Autobox separate cooler help please

[Markspark]

Hi all i have a 2002 Colorado 3.0 D4d with the auto box. I'm looking to fit a standalone oil cooler for the gearbox as i seem to be using a little water, i have checked the dip stick for the auto box and all seems fine. So at this stage i have ordered 20ltr of atf fluid to do a full flush of the box but what i do need to know is what size of oil cooler will be best suited to the car i have seen 6 row, 8 row and 10 row but im unsure which to buy. I have read through pages and pages on here but cannot seem to find a definitive answer. I do understand that the cooler in the coolant rad is also a warmer but im willing to take my chance on not needing this part of the system

Any help is appreciated

 

[Chris]

Mark, I cannot give you a definitive answer on this and I am not sure that there's going to be a wealth of information that shows the effect of a range of different coolers. It certainly would be a complicated calculation on paper. Remember the OEM cooler is in the radiator, yes and it's not that big but it is water cooled. An external cooler is going to be air cooled so will need to be positioned where it will get the most benefit. This may be a deciding factor at the end of the day - what space do you have in which to put the unit. As for the cooler also being a 'warmer' I think that's more useful in very cold weather where the water being returned to the engine block after being through the rad is tepid. if the rad is heating the oil cooler significantly then it's not much of a rad is it! It might just mean that in cold weather it takes a little longer to warm up. From memory the autobox has a device that limits gear change until a certain temp has been reached to avoid problems.

 

[silvercruiser]

If it was me, i would keep it standard, put the money towards a new radiator and you know it will be good for many more years, you also have peace of mind that the engine is getting cooled with a free flowing new radiator. They are so easy to change too.

 

[flint]

I'd be inclined to go with Silvercruisers thoughts, unless you are heading to the desert and/or do a lot of heavy towing. Roughtrax have pattern ones: https://www.roughtrax4x4.com/toyota...ators/ava-engine-cooling-radiator-to2249.html

If you do decide to go down the separate cooler route, there are kits sold in Oz, one of which (
https://www.kaon.com.au/store/p44/Prado_120_Transmission_Cooler_Kit_-_1KD_and_1KZ.html ) uses this cooler which is rated at just under 14,000 BTU:
https://daviescraig.com.au/product/transmission-oil-cooler-21-plate-hydra-678

 

[Markspark]

My car is mainly used for towing our caravan that said i have never seen the gearbox high temp light come on whilst towing. Im not 100% sure the water is going into the gear box im doing this to rule out the problem.

 

[Shayne]

I'm with Silver that engine ain't known to overheat so just overhaul what you got .

 

[Markspark]

The 2nd question is what antifreeze is best as roughtrax only sell pre diluted also how do i find the capacity of the coolant system

 

[Shayne]

I use Toyota red from Roughtrax just because i don't want to think about it

https://www.roughtrax4x4.com/blog/land-cruiser-kzj90-kzj95-1996-2002-vehicle-specifications/

Says 9.5 or 11 litres depending on whether or not you have rear heaters .

Change the thermostat to , theres a towing stat that opens earlier for the 1KZ , so likely one for the 1KD if its not as i suspect the same part .

 

[Markspark]

Cheers guys im going to scrap the 2nd cooler idea and just go for a new rad but will still fulsh the gear oil as planned

 

[Markspark]

Im thinking with view to towing the caravan i normally tow through the night and its cooler then so i should be ok