2012 RWD Radiator and bottom hose

[jacksonator]

Good afternoon everyone,

Not had to write a post for a long time.

So I have a 2012 (mk7) Ford transit rear wheel drive medium roof..

Problem was my thermostat was stuck which cause the top radiator hose to leak that's how I found my issue..

Anyway I fitted the new thermostat, replaced the hose and bled her up. It's getting up to temperature and opening the thermostat and running the hot water in to the radiator. I think I'm being paranoid but from the top my radiator is hot to the middle then it's luke warm and cold at the bottom, the bottom radiator hose is cold also. I'm assuming all is well as it's not over heating even when driven hard and it's just doing its job and I'm being a pleb. It doesn't hurt getting peoples opinions though or reassurance it's ok

I'm driving abroad with it so don't want no issues.

Thanks guys.

[tranmx2]

The return rad hose should get warm if the coolant is circulating. As the thermo is opening it is likely the pump isn't circulating the coolant.
The rads do fill with debri. There is a drain - very diff to see/find in situ on the lhs bottom of the rad - when opened you may need to poke inside with a slightly bent wire to remove the sediment - it may require several pokes.
Easier to take the rad off and do it - force water through the rad - with the drain opened - still may need a poke to get the water to flow out.

Did my 2012 a few yrs ago. The A6 showed over temp a few weeks ago - cold rtn pipe - belt was slipping on the W pp pulley. IR temp gun showed 32C on bottom pipe when things worked again.

[jacksonator]

Smashing thank you! I think you might be spot on about the debris in the red, I am going to sort that out during the week.

Would make sense because the thermostat hadn't been changed in a very long time if at all.

Appreciate your reply.

[jacksonator]

Afternoon all,

Just a little update:

Pulled the radiator off, flushed the engine then fitted brand new radiator. It ran up to temperature heater blowing very hot, radiator gets hot.. bottom hose still cold!

I'm not sure where I need to go to next? I took her for a hard drive and the temperature gauge didn't move, blowers stayed nice and hot then I pulled over to check bottom hose and it's still cold.

What's going on?!

[metalworker0]

it's winter ..and its cold .
and you are comparing diesel to petrol.
diesels run much cooler than petrol engines ..plus you have oil cooler

Which means that you have, i think in those engines; 8 litres of oil and a couple of gallons of coolant to warm up, plus you have your heater blowing, cooling it down, so means probably at least 6 maybe 10 miles, or 20 - 30 min driving before you see that hose feeling warm.

Your engine will will warm up quicker without the heater on for the first 3 - 4 miles, if you only do short trips having the heater on is detrimental to the life of the engine, as using it in some or all circumstances in the winter (lots of short trips) will not allow the engine ever to get to running temperature for enough time to get everything hot.

Which will lead to:
Engine wear...because the oil does not reach its operating temperature and is thicker , less seeking .less lubricity
Oil degradation..condensation; water not being evaporated out of the oil
More fuel used

all the best.mark

[jacksonator]

Appreciate your reply Mark.

Just to add with some of your advice, I had driven it for about 50 minutes 70ish mph and the radiator was HOT you couldn't keep your hand on it that's for sure! and the bottom hose was still cold. I would say the bottom quarter of the radiator was cold also but that's about where the exit hose on the radiator is. I did turn the temperature on the internal heater down to cool as it was to hot to keep on blowing hot

If I had a bad water pump it would over heat / leak / pressure the system and I would have cold air in the cab? (I don't have these issues)

Its the 2.4 rear wheel drive I have.

Thank you.

[metalworker0]

I've no idea what's going on, if you drove those miles and it wasn't even warm on the bottom hose ..there must be something happening with cooling or you would have the gauge in the red and system pressurising..
I don't know ..maybe its like my connect were you can get several different varieties and configured thermostat housings to suit year built ..you then could end up with coolant taking wrong route etc if you put the wrong one on .

if the water pump wasn't working ..then it would act like a car of the pre 1930s and would work on the thermo siphon method of cooling..and the bottom hose would be still be warm or hot.

BTW ..if you were conducting all these tests with it just tricking over ..outside in present cold conditions ..the bottom hose will never get hot ...the gauge on the dash may never even get past the first segment even after 1 hour . such is the cooling on these vans.

********************************************************************************************

buggerd "LOCKED" "seized" thermal viscous fan coupling on the fan could cause an over cooling condition

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all the best.mark

[metalworker0]

diagnosing thermal fan coupling .

This is mainly down to experience with them, knowing your vehicle and the sounds it makes

A locked fan coupling will make a lot of extra noise due to the air being moved, you would notice there is a lot more noise from the engine.

In high summer or after fast motorway run, or continued driving in slow moving stop start traffic in summer ..the noise is normal...as the fan is made to lock up in high heat conditions. and provide extra cooling.

In the winter ..there should be hardly any cooling effect from the fan and less noise ..DON'T DO THIS but at tick over in these cold conditions with engine cold, it should be possible to stop the rotation of the fan with you hands.


With a stopped cold engine ..a fan should be freewheeling when you attempt to turn it by hand ..some smallish resistance is present on brand new fan couplings .


all the best.mark

[jacksonator]

I appreciate you taking the time to reply.

When the engines off the fan spins by hand with slight resistance, when the engines running the fan runs fine (I haven't tried to stop it while it was moving)

All test's I have done are with the temperature gauge sat at halfway (90 degrees) when I was doing stationary test I held the revs at 2500k for about 15 minutes and I watched the temp gauge move but stationary or driving the temperature gauge doesn't go past half way. There is no funny noises coming from the engine, the revs don't go up and down or anything she's spot on when idling or driving. Only thing I haven't changed is the water pump but I don't think it needs doing (I could be wrong) not sure what else to try or where to go. I will run it for a few days and hopefully I get an easy ride.

If the system was pressurised my hoses would be hard and my expansion tank would be full of coolant is that correct?

[tranmx2]

If the system was pressurised my hoses would be hard and my expansion tank would be full of coolant is that correct?
What is meant by pressurised? Normally there is pressure in the system due to heat. The pipes feel firm due to the heat in the system - the expanded coolant pressures the air in the coolant bottle/header tank. The header tank vent lifts at 19 to 22 psi. The higher the pressure in the system the hotter the temp can be without evaporation. The guage needle is usually vertical on the consul when the engine is at operating temp which is about 90C. It takes about 5 to 7 mins for the engine to reach operating temp. The ambient air temp and wind speed and rainfall alter the time it takes to get to operating temp.
Cold the pipes are soft - hot the pipes are firm.

The system can be pressurised due to gases from a leak in the head gasket - the pressure caon be a lot higher. The pipes are very firm.

Your system is like this one.

Coolant syst red van txt Pre 10 12 21 (2).png

The thermostat is similar to this image.

Wasther reducer 2 (2).png

The coolant pump is required to - circulate the coolant - helps to give it movement. It is not a pressure pump - it is a cirulating pump.
On the older vehicles with a V profile pulley the pump may not rotate should the belt be too slack and the system pressurised from the coolant heat = overheating of the eng' coolant.

If I had a bad water pump it would over heat / leak / pressure the system and I would have cold air in the cab? (I don't have these issues)

It could overheat if the pump is not circulating the coolant. pressure the system and I would have cold air in the cab? No - the coolant to/from the cab can circulate without the pump fully rotating.
The cab heat exchanger can affect the engine coolant temp'.
It is likely that the coolant pump on your engine is not circulating the coolant- there could be a blockage - rag - internally colapsed pipe. A bit of rag left in years ago can move to a place where it is a restriction.

Chnaged radiator, thernostat, thermo to rad pipe.