T5 alternator design=fail..

[Jmac]

the cooler wont let coolant into the oil, if that happens it would be the water pump, i have seen this more so on the AXE motor

Err thats exactly what went wrong mate, coolant into oil( trans), explain how it cant please????? oil cooler can go either way, and explain how the water pump lets coolant into the oil, im intrigued.
Jmac

[vwguru]

Err thats exactly what went wrong mate, coolant into oil( trans), explain how it cant please????? oil cooler can go either way, and explain how the water pump lets coolant into the oil, im intrigued.
Jmac

not talking about the trans oil cooler (quote: (mind you, I would have been even unhappier if it had let coolant into the engine oil ! )
i have seen the water pump seals go and let coolant into the ENGINE oil......

[gregozedobe]

and explain how the water pump lets coolant into the oil, im intrigued.
Jmac

i have seen the water pump seals go and let coolant into the ENGINE oil......

I've read MANY reports of this problem with the T5 5 cyl TDI due to the design of their water pump. IIRC the drain hole in the middle gets blocked, the seal on the water pump side gives up the ghost, pressurizes the central cavity (because of the blocked drain), then the coolant forces its way past the oil side seal into the sump (ie not the pressurised oil circuit).

It was a common problem on 2005 build R5 engines. VW had a campaign to fix all the Touaregs, but T5s were left for owners to fix at their expense once out of warranty (unless they were able to embarrass VW into a "good will payment" by mentioning the Touareg campaign )

If you scroll down a long way in this very long post you can see a photo of the offending (offensive ?) object. The hole in the middle is the hole between the two seals is the one that gets blocked.

http://www.brick-yard.co.uk/forum/wa...opic25489.html

[Transporter]

I'm sure Jmac said oil onto transmission oil circuit.
It looks like the hole gets blocked with corrosion deposits, maybe the cooling systems with the problem were toped up with bad quality water (tap water - chlorine is a killer for aluminium), or wrong coolant. But that's only my theory and the real problem might be something else.

[Shifter]

If the jacket water (fresh water) is correctly treated with the correct amount of chemical (anti freeze) surely corrosion will not occur and the tell tale hole in the pump body will not block.

Should the coolant system be regualrly flushed and re treated with chemical to prevent debris build up and any chance of corrosion??

[Transporter]

If the jacket water (fresh water) is correctly treated with the correct amount of chemical (anti freeze) surely corrosion will not occur and the tell tale hole in the pump body will not block.

Should the coolant system be regualrly flushed and re treated with chemical to prevent debris build up and any chance of corrosion??

As long as you didn't mix different coolants or toped it up with the tap water don't rush onto the changing coolant! I've never had a corrosion or overheating problem on any of my car and 100% of my customers who bought a new car or relatively new car had no problem either.

Always use distilled or demineralised water to mix the coolant with and use only VW coolant G12+.

My van is 5years old now and I'm considering changing coolant in it, but any incompatibility could result in corrosion and other deposits restricting coolant flow in critical areas, which would lead to more corrosion in the places like that Oring on water pump. I will just test the coolant and watch the colour of it and any swelling around hoses and other connections, possibly changing it when the van will be 6years old, ... so far so good.

I change P/S fluid every 2years and it was always very clean, so far no engine oil leak in there.

[gregozedobe]

.......It looks like the hole gets blocked with corrosion deposits, maybe the cooling systems with the problem were toped up with bad quality water (tap water - chlorine is a killer for aluminium), or wrong coolant. But that's only my theory and the real problem might be something else.

If the jacket water (fresh water) is correctly treated with the correct amount of chemical (anti freeze) surely corrosion will not occur and the tell tale hole in the pump body will not block.

The centre part of the water pump (the bit with the drain hole) isn't supposed to have either coolant OR oil in it (have a good look at the location of the hole and the seals in the photo of the waterpump in the Brickyard thread I mentioned above). If both seals worked correctly the centre section would remain clean and dry.

Unfortunately the drain hole seems to get blocked (possibly by grease from bearings or ????), so when the seal leaks on an early R5 motor (note I said WHEN, not IF ! ) the coolant gets into the centre section, it can't escape, so it then goes past the seal on the oil/sump side and gets into the engine oil

IMHO the underlying problem is poor design/materials in both seals. If the seal didn't leak, nothing would go wrong.

If I had an early build (ie 2005) R5 motor with the original waterpump I'd be seriously considering replacing it as a preventative measure, before it leaves me stranded on the side of a country highway with an overheating engine or coolant in the oil (but I'm known to be somewhat cautious).

[Transporter]

The o-ring on that water pump is not moving, it is static, so is the body of the pump and the hole the w.pump goes into. The leak happens when o-ring or surrounding material gives away, since the o-ring is separating coolant and engine oil.

I still think that, somehow there is not enough coolant circulation around the o-ring and coolant stays there without circulation and just rot the small amount of metal away that could happen faster if the coolant contaminated. I saw the pictures and that's what it looks like to me. It would be good to have that failed w.pump in hand for more close inspection
In properly maintained cooling system there should be not even a grain of corrosion on internal parts, of course if it was properly designed.

Another reason to check under the bonnet of T5 once a week.

[gregozedobe]

It would be good to have that failed w.pump in hand for more close inspection

I sincerely hope you never have to find out at first hand on your 2005 build R5-engined T5 (because yours is a prime candidate for this problem I'm afraid ).

[phaeton]

These days sales don't make the money the service/parts do