Dirty coolant dipstick (yellow sludge)

[vc commodore]

Yeah. On cars without a trans cooler, the trans fluid runs through pipes in the bottom mb tank. But, I've never heard of one splitting and mixing with the coolant. Doesn't sound impossible though.
.

Ford Radiators from AU to BF I think had a big issue with this occurring....I've even seen Hyundais do it as well.

Anyways, with the issue facing the OP, I seriously doubt this would be the problem....Trans fluid mixed with coolant doesn't normally turn yellow

 

[Skylarking]

My MSE with < 2000 kms and 15 months since it was built looks just like @chrisp above.

 

[Ron Burgundy]

The smallest leak of coolant can cause this. I read that dexcool does not like oxygen and tends to go sludgee a bit in contact with air...

My car had similar buildup on the coolant dipstick in the first year. I discovered tiny coolant leak on the o ring on the crossover pipe. Negligible stuff.

Holden replaced the o ring and yellow stuff never built up again in 12 months...

I never had any sludge anywhere else...
It could be that this only forms in the overflow bottle as it is not air tight...

 

[Skylarking]

Ah, I get it... Holden doesn’t want us to check our coolant levels

 

[Immortality]

The smallest leak of coolant can cause this. I read that dexcool does not like oxygen and tends to go sludgee a bit in contact with air...

My car had similar buildup on the coolant dipstick in the first year. I discovered tiny coolant leak on the o ring on the crossover pipe. Negligible stuff.

Holden replaced the o ring and yellow stuff never built up again in 12 months...

I never had any sludge anywhere else...
It could be that this only forms in the overflow bottle as it is not air tight...

I'm fairly sure that exact problem was part of the class action lawsuit talked about earlier in this thread. Seems the dexcool formulation probably hasn't been sorted....

 

[tml678]

Ford Radiators from AU to BF I think had a big issue with this occurring

Yep, google 'ford transmission milkshake'....

 

[vc commodore]

Yep, google 'ford transmission milkshake'....

Seen plenty, without googling... Just can't remember when the problem was sorted, if at all

 

[tml678]

Seen plenty, without googling... Just can't remember when the problem was sorted, if at all

From memory BFII had something revised in the transmission which sorted it, could be wrong though..

 

[vc commodore]

From memory BFII had something revised in the transmission which sorted it, could be wrong though..

I honestly can't remember myself, but I'm sure it was revised with the cooler located in the radiator....Then again, you're probably like me, can't remember a lot of things like this

 

[Ron Burgundy]

I had my car serviced today and noticed a bit of yellow build up on overflow hose and in overflow bottle.

I flushed it out and toped with clean dexcool.
Funny thing is that the inside of overflow hose has significant buildup of crap.

This really confirm that dexcool still has issues with air and it tends to sludge.

I am thinking of flushing the entire cooling system and replacing with a different coolant.

The car done 45 000km

I am just not sure which to use. I was looking into penrite stuff...Their red coolant