Outer Limits 4x4 Board

I recently upgraded to a RZN169 SR5 I am having cooling problems,
When?
long up hill low range 4wd'ing
high speed highway 110kph + all good up to 110
low speed hill climbs - Mt tamborine / Montville etc.
What I have done
changed clutch fan hub NEW
Flushed radiator new coolant
removed radiator and air con condenser cleaned finns etc. (wasn't too bad)
I also had an issue with Knock sensor which was overfulling and retarding the ignition timing (this has also been rectified) but I still have the overheating problem.

Turning on heater and internal fan seems to work but I prefer the air con in the summer.

car has 270,000 ks would this be a problem?

probably need to replace your radiator or recore it or have it striped apart and rodded to ensure all of your cores are allowing fluid to flow freely and as such cooling efficiently.

to me its not a fan issue as its low and high speed.

iys when engine under load, so either fuel running lean? but most likely just a crap radiator.

Or pull the thermostat out, throw it in a bowl of boiling water, check its opening fully.

Although Low range overheating is odd, granted air flow is minimal but general load on the motor is alot less also.

You have the fan shroud on the radiator dont you???

K's are fine, depending how its been treated and maintained, i doubt it has anything to do with the k's.

thehanko wrote:probably need to replace your radiator or recore it or have it striped apart and rodded to ensure all of your cores are allowing fluid to flow freely and as such cooling efficiently.

to me its not a fan issue as its low and high speed.

iys when engine under load, so either fuel running lean? but most likely just a crap radiator.

ok I will try the proper radiator clean and thermostat.
and yes berad the radiator cowl is there and in tact.

you dnt realy need the radiator shroud as i'v run mine for ages and didnt even get hotter of colder, just stayed at the normal runing temp. but decided to put it bak on as a rock smashed one of my cores

but i would be checking the thermostat, you've done all the rite steps. if you the check the stat and it works, i'd be getin the radaitor cores replaced

also what about the water pump????

Just take it to a shop, it costs next to nothing, they can tell you if its clogged or if your wasting your time.

The 3rz is a tough motor id be suprised if the motor its self is causing the problem.

berad wrote:The 3rz is a tough motor id be suprised if the motor its self is causing the problem.

just prefect for a sig line. i love me 3RZ, i keep her happy servicing etc and she keeps me happy when i plant it with 32's and 2 inch lift beating stock cruises and lux's of the lights

thehanko wrote:probably need to replace your radiator or recore it or have it striped apart and rodded to ensure all of your cores are allowing fluid to flow freely and as such cooling efficiently.

to me its not a fan issue as its low and high speed.

iys when engine under load, so either fuel running lean? but most likely just a crap radiator.

I took the old radiator out and there were coolant stains on the core in a couple of spots, So I replaced the radiator with one I had come in during the week with 2008 stamped on it, now its not getting hot on the highway anymore. Thanks for your help guys.
Off to Cruiser park Tuesday to try low range.

can anyone give me idea on mine?
got a 3rz in 89 dual cab, was running 22r radiator with 16in davis craig thermo. with this setup it was overheating at speed above 90km/h and only on warm days. I then changed to a 3vz radiator which was heaps bigger, this made it slightly better, only overheating at speed under load, up long hills ect, but the problem is still there. I then checked the plugs and i reckon it might be running a bit lean, im going to get this checked after the Christmas break. I have changed all hoses and thermostat.

Besides running lean the other idea i have is airflow to the radiator, even at 100+km/h the thermo is still coming on. i have two xgt's on the front bar.

Any other ideas?

Get rid of the thermo fan and run an engine fan.

RUFF wrote:Get rid of the thermo fan and run an engine fan.

i wish i could but it wont fit without alot of work, i understand they are more efficient e.c.t but i really doubt the thermo is my problem.

If the fan was the problem i would expect the overheating to occur at low speed high engine rpm and load which it doesn't

berad wrote:Or pull the thermostat out, throw it in a bowl of boiling water, check its opening fully.

Although Low range overheating is odd, granted air flow is minimal but general load on the motor is alot less also.

You have the fan shroud on the radiator dont you???

K's are fine, depending how its been treated and maintained, i doubt it has anything to do with the k's.

Just throw it out and get a high flow colder one