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Discussion Starter · #1 ·
I have a t4 issue no mechanic I've spoken to so far understands.
I'm no stranger to working mechanically either but this I do not understand.
I have a 97 ABL 1.9TD T4
Expansion bottle has been pressuring to the point of blowing coolant out from past the cap. Head gasket you'll all say.... van runs fine although little harder to strt. Heater works fine anytime. What I don't understand is I've done a sniff test which didn't show ex gas. The problem sometimes goes away for a few days then comes back. Sometimes I can drive 50 miles and no issue sometimes 10 miles and it's pushing out coolant.
Now the weird bits.... 1st it doesn't seem to use any coolant?? And under high pressure when cap is released the level ends up level with top of bottle.
BUT THE REALLY CRAZY ISSUE..... In the coolant.unfer the cap and blown out over the engine bay is what looks like copperslip under cap. When fluid has dried in engine bay it looks like a dust of copper particles but doesn't feel rough or gritty like metal deposits!!!!
WHAT IS THIS????? I've thought impeller? Heater matrix ? It's not brass it's copper coloured. There's no water in oil. No oil in water. Flushed cooling system and put fresh anti freeze in. Replaced exp cap. Still same.
SOMEONE HELP ME PLEASE!
 

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First things first is the coolant actually circulating , don't know but there should be a small hose near top of header tank you should be getting a steady stream of coolant back into tank
 

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i had this same problem. I was filling the bottle to the top line from cold ect then when it expanded some coolant came out of the back area of the tank, but when i unscrewed the cap boom flew all over the place, I also found a perished hose under the engine what would have let air into the system but only slightly dripped with the engine off . its been ok since..
 

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Sounds like whats getting blown out on the engine is a radweld type product - I cant remember the friggin name of it - begins with a K ? -but it looks just as you described. So at some point theres been a leak and someone has bunged a load in. It's done its job but furred up the system and it's blocked somewhere hence the pressure build up. Flushing has only flushed out the weak spots.

Is my idea I:

Pete
 

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Right the brown stuff is probably picked up from inside the rad. When I had my t4 it used to spit water out of the cap, new cap fitted and all sorted. If your coolant is that dirty it would be worth giving it a flush and replacing with new, you might even find it is crud that is restricting the flow causing the pressure build up. As much as I'm anti euro car parts at the moment they are doing pre mixed coolant for £8.99 5lt when ordered online.
To check circulation of fluid take the cap off run engine and get someone to give it some slight revs, looking into the reservoir you should be able to see fluid trickling back into it :).
My t5 over heated recently and only become apparent when on the motorway driving up a hill. When I checked coolant it was all the way up to the cap. That turned out to be the impeller had fallen off the water pump
 

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Right the brown stuff is probably picked up from inside the rad. When I had my t4 it used to spit water out of the cap, new cap fitted and all sorted. If your coolant is that dirty it would be worth giving it a flush and replacing with new, you might even find it is crud that is restricting the flow causing the pressure build up. As much as I'm anti euro car parts at the moment they are doing pre mixed coolant for £8.99 5lt when ordered online.
To check circulation of fluid take the cap off run engine and get someone to give it some slight revs, looking into the reservoir you should be able to see fluid trickling back into it :).
My t5 over heated recently and only become apparent when on the motorway driving up a hill. When I checked coolant it was all the way up to the cap. That turned out to be the impeller had fallen off the water pump
Wtf were vw smoking when they designed the T5?
 

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Discussion Starter · #11 ·
Awesome replies so far.... yes I've replaced cap. Yes it's had k seal in at some point too.
There is a return flow back into bottle but really only a trickle....
I've bought a new water pump and thermostat and bottle and cap. Gonna try changing all that as well as flushing rad and checking all pipes.
I suppose I should try and get cooling system pressure tested first though eh....
 

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Hmm,
Thats all the symptoms of a furred up radiator, assuming it has to run a while before it happens,i.e it dont do it when only doing short trips of less than 4 or 5 miles?
 

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Discussion Starter · #15 ·
It's had k seal in it for Def. But I took rad out last week when I replaced water pump and thermostat (although put old thermo back in as new one didn't open and I ended up with cold lower hose and more pressure!)
I ran hose pipe through rad and water went in top and came out bottom so can I eliminate rad or could partial blockage cause my issues and how do i
A diagnose it
B resolve it other than new rad!
P's pressure test on cooling system did show drop in pressure.
 

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People bung sealant in to cure all kinds of leaks - heater matrix for example. If the rads out remove the thermostat ( again, sorry :)) and reverse flush the entire system.mif you get one hose that's reluctant to flow you know you are in the right area. Even using something like rad flush would help :*

Pete
 
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