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VT Ecotec - Sludge under radiator cap, NOT under oil cap

sxc_sound

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So, for the past 6 months or so, i have been getting sludge under my radiator cap, but never the oil cap, Car has been serviced twice while its been happing, new oil, filter and coolant, oil was always perfect.

The sludge would be about a 20 cent coin size over about 4 months at a time. So very small amount.

So im guessing the head/gasket is fine as its not in the oil. The radiator and heater core have been replaced while this issue existed. So there wouldnt be built up sludge in the radiator/heater core as they are brand new.

Is it possible the inlet manifold gasket is blown? and will a pressure test prove this?
 

sxc_sound

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Should also note, I know that my rocker cover gaskets are leaking. I have the gaskets just havnt got around to doing it as i plan on putting roller rockers in first
 

D-Rich

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i just went and took my radiator cap off and it had a film of 'sludge'. i have a brand new radiator and brand new coolant its done maybe 3thousand kays since its been in there. so im guessing this is fairly normal.
your coolant doesnt mix with anything it just cruises around the engine doing its own thing. so if you intake manifold was blown the only problem you would have is sucking dirty air.
a pressure test will prove if your radiator is leaking.
hope this helps
 

db_notso

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check transmission fluid is clean if you have an auto cooler in your radiator

only way to know if cooling system leaking would be to pressure test it for long time and see if pressure drops...
 

ch1mp

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that's not all a blown inlet manifold gasket does. i'm getting mine done tomorrow, i have oil in my water and water in my oil. the inlet manifold is letting water into my engine and turning it into sludge. check your coolant stick too. if that has sludge then it's possible it's an inlet manifold gasket. also consider a rusting water pump or something like that. but it's sooo common for an inlet manifold gasket, especially for the age. $550 and they do the gasket, new supercharger gasket and a complete engine flush. probably cheaper for non supercharged.
 

sxc_sound

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i did notice sludge in the overflow bottle on the stick.

Transmission fluid is perfect as is the oil. Im thinking it must be the inlet manifold gasket
 

db_notso

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are your inlet manifold gaskets leaking oil out the back onto tran top and down fron under coil packs
if so do them anyway cant hurt!~
and often where the coolant in the head meets the oil and the inlet gasket i will find white sludge...
 

avanti_rider

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I had the same symptoms in my VT a few months ago. Replaced the inlet manifold gaskets myself and it fixed the problem! No more of this brown sludge building up on the radiator cap.
I also could find no water in my oil, but there was oil in my coolant which was causing this sludge. I was told by a member on here that what happens when the coolant cools down from operating temp, it creates a vacuum effect, and because of the gasket being dodgy, it sucks oil passed the faulty gasket and into the cooling system.

Hope this helps a little.
All up i did mine in about 6 hours with the help of a haynes manual.
Cost of the complete gasket set was about $120 including both ends from holden.

All up with the gaskets, gasket sealer (important), coolant, oil and filter, it cost approx $230 total.
Also, might be worth cleaning out your plenum chamber whilst you are there, mine was filthy!
Cheers
 
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