water pump problem ? air lock ? rad issue ?

[mike En]

So I've noticed my mk4 2.5di has been running ever so slightly hotter than normal, has been sitting on the "O" of "NORM" on temp gauge but now sits between the "R-M". I felt the rad hoses top one was very hot and bottom was cold, changed the thermostat, old one was pretty old looking but no difference, also the metal water pipe seems cold on the back of the water pump.
After changing the stat I then topped it up while running, squeezing the pipes as i went, it was pumping water out of the pipe on the thermostat housing and in to the front of the header/expansion tank so I'm assuming the pump is working ?

I first noticed a problem when I was sat for 1-2 mins after a drive and noticed the odd little bit of wispy steam, opened the bonnet and seemed to be coming from the right side of the rad, haven't noticed this any more, have checked every time after a drive since then.

It smells like hot coolant after a drive but hasn't actually over heated, cant see any leaks apart from oil from the sump gasket.

Has anyone else had similar issues ? Is it possibly a blockage in the rad ? Rad weld from a previous owner ? (just thought of that as I'm typing lol) water pump damaged and only pumping a small amount ?


Any help much appreciated !

Only owned 1 transit so don't have much experience fixing them yet !

[ricc]

id try flushing the radiator.
remove top and bottom hoses and ideally stick a hose pipe in the top , see if water drops out the bottom or just trickles through or not at all.
with a good flow you can try reverse flushing from the bottom, but its easier and less messy to take rad out and lay it horizontal.

[mike En]

Will give it a flush when I get back next weekend, away working in Milton Keynes so the van wont be used till I'm back anyway.
Thanks for the advice mate !

[Frag]

Sounds like you may have a small leak that's evaporating with the heat....
Poss the rad ?
Does it lose water,any sign of staining under water pump or from bottom of plastic timing cover ?

[Celticbiker]

When I first got my mk5 camper van I had similar issues in that it would only get hot on a run and the temp gauge would drop out and in randomly.
After the years of trying to track down the problem the radiator finally broke while we were away.
Got home using rad weld and bought a new radiator (170 gbp) and fitted it.
After a few false starts regarding filling and air locks, it turns out that the old radiator was virtually blocked letting only three smallest amount of water through.
With the new one fitted it gets up to temperature in ten minutes and stays rock steady.
Hope this helps.


Galaxy S6 & Tapatalk

[shipbadger]

A couple of months back the temp gauge of my mk5 based motorhome went to the top end of normal without actually going into the red. As we were climbing Crickley Hill in Gloucestershire which is steep, seems to claim one lorry at least a day, I was not concerned. I reasoned that once 'over the top' it would cool down. Somewhere outside of Oxford I realised that the needle was still at the top of 'normal'. Pulled into a lay-by and let things cool. Fortunately I always fill the water tank before setting off so four kettles of water later it was back in the expansion bottle! Upshot of all this was a failed water pump and water pouring from it. Thank goodness for the recovery services, second time I had called out Green Flag in a month, but not for the same vehicle.

Not too sure why severe water loss doesn't put the needle into the red. Lack of water around the senser? In future I shall investigate more quickly when the needle hits the high end of normal rather than waiting for it to go into the red.

Tony Comber

[mike En]

Haven't noticed any leaks, or even signs of dried up leaks. I've only needed to top up once the thermostat has been changed, water pump seems to be working, I am doing cam belt and water pump in the new year so it will be replaced anyway.
Going to give the rad a flush at the weekend so hopefully that will fix the issue !

[Jim Archer]

Have a feel of the rad after a decent drive and been idling for a few minutes. It should be hot at the inlet and noticeably cooler on the outlet side, you could feel mine getting cooler as it shed the heat.

Jim

[mike En]

Have a feel of the rad after a decent drive and been idling for a few minutes. It should be hot at the inlet and noticeably cooler on the outlet side, you could feel mine getting cooler as it shed the heat.

Jim

Yeah top hose (inlet) is hot, bottom hose (outlet) is cold, also metal pipe from bottom hose to the back of the water pump is pretty cold, guessing that its not getting water through it and is only slightly warmer from heat soak from engine.
Will flush rad through the morning and see if it helps.

[mike En]

Well, took rad off, flushed it through both ways, shook it all about while full and repeated untill it was running clean, then flushed the engine through from thermostat housing to bottom rad hose, all yucky brown water and then a lump of what looked like clay ! (guessing old rad weld) refitted it all, filled up with coolant, went for a drive to Ipswich and back (60 ish miles all in) still no difference !
Smells like hot coolant, no leaks, running upper normal on temp gauge, top hose hot, bottom hose cold.
Will do cambelt and a New water pump after Christmas and hopefully that will cure it.

[Jim Archer]

Does it show hot on the gauge?

DIs are overcooled anyway - when I turbo'd mine, the only time it got really hot was 'cos I was driving in slow M'way traffic on the hottest day of the year with the winter radiator blanker still in place

If you just have it idling, the rad will run cold at the outlet after a few mins, even after a good run.

Jim

[atleladden]

So what was the solution?
I am experiencing similar situation now and hoping for the thermostat, not waterpump.

If i have very good heat from heater it should not be the waterpump right?