Sunday, Apr 26, 2015 at 12:06
G'day 19738662,
You've got the main thing covered which is any fall back with warranty.
The bleeding of the system does have merit. Usual indicators are an audible gurgling sound from your heater and the most obvious physical sign is a lack of performance from your heater. As a rule of thumb, most air locks happen in the heater core and normally after a coolant change not after many kms in service unless there has been some coolant loss and the coolant over flow pipe in the bottle has been allowed to draw air in.
This can happen if the system was flushed and refilled, it burped the air out but hasn't been checked since allowing the level in the recovery bottle to drop below the level of the pipe outlet. Or.... if the recover bottle itself has a leak. Rub through? A rouge screw from the fitment of something else? A stray
rock?
A pressure
test can
check for a few things....the system holds pressure (seen on the gauge reading), fpr any external leaking of coolant and also, especially in the case of a diesel, any internal leaking. Any coolant escaping into the combustion chamber will show up as a hesitation when cranking the engine over immediately after the pressure
test. That is the "worst case scenario"... a stationary engine with coolant in it. Not so noticeable while the engine is running.
An external leak while driving will generally give off a distinct odour and a leak internal to the combustion chamber will show up as signs of steam from the exhaust..... although unlikely. Remember the pressure in the combustion chamber is a squillion times higher in a diesel than the pressure in a cooling system so the migration would be of pressure into the radiator, not the other way around.
It's always hard to diagnose any problem from a keyboard so the best you could go with is recommendations. Hence I'm not going to say what it is, rather what it's likely to not be, and my recommendations.
Summary..... radiator cap is fine. Going by your info, I'm doubting it to be a head gasket/serious engine problem. A sticking thermostat will not lead to an unrecoverable coolant loss. The notion of spotlights etc leading to a warmer operating temperature has merit but again would not lead to an unrecoverable coolant loss.
I'm hedging my bets on a "burp" aka air in the system which can happen if the overflow bottle is allowed to get low anytime after a coolant change. Or an external leak which would be obvious through staining, smell and a drop in pressure on a pressure
test hand pump.
Now for some experienced advice. Keep your coolant overflow bottle at it's max mark. It's better to lose a bit of coolant out of the bottle if it gets over full, than it is to draw in air if it's under full. Top it up with coolant as that will generally not evapourate with the heat from the engine bay, whereas water or a weak mixture will over time, just from engine bay temperatures getting high.
What I would do....get a pressure
test done by an independent person other than the dealer. I'd suggest a radiator
shop. Then top up your coolant directly into the radiator and an equivalent mix into the overflow bottle and monitor it. Also
check it after about 100 kms of driving. Remember that the pressure
test itself can induce air into the system.
As for the Colorado being over rated for a 2.8l engine.....more B/S. You've got yourself a good strong rig. I have seen these things wired up with monitoring equipment tow trailer dynes with braked axles to simulate load in very extreme hot
test trip conditions up near Kunnanura. Your van and even the 3500 rating is way within it's safe operating limits. The weak link would be the towbar and chassis/
suspension...not the drivetrain.
Fab.
FollowupID:
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