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How to sort out overheating on 1.4i non-AC
#1
This is for the non-AC version of the 1.4i engine in the Mark I Berlingo.
(Until someone supplements the info or confirms that it matches other models)

First, the cooling elements:
There's a water-pump on the righthand side of the car, mounted on the side of the engine-block facing rear. This is driven by the the timing belt. Two hoses leads to it; the thickest is from the radiator, and the narrow is from the heater.

From the pump there's a hole directly into the block...
which is pretty much hollow to let liquid circulate freely round the outside of the cylinder walls, until it gets to the Thermostat housing.

The Thermostat housing sits at the lefthand end of the engine, towards the front
There's three thing to notice about the housing:
1. It houses a Thermostat (accessed by removing 2 screws)
2. A small brass bleed-screw.
3. There are 2 hoses connected to it. A large hose that goes to the radiator, and a narrower that goes to the heater.

The radiator has a fan in front of it, a bleed-screw(plastic) on top close to where the hose from the Thermostat housing connects, a thermo switch fitted below the hose, and a drain plug at the bottom on the same end as the hose.

On the other end of the radiator is the reservoir and fill-cap, and finally, at the bottom is a hose leading to the water pump.

The Heater is a small radiator and fan mounted inside the dash. Please notice the plastic bleed-cap on the 'knee-bend' connecting one of the hoses to it.

There are TWO circulatory systems in this setup:
1. Through the radiator. This is only active if the thermostat is open.
2. Through the heater. This is ALWAYS active.

The thermostat closes off the opening to the hose leading to the radiator until the water reaches a temperature around 90degrees C.
Unless its very hot, the circulation through the radiator alone should be enough to cool the liquid sufficiently, but if the water temperature climbs further, the thermoswitch on the radiator will activate the fan for additional cooling.

What to look for first if it overheats:
1. Trapped air. Bleed the system. This is a bit more difficult than it sounds as air can be trapped inside the engine. Park the car on an incline, or jack up the lefthand side to tilt the engine sufficiently that trapped air moves to the top of the thermostat housing.
Check all 3 bleed screws! run engine a short while, then check again.

2. Faulty thermostat. bleed off some of the liquid first(2L should do) to bring it below the level of the thermostat. Remove the 2 screws holding the hose fitting in place to expose the thermostat.
Test it by placing it in cold water and slowly bringing it to a boil. It should open before it starts to boil. If not, replace with a new. Then bleed the system.

3. Boiling on very hot days. Check that the fan spins easily. If it doesn't, replace with new, or try to fix. Test that it runs when power is applied.
Remove the plug from the thermoswitch, and short the two pins in the plug. This should activate the fan. If it doesn't, check that one of the two pins is at 12V in relation to Ground, such as the engine block.
If no 12V is found, check fuses and cabling. If 12V is found the problem is the fan itself and it needs replacing.
(Some models may have a relay mounted on the fan housing, which can also fail. I don't think this is on the Mk I Non-AC 1.4i, though)
If the fan activated when you jumpered the connector, but doesn't when the engine overheats, check the thermoswitch.
Remove it from the radiator(emember to bleed it down first?) and hook up an ohm-meter to the connector on it. You should read 'infinite' resistance while it's cold. Place it in water and slowly bring to a boil. It should switch to low resistance before boiling temp is reached. If it doesn't, get a new one.

Getting it home to fix it...
Do NOT BLEED! If the engine is hot, the liquid will superheat and turn into STEAM. This is bad if you happen to have your hand close to the bleed screw... Very bad. If you can, let it cool down properly, then add liquid and bleed normally.

Run the heater at MAX. Max heat and max fan power. This will draw as much heat out of that circuit as possible(remember, this circuit doesn't have a thermostat so is always open)
If only cold air comes out, it means there's air trapped in the system.
Stop and bleed!

Running at as high a gear as possible, at as low revs as possible.
The faster you drive the more air is forced through the engine compartment, the better cooling. A good downhill can do wonders...

For God's sake, DO NOT kill the engine!
The moment you switch the engine off, you stop the water cycling. If it was on the verge of boiling, it WILL boil off. If you can idle it with the front into the wind, that may allow it to cool off a bit. Really.
Letting it roll to a stop is better than braking.
Think 'Hypermiling' in everything you do.

If you have to stop the engine, but can spare a few minutes, keep the fan running, and every 30 seconds, start and run the engine for a few secons, so that more hot coolant is cycled through the heater, the heat is bleed off, and the coolant circulated back to the engine.

Is there anything else that can make the engine boil?
Yes...
A leaky water pump will do it, eventually.
I have seen the back of the water pump crack, but this is rare.
(Do NOT disassemble the back. not only is it a pain to reach, but you'll need an O-ring of an uncommon size, too)
If it starts leaking, though, it needs replacing soonest as the bearings are in danger. And when the bearings go, the timing belt also goes.
Always replace the pump when changing belt, just to be on the safe side.

A leaky radiator hose, of course. Or a leaky radiator, or heater.
Those are all pretty evident, though...

A leaky radiator cap can also screw you over. (There's a gasket that can fail, and in the cap, hidden in the center is a valve that's supposed to open at 1.4Bar pressure)
A quick check, when the engine is cold, is to squeeze the top radiator hose quickly. If the cap is leaking you'll hear the air at the top of the reservoir being expelled.

A clogged up radiator can really mess you up.
Try removing it(disconnect hoses and the thermoswitch leads), then it's just a matter of two clips on top to release it and lift it up.
'Reverse flush' it with a garden hose. (Stuff the end into the bottom hose mount and turn it to 'soak everything nearby') You should have a good flow out the top hose mount.

If the flush reveals 'brown goo', you may have a blown head gasket.
(some goo may accumulate over time in older engines anyway as nothing is perfect. )

A blocked heater will also cause problems because it won't allow liquids to circulate through the engine until the thermostat opens. This means the Cylinder head will reach a very high temperature before enough heat reaches the thermostat and circulation begins. If this is suspected, remove thermostat if the car is to be driven for more than a couple of minutes.

Old hoses can also cause problems if they've softened up too much. (They cause uneven flow)

The bottom hose is fastened with a bayonet style mount. You should only need to pull the locking clip(on the outside) and the hose should come right out of the bottom radiator tube. If it's difficult to pull, the seal will have expired and swollen up because of oil contamination.
This seal has part number 1343z4 at Citroën and 2001343z4 at Peugeot.
Feel free to give it a slight coating of dishwashing liquid when assembling the joint.

And finally, there's the THIRD cycle, which no one really thinks about.
The engine oil. This cycles from the bottom, via the oil-pump up and over the head and back down to the sump.
In that cycle there's an oil-filter... I that clogs the oil will not circulate properly, and the head will not be properly cooled.
In these cases, you may also notice that it lacks power at high revs as it gets closer to boiling.

In these cases, the oil light may blink now and then.

It may be the pump itself, or the 'strainer' used to suck up oil from the sump, too. Easiest way to test is to get hold of a pressure gauge, remove the oil pressure sensor(near the oil filter) and connect the gauge there. A working pump should read approx 4Bar when the engine is running at 3500rpm.

The pump itself is listed as 'pull the engine to remove part' repair in the Haynes manual. The pickup and strainer can be removed if you put the car on jackstands and remove the sump. Then it's 5 screws and mind the spring that tries to escape, to remove it.
Check the chain driving the pump, and the two interlocking cogwheels (revealed when removing the pickup and strainer) while the sump is off.
If the chain or the cogs are damaged, though. OUCH...

Whatever you do, remember to dispose of coolant safely. It's poisonous. And because of the slightly sweet smell of it, animals will often try to lick it up or drink from it.

Did I get everything?
Comments?
Corrections?
[+] 6 users say Thank You to Gadgetman for this post
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#2
Thanks for that.Would you like my cure for writers' cramp?:whistle:
Strawberry flavoured windows  Dodgy
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#3
Added a bit about leaky radiator caps and blocked heaters.
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#4
(22-04-2014, 09:03 AM)Gadgetman Wrote:  Added a bit about leaky radiator caps and blocked heaters.
Do you know how it is on a Berlingo Multispace 2010 1.6 Diesel with AC ?
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#5
Nope... but lend me one or a year or two and I'll find out...
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#6
Hope you had a secetary typing that out for you!
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#7
Nope. And I don't even touch-type...
(Learned to write quickly on keyboards back when my most important computer was a Psion S3a)
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