - liekly due to overtemp / pressure - I think I was at the top of the Blackbutt range with the radiator cap venting when the core popped.)
  
  It does NOT overheat offroad at any speed, EGT's alwasy below 350c offroad (no comment on sand - haven't tried). It DOES overheat at 130km/hr even on a cool day with EGT at 620C. ie - I don't beleive it's an airflow issue.
  
  The fan clutch behaviour is a little strange. I reckon it doesn't lock and unlock until near the red by ear. Yes it's spinning and pulling air, but it doesn't really roar util it's near the red. It's the third one to be the same.
  
  Yes the gauge is approx accurate - just on the red is when the radiator cap opens - 16psi I think. Not sure on exact water temp - depends on both pressure and coolant mix. 125c ish I would think.

Now where to start - thoughts?

• a) Cylinder Leakdown test?
  b) New OEM radiator? (or strip and sikaflex this one - alloy tabs will break if stripped)
  c) Overfill the fan clutch (instead of the brand new OEM one)
  d) Different Turbo (My EGT's are too high on cruise I reckon often 500c+ on the flat). Possibly wrong trim.
  e) Take head off and inspect?
  f) Water Pump Pressure Test
  g) Intercool (get intake temps down - but will not help radiator) (I have a HUGE one in shed that will fit)

Thoughts please?
Paul

Is there a direct link do you think between EGT and Coolant temp? obviously the radiator appears the likely culprit, is there someone of testing the efficiency of a radiator at a shop before shelling out the $$ for a new one that is potentially the same?[/u]

[dumbdunce]

there is a link between EGT's and coolant temperature but it's not a "direct" link. you can have EGT's of say 550C at 1500rpm and the same EGT at 3000rpm, but at 3000rpm there is twice the heat energy in the exhaust; the gas itself is at the same temperature but there is twice the gas flow - the metal parts (manifold, turbine housing, head, pistons etc) will be hotter so there is more heat in the coolant and oil. ambient conditions, airflow/roadspeed etc all obviously combine to modify the equation.

is there anything in front of the radiator; lights, bullbar/winch, bug screen, shooroos, etc?

does the vehicle have a body lift or ricer bonnet scoop?

are there under-vehicle accessories (water/air/aftermarket fuel tanks, bash plates, even nerfs/sliders) that may interrupt airflow beneath the vehicle?

is the auto trans good; has it been regularly serviced? have you put a temp gauge on the transmission cooler lines to see what temps the atf is getting to before it hits the radiator? can you connect it to an external cooler and eliminate it from the equation?

what oil do you use - is it of a higher viscosity than OEM recommendation?

you don't mention the thermostat; have you tested it and/or changed it out? it's a pain on a 1HZ especially with a turbo but it's a cheap part and only an hour to change it. don't remove it; uncovering the bypass port is bad, mmkay.

how about the water pump?

it's pretty easy to stick a thermocouple into both ends of the radiator (under the hose ends) and monitor the temperature difference across the radiator with a couple of multimeters, but measuring the coolant flow is a lot trickier.

I agree your EGT's are high, but not high enough to be the only cause of your problems. what's downstream of the turbine housing? any restrictions/dents/clogged muflers etc will keep the manifold EGT's high and dramatically reduce turbine efficiency.

my 1HZ 80 series with denco turbo could be held flat stick at 150ish km/h at 10psi without a flicker on the temperature gauge; EGT's just over 600C POST turbo.

as a quick and dirty test to see if the problem is airflow related (and the fan not clutching up until almost in the red sounds like airflow to me; the clutch relies on signal air through the radiator to get it to lock up), get one of your old fan clutches, open it up and lock it (throw in a handful of sand or something), install it with the fan locked solid to the water pump, go for a drive and see how it performs. it's also helpful to install a calibrated temperature gauge, as the response of the factory gauge is not linear; there is a considerable temperature range where the needle will sit right in the middle of the gauge, once this range is exceeded the needle will shoot up towards the red; a gauge with numbers on it will have a more linear response.

anyway there are a lot of cheap and effective things to try before throwing money at the radiator, and given that it was cleaned with the tanks off not that long ago, it's likely to still be good.

good luck, these sorts of problems can be very trial and error/ hit and miss to diagnose.

sort out the overheating problem THEN fit the big intercooler; sticking a great airflow restriction in front of the radiator will not help the cooling system if its performance is already marginal.

cheers

DD

[awill4x4]

I guess it depends on where you are measuring your EGT's, post turbo you should be looking at a maximum of 500-550C under load.
If you are getting EGT's of 600-700C and your measuring them post turbo you are over fueling the engine.
High EGT's mean high combustion temps which will overheat the coolant that is circulating around the combustion chamber.
Get your car checked by a diesel specialist (preferably on a dyno) to see if it's over fueling, lots of 1hz's have died prematurely because of incorrectly set fuel pumps when fitting an aftermarket turbo kit.
Regards Andrew.

[GRPABT1]

Can anyone recommend a radiator?

An alloy one

[me3@neuralfibre.com]

there is a link between EGT's and coolant temperature but it's not a "direct" link. you can have EGT's of say 550C at 1500rpm and the same EGT at 3000rpm, but at 3000rpm there is twice the heat energy in the exhaust; the gas itself is at the same temperature but there is twice the gas flow - the metal parts (manifold, turbine housing, head, pistons etc) will be hotter so there is more heat in the coolant and oil. ambient conditions, airflow/roadspeed etc all obviously combine to modify the equation.

550+C pre turbo = overheat @1800 - 3500RPM (auto, hard to test below 1800)
580 = slow temp climb
680 = fast temp climb
But Climb it does.

is there anything in front of the radiator; lights, bullbar/winch, bug screen, shooroos, etc?

Factory alloy bar, aftermarket winch mounted very low and direclty in front of a same sized bar that is part of the body, Hella 4000's
Overheats at 10km/hr (toowoomba range with 3T of trailer), or 140km/hr - (out west, high speed, empty)

does the vehicle have a body lift or ricer bonnet scoop?

No, suspension 2" only

are there under-vehicle accessories (water/air/aftermarket fuel tanks, bash plates, even nerfs/sliders) that may interrupt airflow beneath the vehicle?

No - all factory atm.

is the auto trans good; has it been regularly serviced? have you put a temp gauge on the transmission cooler lines to see what temps the atf is getting to before it hits the radiator? can you connect it to an external cooler and eliminate it from the equation?

Yes serviced. It matches or stays cooler than coolant. Yes have temp probed it. It has a very large factory cooler, + the in radiator bottom tank cooler.

what oil do you use - is it of a higher viscosity than OEM recommendation?

Toyota Genuine or Penrite

you don't mention the thermostat; have you tested it and/or changed it out? it's a pain on a 1HZ especially with a turbo but it's a cheap part and only an hour to change it. don't remove it; uncovering the bypass port is bad, mmkay.

Replaced and tested the old one too for good luck. Also done cap.

how about the water pump?

Played with that last weekend for laughs. 2200RPM = over 1.5m of pressure - PLENTY of flow when tested from the in / out of heater flow points. Was LOTS of airation, due to mix of air drawn in and possibly cavitation. I dont' think it was cavitation personally - mastly indrawn air from testing.
http://autospeed.com/cms/A_110478/artic ... larArticle

it's pretty easy to stick a thermocouple into both ends of the radiator (under the hose ends) and monitor the temperature difference across the radiator with a couple of multimeters, but measuring the coolant flow is a lot trickier.

I'm very suspicious of the radiator for a few reasons.

I agree your EGT's are high, but not high enough to be the only cause of your problems. what's downstream of the turbine housing? any restrictions/dents/clogged muflers etc will keep the manifold EGT's high and dramatically reduce turbine efficiency.

Considered this. 2.5" mandrel system w/ straight through can. Possibly blocked, but no audible pressure (hissing etc). Pressure gauge and a drilled port required to test - or angle grind the exhaust apart to check. System is not new - probably fitted with turbo @7500km. Vehicle is not 250,000km.

my 1HZ 80 series with denco turbo could be held flat stick at 150ish km/h at 10psi without a flicker on the temperature gauge; EGT's just over 600C POST turbo.

I wish. Boil me baby. Speed and boost are about same as mine. EGT seems close. Was your's intercooled?

as a quick and dirty test to see if the problem is airflow related (and the fan not clutching up until almost in the red sounds like airflow to me; the clutch relies on signal air through the radiator to get it to lock up), get one of your old fan clutches, open it up and lock it (throw in a handful of sand or something), install it with the fan locked solid to the water pump, go for a drive and see how it performs. it's also helpful to install a calibrated temperature gauge, as the response of the factory gauge is not linear; there is a considerable temperature range where the needle will sit right in the middle of the gauge, once this range is exceeded the needle will shoot up towards the red; a gauge with numbers on it will have a more linear response.

Tried my fluke w/ temp probe last weekend - interesting results.
Can't replicate overheating whilst still, and can't test much when under huge loads whilst driving. (I would give anything for some thermocouple extensions)
Water temp maxed at 88c. (Fluke temp probe in coolant top tank cap off)
fan cycled in at 85c and out at similar
Air into radiator - 45 - 55c (from AC & auto trans cooler)
Air out - fan uncoupled - 65c
Air out - fan coupled - 85c

I am wondering if the core is blocked near the centre, hence the strange fan coupling behavior I have noticed.

My concern with a locked fan (done this with ute and mates patrol) is that a 100% fan may just cover up the faulty radiator.

anyway there are a lot of cheap and effective things to try before throwing money at the radiator, and given that it was cleaned with the tanks off not that long ago, it's likely to still be good.

good luck, these sorts of problems can be very trial and error/ hit and miss to diagnose.

sort out the overheating problem THEN fit the big intercooler; sticking a great airflow restriction in front of the radiator will not help the cooling system if its performance is already marginal.

cheers
DD

Hmm - kindof agree but

Down to

a) Cracked head - next test - that gas HAS to go somewhere. Overflow hose going into 5l bottle 1/2 full in passenger floor. When I test next (may be some weeks). Boiling steam will condense and not "bubble" to surface. Leakign combustion gas will bubble obviosuly. This is I think better than leakdown test as it will be done under operating conditions.

b) Radiator - try another. Strip this one, see how many fingers break off the alloy / plastic joint, sikaflex it back together (yeah - flame on)

c) Faulty block / engine (no idea - flow pattern?)

d) Fueling - timing, quantity, pattern.

e) Mismatched turbo - resultign in high EGT's. 550C at 110km/hr w/ roofracks is a bit high compared to some other cars I know. the 33" tyres didn't help. Too small an exhaust turbine could restrict the flow. It's a '99ish AXT system sitted by Motsons.

The safari setup I saw last week didn't overheat. That's my baseline that gives me confidence this can be fixed despite the naysayers that state "1HZ + turbo will overheat". He has 33", full safari setup, auto, same auto coolers, more gear (chopped to ute w/ box), trailer, dual tanks etc etc. He pushes his.

In a side by site with a mates Manual 80 w/ 1HZ and 10PSI and 33's - they were head to head from 40 to 110km/hr EXACTLY, despite the 80 being lighter.

Thanks for your time DD. Feel free to post or PM any more thoughts. Appreciated. Have chased this for 12+ mths now.

My plan of attack is
a) Try to strip this radiator. If it's breaks, replace it. If I can get it open - re-use it. Adjust and overfill a spare clutch I have. Pull off water pump for inspection. Pull and test and probably replace thermostat. Refill w/ OEM red coolant for possible cavitiation reasons mostly. Check valve timing.
Test drive and check for head crack bubbles as above.

b) Get the injector pump and injectors overhauled. Check tappet clearances.

c) Burn it, claim insurance.

Paul

[bogged]

FWIW, I had my GQ radiator tanks removed, and fully cleaned and got the works.

Still overheated.. took it elsewhere, they said nothing had been done the first time, just a new paint job and rivets... still 30% blocked at second place only a few mths later.

so take it elsewhere and get it re-done.

[tj81]

any chance the temp guage is dodgy.

[the gun]

I guess it depends on where you are measuring your EGT's, post turbo you should be looking at a maximum of 500-550C under load.
If you are getting EGT's of 600-700C and your measuring them post turbo you are over fueling the engine.
High EGT's mean high combustion temps which will overheat the coolant that is circulating around the combustion chamber.
Get your car checked by a diesel specialist (preferably on a dyno) to see if it's over fueling, lots of 1hz's have died prematurely because of incorrectly set fuel pumps when fitting an aftermarket turbo kit.
Regards Andrew.

x2
my local diesel guru sets maxiumn fuel to achieve 550 c on load. Any higher temps and ur risking things melting, like pistons.