T5 2.5 axe overheating problem

[Okaruss]

History: Did and oil and filter change on saturday. Nothing out of ordinary except for degreasing and hosing down engine bay afterwards. Have been driving on dirt recently and it was a bit dusty.

Problem: engine starts and runs fine. Drove about 30km from home on sunday towing dual axle trailer. No problems.
Wife drove van home with trailer while I rode my mountain bike. Get a phone call from her to say temp gauge off the scale and alarm going off. She just made it home when this happened.

I looked at it when i got home. Water level normal. Started and run ok.
I drove it to work monday morning (still with trailer) and first thing i noticed was that it got up to temp (90) quicker than normal. It sat on 90 along a flat section of road but at the first slight hill temp shot up to near red line.
I switched on the cabin heater and fan but it just blew cold air at me.
A couple of stops on the way to let it cool down. Fans were running high speed. Top rad hose was quite hot but bottom hose just warmish. Coolant expansion tank was near full to the top and gurgling.
Rang local VW and ordered thermostat. Thinking it may be stuck closed.
Thermostat fitted and test drive result is nothing has changed. Same overheating.

Van has done 208,000km. Replaced water pump at 164,000km. Replaced most/all the other T5 AXE engine related disasters over the last 40,000km as well.

Hoping the T5 brainstrust out there can help me.

[Transporter]

Logically if the coolant is circulating (water pump is turning), is not contaminated, radiator at good condition with unrestricted airflow through it and you put enough engine oil in the engine, it shouldn't overheat. Make sure that the coolant temperature sensors are ok and cooling fans turn on when they should and not when it's too late.
Have you been using correct engine oil at all times?

Did you change the coolant recently? Make sure there's not trapped air and VAG coolant at right concentration.

[Okaruss]

I decided to check what the water pump was doing.
I was hoping the nut holding the gear drive on the front of the pump had come loose and the gear wasn't driving the pump. May have been an easy fix. After taking off the pump cover the nut and gear were in place and all ok.
So now the pump has to come out thinking that maybe the impeller has come off or is free spinning on the shaft.
Below is what I found.


This was a quality german made pump that lasted just 2 years and 44,000km.
The seals were good and there was no play in the bearings.
No marks on the impeller. If the impeller had come in contact with "something" surely the fins would break off before the shaft broke.
Now to buy another pump. But which one. Another German one, Italian, Chinese?

[Umai Naa!!]

Genuine.

[Sunny43.5]

When you say "German" was it original VW or aftermarket just curious . Regardless that's a pretty bad break seems like some problem with the metal compound .

[Transporter]

When you say "German" was it original VW or aftermarket just curious . Regardless that's a pretty bad break seems like some problem with the metal compound .

I doubt that VW makes their own water pumps and if they do their genuine one in the T5 5cyl. engines (in almost any engine really) have a very bad reliability record for a long time. They just leak and need replacing much sooner than one would expect.

You might as well go with the Chinese one, as long as the impeller other important measurements are identical to the genuine w.pump.

I've supplied that w.pump, and would have to find the original invoice to see if there's any brand in the item description. My supplier uses 3 different brands from what I remember.
I've offered to Okaruss to send the failed w.pump to me and I'd try to get the replacement for it, because the failure like this is just not on. Even if the impeller was made from the pipe and not from the solid steel it shouldn't snap like that.

[BrianJ]

One thing that worries me about the way these pumps are driven directly off the gear drive is that there is no rubber or give in the system, it doesn't even have the equivalent of the gates coupling that the alternator has.

What controls the backlash between the gear teeth, is there an adjustment for that, maybe yours was too close and vibrating all the time.

The whole design is a recipe for disaster, the only mystery is why all of them aren't breaking.

Brian

[Sunny43.5]

Yes our original VW pump failed around the 50 -60k mark , was leaking somewhere but never showed up on the ground .

[MultiplexMan]

I replaced mine "just" before it failed ~50k mark. Lots of slop in the bearings. The water pump was a time bomb ticking away...

It helped destroy any remaining faith I had in the T5.

BTW You should have grounds for a warranty replacement for that shaft failure. No witness marks on the impeller to indicate contact or seizure. Fracture implies a defect in the shaft material or a possible stress riser from manufacturing.

[Transporter]

I decided to check what the water pump was doing.

This was a quality german made pump that lasted just 2 years and 44,000km.
The seals were good and there was no play in the bearings.
No marks on the impeller. If the impeller had come in contact with "something" surely the fins would break off before the shaft broke.
Now to buy another pump. But which one. Another German one, Italian, Chinese?

How did you go?
You probably bought a new pump already, but you can send the failed one to me and I will chase the warranty on it. All I need is the months when you bought it from me, so I can find the invoice for it. Even if they only replace the w.pump you could still sell it and recover some money.
PM me or call me, if you need the shipping address.