1.4L KFW - Coolant, Cooling and Heater issues

[JohnoH]

Hi all,

Having a problem with my 2007 Berlingo M59 1.4L KFW (TU3JP Engine).

Since I purchased the car, I was seeing coolant blowing out the coolant expansion tank cap once the car got up to temp after driving around for a bit. 
It would just blow out excess coolant, but ALOT of coolant multiple times as it kinda "cycled" through cooling - I assume this is thermostat opening and closing.

Found a small hole in the thermostat housing, so replaced thermostat housing, thermostat (with a Mahle 89degree unit).
Completed full system flush with additive, buttoned everything up and all looked good.
until it blew coolant again....and again...and again.

Looked like a head gasket. So order a Coolant Exhaust gas test kit (the blue liquid that sits in the thing above the coolant tank and you suck the air in from the coolant take to determine whether it had exhaust gases present).
Tested twice over a 20min period. While the car was warming up, and when it was completely warmed up and both top and bottom rad hoses were hot.
Both times passed. no exhaust gases present.

As a Hail Mary, replace coolant tank cap. Fixed. All was great. driving around for a few weeks with no issues, holding coolant well and maintaining temp perfectly.

First long trip: after 100km the car temp start to creep up, heater was blowing cold air (at max heat) and reached 95degree's, so pulled up to see what was wrong.
It blew an average amount of coolant out, but still had plenty in the tank. everything else looked ok.
Got back on the road after 10mins and the temp went back to normal - high 70's to mid 80's, heater was blowing heat (not an amazing amount of heat, but was definitely heating) and completed another 350km with the car staying at 78 > 85 degree's depending on speed (lots of little towns to go through when you go form 100km/h to 50km/h)

Pulled up for a couple of nights and then the trip back.
It was pretty good for a while, then starts to become hotter travelling at 110km/h 93>94>95>96. Checked the heater. Cold air again.
Pulled up. See what's what. Nothing. No coolant blowout etc. Sit for a couple of minutes. Start back up, hit the road and the temp drops back down to normal running temps.

Then over the course of next 3/400km it did this a couple of times. Sometimes there would still be heat coming through the vents and the temp would be rising on a pretty flat road, no traffic, 14degrees C outside.
Got it home without overheating it, and now trying to work out what it is?

Head Gasket?
Water Pump?
Radiator?
Blockage? Or something still in the system after the flush that's blocking things up randomly?
Heat Exchanger in cabin - but this would cause the engine to increase in temp right?

Got a very large trip coming up in a few months. 500 to 800km per day. rough roads, will be getting hotter by then, so keen to get this sorted early so I know its solid.

Cheers,
Johno

[notsofast]

So part of the system is tending to overheat, while another part is tending not to heat up - suggests a circulation issue to me. Blockage, partial blockage, or faulty pump?  Question though: wouldn't a seized pump bugger the cambelt?

[JohnoH]

So part of the system is tending to overheat, while another part is tending not to heat up - suggests a circulation issue to me. Blockage, partial blockage, or faulty pump?  Question though: wouldn't a seized pump bugger the cambelt?

after a few thinking drinks...
Would a hole/crack in the heater matrix (am I using the correct term?) cause this?
I have a worn through patch on the drivers side carpet that is constantly wet - didn't really think much of it.
If it is leaking, this would explain why sometimes the heat works and sometimes doesn't?
it introduces some air back into the system causing air gaps and temp changes.

Turn the car off then back on may temporarily reseal the hole/crack in the heater matrix and its good for a while?

Can I just bypass the heater matrix by connecting the two lines to the firewall together and see how that goes for an extended period of time?

[brodfather11]

The early models suffered from a leaky heater matrix , symptom's were smell and no heater and wet carpet, one solution was to by pass the matrix in engine bay like you suggested

[notsofast]

If the damp patch is from the matrix then it should feel a bit slippery/slimy (it also should be coolant-coloured, if there's enough there to see).

I disconnected my matrix (in a 2001 model) a couple of years ago. Some things to mention from my experience:

The hose connections to the firewall in my model (and I suspect also in yours) cannot be sourced anywhere and if they're cut off (they won't pull off) it's not possible to reconnect them later, so instead I disconnected the hoses from the back of the engine, covered their ends with aluminium foil to stop wildlife creeping inside, and tied them to one side. Then I created a new loop of hose to join up the connections on the engine. There's not much room to do this without kinking the hose and the exhaust is close and must be avoided. I didn't want the loop to go upwards at all, to avoid creating an airlock, so I sort of wedged the new loop against the firewall, using a short length of pipe insulation (foam) to prevent chafing. Also I don't think my new loop was the correct diameter of hose - I think it was 19mm, which is a metric conversion of an imperial measurement. I suspect it should be 20mm. So it was a PITA to connect, but do-able after dipping the end in hot water and adding washing-up liquid.

That has all worked OK, though hasn't actually stopped my footwell getting damp, as I've found that water is also getting in through the door seals (and possibly windscreen as well). But that's another matter.