The mondingo is blowing out cold air out of the air vents.

I have tried it with aircon on/off.
moving temperature from cold to hot and all fan settings. Its the digital climate control model rather than manual “knobs” and “sliders”

on a 175 mile journey yesterday the car warmed up by driving it hard. Then if you drop to “normal” driving it cools down.

In the morning I am going to check the coolant level.

It hasn’t had anything played with and is standard car.

It was working fine.

Any ideas?

Cheers

Check the coolant level in the morning 🙂

Thermostat ?

Head gasket – Check coolant level. Check for rock hard water pipes when engine is warm. Check for milkyness in oil. Check for oil in water.

Check your wallet.

I will do that.

How will I know if the thermostat is not working/Sticky?

The car is not overheating on the gauge.

Could the water pump be causing the issue?

Ta

Druid- The matrix :-)? Are you suggesting a valve has broken?

Ill check all the water/oil levels and have a look what is in there. I hope that I dont have a car full of milk. I am thinking all of these, but wondered if the car has a common problem. Electrical or servo assisted doors for air flow etc?

Head gasket or cracked head.
Any pressure/frothing in the coolant system?

edit: it’s not a milky water in the oil thing – it’s an exhaust gas in the coolant thing. Forces the water out of the heat exchanger so it doesn’t exchange heat.

Does the engine temperature gauge show that the engine gets up to “normal” temperature or does it stay in the low/cold regime. If the latter then I’d suspect the thermostat is stuck open. Obviously check the coolant levels and the oil filler cap as well!

Right.

Checked the coolant level. It has water in the expansion tank but only at the minimum.

The oil is oily and has not emulsified.

My thoughts now are that there may be a small hole in the radiator or a small leak somewhere else in the pipework.

any other thoughts

From your description it does not seem to reach operating temperature or if it does it takes an age, I’d look at the thermostat first.

If it’s not loosing coolant, smoking badly and the oil is not emulsified then I’d change the stat first before anything else.

Does it reach normal operating temperature on the temp gauge ? Or stay reading cold (or low anyway) has this been more evident with the very cold weather ?

The temperature is operating normally.

The expansion tank has a dribble of water in it. Its not on the minimum. Bad description.

The cold weather has highlighted the problem. Normally gets up to hot very quickly.

You say the car warms up- do you mean interior or engine? Some people are looking at an engine/cooling fault but if the engine temps are running right that doesn’t seem the obvious direction to me.

The engine, seems to me, to be getting to temperature on the gauge on the dashboard.

The interior is cold. Its not hot but on a 175mile journey it warmed up after along time at high speed motorway. Only warm. Drop the speed and it went back to cold.

Oh.ive done 60mile in it today. Didnt warm up. But hasnt blown up.

Northwind, after thinking for a minute it probably is taking a bit longer for the “engine ” to get to temperature in these conditions.

Sound like pressure loss in coolant, possibly the stat more likely the former. Hard to tell though, in this cold a modern diesel wouldn’t boil up anyway. Doubt its the head gasket, & doesn’t always manifest itself as milky oil anyway. If the pot jackets gone water would seep into the pot, but you’d notice lots of bubbles in water. First thing a garage would do (after checking hoses), is pressure test on the coolant system. Trying to think how you could do it yourself but you’d need a gauge. Put a bottle of food dye in the water & run it A bit, then have a good look all over. If heater matrix you’d probably smell it. Could be water pump.

And check out talkford, used to be the Mondeo owners site. Plenty of savvy chaps on there.

Friend had exactly same problem on same model.
Changed thermostat,easy few minutes job,and problem solved.

Um, heater matrix?

Change the thermostat first.

Water pump drives are a problem on these engines. They’re driven, via splines off (which wear) the power steering pump. Also check the power steering belt & tensioner.Having said all this, any water pump issue and i’d expect overheating as a symptom.

As above, only time it happened to me I had virtually no coolant in the car

In absence of other nastier symptoms, almost definately thermostat stuck open. It could have been stuck for ages but it takes some proper cold weather for it to make itself known.

It’s a cheap and (model dependent) easy to fix, so definately first point of call, only a little money wasted even if it turns out to be something worse…

I think its a faulty heater control unit.
My 03 Ghia X has the same heater controls and sometimes blow cold, will blow hot air when on full hot, you can then adjust the temperature down, then it will suddenly turn cold.
This is a intermittent fault and has been going on for years!
Oil levels, coolant levels and thermostat are all good

I think its a faulty heater control unit.

It could be, but that sounds complicated, and therefor expensive. best to check out the cheap, simple stuff first, especially when the sympoms fit so well.

Thanks to all that are posting. Really helpful suggestions.

I am going to refil the coolant level to the correct height in the morning. Run the engine then see where I stand. I think I have a very slight leak. Which is causing air pockets perhaps??

I have looked on talkford, and there is information overload.

I am going to refil the coolant level to the correct height in the morning.

good place to start, but if you have any coolant in the expansion tank at all then its very unlikely that you have an airlock. coolant at minimum level in these ambient temps isn’t too suprising anyway, due to thermal expansion/contraction. Get that thermostat changed man, Stat! 😉

I had the TDCI engine in a 04 Focus. I had the same problem, no hot / limited hot air, taking ages to heat up and the engine fan cutting in more often. I eventually realised I had **** all coolant.

The Thermostat was leaking / weeping coolant. New thermostat fixed the issue. Look for coolant stains coming from the thermostat.

Mega!! I will get one asap. Lets see what the morning brings.

Thermostat, there are two on the diesel Mondeo, it will be the one near the inlet manifold. Easy job and about £25 for the part

I doubt it’s a stuck thermostat.

If the thermostat was stuck open, it would take an age for the engine to get up to temp, most of the time it wouldn’t even get to normal temp the needle would sit a bit to the left of the centre.

I very much doubt it’s a coolant leak, with the milage you have covered you’d have run out of coolant by now, when the car is running the coolant system is pressurized and any small leak will result in the level dropping fairly quickly.

It won’t be the headgasket either, the engines in those cars are terrible (no offence) but they vary rarely do the gasket even when run without coolant.

I’d put my money on the heater control valve. It’ll be bolted to the bulk head at the rear of the engine bay with two rubber hoses going into it – these hoses dissappear as they go inside the car into the heater matrix. The valves are a common failure on Fords.

Ross.
Mechanic.

It’s blowing cold, doesn’t the valve failing normally leave it stuck on hot?

It can be either, depends what setting it was on when it failed. I’ve seen them with the pipes clean broken off too, the housing is just plastic.

From the OP’s description it sounds like the vavle. If the car is getting up to temp normally, not running too cool then it won’t be the thermostat.

Mk3 Mondeos don’t have heater valves. Agreed it is a common fault on the Fiesta and Ka.

How can it not have heater valves ?

If the car is getting up to temp normally, not running too cool then it won’t be the thermostat.

This is true, but a lot of more modern cars don’t actually have a real temp gauge as such, just a gauge that reads cold, then goes to normal when at all warm all the way to almost too hot, then only reads ‘too hot’ when there’s an actual problem. The thinking behind this is to stop people worrying about the natural fluctuations in engine temp that are normal, like towing up a hill, or giving it death on a summers day.

so the OP might not know whether it actually is getting up to a ‘proper’ operating temp.

I don’t disagree that it may be a valve stuck though (unless thy dont have them as the poster above says) just that thermostat is a good place to start.

How can it not have heater valves ?

Coolant runs through the hater matrix constantly,cabin temperature is controlled by a flap in the heater box.

On what cars ?

Everything i’ve ever worked on has a temp sensor in the thermostat housing, or on the head and sometimes another in the radiator inlet pipe. As the coolant temp increases the gauge will increase in either:

The needle going up on a traditional setup.
Increase in bars on digital type setups.

Some cars don’t have any gauge at all, Astra 05 + and Ka’s have nothing just a red light that comes on if too hot.

A mk3 mondeo definetly has a normal temp gauge, bottom left of the dash.

[/quote]Coolant runs through the hater matrix constantly,cabin temperature is controlled by a flap in the heater box

The hater matrix ? 😆

Aren’t the 2002’s known for the flap sticking ? sorted with a torx 25 IIRC ?

A mk3 mondeo definetly has a normal temp gauge, bottom left of the dash.

Fair enough, I don’t doubt it. But I do know that my car (oldish Merc) looks like it’s got a proper temp gauge all needley and everything, but all it does is say cold, normalish range, or overheat. three positions, no way of knowing if engine is the cool or hot side of normal. It acts like a normal gauge, rising slowly, but once there it shows NO variation between a cool idling engine in winter and a hard labouring engine towing a trailer up a hill in the height of summer.

I concur – when I was looking into a similar problem on a previous car I read that if the temp was in the range (something like 75 – 105c) the guage would always be bang on 90c

(maybe the range wasn’t quite that wide)