Strange issue with the cooling system

[SpaceDawggy]

Morning all,

Had an issue with my T25 1.9dg yesterday.  The van had been to a VW specialist to have the coolant pipes running from the engine to the radiator replaced with stainless steel ones.  Work was completed a couple of weeks ago, I drove the van home, then at a later date filled it up with fuel.  Sum total of 14 miles perhaps, across two trips.  No Issues.

Packed the van up yesterday, drove about 3 miles, the dash water temp sat mid way as usual. Then all the sudden water warning light on and also the temperature shot up.  I stopped within 100 meters of this happening and call the guy who replaced the pipes.  Hopefully no damage done.  At the side of the road there was coolant in both the expansion and filler bottles were ok.

Anyway, the van back was towed back to the VW guy yesterday within 30 minutes of this happening.  My other half picked me up and I received a call a couple of hours later to say they put 2 ltr of coolant into the system it was tested and all is ok now.

When chatting with the VW guy at the garage it was suggested that perhaps the thermostat had stuck shut?  Or, maybe some other intermediate issue.  I did drive the van home 3 miles, no problems.  

I replaced the coolant myself 4 years ago (sorry not every two years) and the thermostat (that was fun) at the same time.  To bleed the system I put the front of the van on some high ramps and basically filled it up.  I have had no issues since, only done about 2k miles since , but the van is only used for short trips.  So no issues until the pipe replacement.

So, assuming the VW chap did a good job of bleeding the coolant in the first place.  I'm just wondering if I should now check the water pump just in case its on its way out.  Or, if there is any other reason why this could happen apart from it not having enough coolant in it after the pipe replacement.

I'm just wondering because 2ltr of fluid was put into the engine I'm assuming it was not filled correctly in the first place and might have caused an air lock near the pump?

I'm now paranoid the temperature went high very quickly and if it would have happened on a main road I would be that guy causing a traffic jam.

So, I'm just wondering what to do, trust it's ok now, or get the van nose up again.

Any thoughts? 

[slowcoach]

It probably just still had air in the system. They're a bit of a sod to fill up, and it takes a few decent runs out to push all the air around.

Sent from my Pixel 4 using Tapatalk

[Stesaw]

Make sure the heater is also on full when bleeding.
Put the nose down! Water goes to the lowest point so raising the front of the van up is a bad idea... makes bleeding it a "bar-steward" at least in my experience. Remember there is the bleed valve on the thermostat (if a late setup) or on the main large pipes if early.

To be fair just put it on the level. Get it warm or go for a drive if you're confident there's enough coolant in, feel the radiator if it's hot all over you should be fine. If its cold in places will still have air in. Revs to 2k open the bleed valve on the radiator it might bubble and throw coolant out a bit but it will shift the air out. Check the radiator again if its fully hot all over you should be fine. If the heater also blows hot all the time you're OK. If it goes hot cold hot cold you will have air in the system still.

Just keep an eye in the coolant levels. The main tank with the dalek cap should be full when cold and the one behind the flap should be at max.. when cold too.