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Air In Coolant System / Bleed Procedure



Good morning!

I have a 2017 HD10 (no heat) and I went to flush the coolant yesterday evening and refill the system.  When I refilled right near the max line on the reservoir, it burped out of the overflow for about 30 seconds before I shut it off (it was not an insignificant amount - maybe half a quart? The bleeding procedure really doesn't say much - but to fill the reservoir, run the machine (with the coolant cap on) until the fan kicks for a 2nd time, shut if off, then refill as needed. It started to bubble over 15 seconds or so after the fan kicked on for the first time.

Is this normal behavior? I'm going to try again here in a bit but figured I'd let you smart people help me sort it out in the event there's a larger issue at play. I'm inclined to believe there's air in the system somewhere but the manual seems to indicate that this seemingly rudimentary procedure will sort that out for me? I've attached the procedure from the maintenance manual in case I'm reading it wrong!


HD10 Coolant Replacement & Bleeding Procedures.pdf

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Gday ST

     I have the same issues with my HD8 2017.Seems like there is air the the system it has purged out of the coolant tank twice. Approx 3 litres once and half a litre the other. I have found leaks under the throttle body (think its the throttle body ) but to tighten them all up you need to remove the body. I have heard of a guy having a spilt internally of the radiator ( 2 years old ) Had the radiator replaced and a system flash and he said it was fixed.

Seems to be a common issue. I am now looking to purchasing a BUDS 2 unit because without it you cant really service the vehicle properly, cant even reset the maintenance message after an oil change without it. The mode and lights procedure never works.

Seems to like having the coolant at half way or under, when you put it or MAX (engine cold) it will just purge out.

Anyone else having this issue ? Thoughts ?

Im now looking at a new Rad and O rings below throttle body and maybe a gasket maker there as well. I think that where air is being introduced and the RAD then gets bad internals.

Also have put a new steering rack in after 4 years, completely under rated piece for this type of vehicle with its power and wheels/tread 

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Update on this post for anyone who is interested. I fixed the problem

Replaced radiator with an aftermarket one $350 AUD including postage ( suspect the original one was damaged as had coolant stains, not alot but some )

Bought a BUDS 2 unit with a 1 year dealer  $1000 AUD

went thru the intake area of the engine, top of cylinders

replaced all the leaking coolant o rings  ( the original rubber around metal washer ones ) 

used normal o rings and tightened them ( originally they were too loose IMO and causing the leak and air in the system )

bleed the coolant system, i found having the system just get to temp and fan cycle twice did jack all to get the coolant thru the system

take it for a blat then check the level once cool, did this twice to get.

plugged in the BUDS and flashed the system

I only had one fault/error before this work, the 02 sensor and a over temp message ( alot of them )

After the flash there were no errors, I will replace the 02 sensor soon tho

Its been 2 months now and its been driving well, no overheating issues


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