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1.8 Duratec HE oil consumption and temperature issues. Diffuse symptom difficulties.


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Hello, I've got my second FlexiFuel Duratec HE engined car. First one was an S-MAX, engine (2.0 l FlexiFuel) died at 120ktm after lubrication failure. A reason was never given, but Ford replaced the engine under guarantee.

Six years later, I needed an E85 runabout for a few months, and found a cheap 2007 C-Max with 120ktm on the clock and full service history. The car starts and drives as well as I'd expect from a 13 year old Ford.

After a couple of hundred km, I have noticed the following:

1) The car consumes too much oil (1l per 1000km). At the last oil change, they put in 15W40 instead of 5W30 to try to reduce the consumption. (I know, I know, I will put thinner oil in very soon). I also discovered that the cylinder block had been replaced 60ktm ago (I don't know why, but presumably it was also under guarantee).

2) The engine temp stays below the middle point of the gauge, and the heating only works properly after about 20 minutes.

3) The idle is not very stable, hunting from time to time. Sometimes it will go up and down so much that the engine stalls. I cleaned the MAP sensor, but it made no or very little difference. I also replaced the torn intake hose from the air filter to the throttle housing, and cleaned out the housing - no, or very little, difference.

So I thought to myself that the thermostat and the crankcase ventilation tube behind the intake manifold might be having problems - these are both known weak points of the Duratec HE. If the engine can't get hot enough the clearances are too large and more oil will be getting past the oil scraper rings and being burned.

Today, I pulled off the manifold and thermostat. Here is what I found:

1) The thermostat is OK, the plastic clips in one piece.
2) There is oil pooling in the intake manifold (not loads, but too much).
3) The intake ports on cylinders 1 and 4 are filthy wih oil residue, 2 and 3 are clean. No visible oil pooling at the valve stems.
4) The swirl flaps are in good condition, no issues.
5) The crankase ventilation hose is not porous or torn, and the valve is working correctly (towards intake).
6) I spotted a bit of mayo under the ventilation valve, so I pulled off the oil separator. There was a fair bit of mayo on the baffles (consistency of lard, it wasn't going anywhere). The engine behind the separator was completely clean.

(N.B. There was no mayo visible under the filler tube, and just a touch in the intake manifold oil).

I'm waiting for parts - thermostat and ventilation hose - which I will put in when they arrive. However, I am now fairly stumped as to the diagnosis. One issue that these engines have is that the oil rings get stuck to the pistons. I have found an oil additive specifically designed to help loosen stuck piston rings.

I suppose the mayo on the separator baffles is not unreasonable - any water in the oil would easily condense on the baffles and emulsify with the hot oil vapour eventually.

What I don't understand is why so much oil is getting into the intake. Is the crankase pressure too high for some reason? I haven't checked the compression, but will do so once everything is back together. If the compression is low, what could be the reason, with a (practically) new cylinder block?

Is there anything else I should check or do? I need to drive around a thousand kilometres through central Europe at the end of next week, and don't fancy getting stuck in the snowy wilderness somewhere.

Is the Duratec HE just cursed with lubrication issues, and am I a sucker for punishment? (In my defence, I esplicitly needed a car that would work on E85, and the choices are limited. I already have a Saab (the build quality is on a different planet compared to the C-Max) but I wanted something a little cheaper, lighter and smaller - and more mainstream.

Grateful for any input,
Once Forded twice a Fool...

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  • 3 weeks later...


I'm afraid I can't help much with this, but I'm interested in any replies, as I have almost exactly the same problems with mine, apart from the running too cool bit. I've tried replacing the PCV valve and hose, and renewing the valve stem seals. I'm getting a lot of smoke when I accelerate after a period of deceleration. I'm going to try an oil catch can between the PCV and the inlet manifold to see if that makes a difference, otherwise I think it might be piston ring replacement time :(

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  • 2 years later...

I know this is an old thread but my C max has similar issues , I have noticed the dip stick does not register oil level accurately. I now have 6 litres of oil in sump any one throw any light on this?


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2 hours ago, Steptoefix said:

, I have noticed the dip stick does not register oil level accurately.

Must be a faulty dip stick 🤔

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  • 4 months later...

I've got a 2006 focus 1.8 duratec it started smoking last year .it got so bad that you could hardly see it In the cloud of white smoke it kicked out .on the mot the emissions were through the roof ..so I used 5/30 fully synthetic (  nosmoke ) oil  you drain the oil flush it fit new oil filter and bung this nosmoke oil in and it stopped and passed the emissions test no problem it still losses oil at the rate of about 1/2 litre per 1000 miles .but small price to pay for a relatively little money.this nosmoke oil is a new thing and you can get it on eBay for about £50 for 5 litres .nosmoke oil all one word 

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2 hours ago, diy cheapskate said:

I've got a 2006 focus 1.8 duratec it started smoking last year

That's the problem once they get to 16 they can smoke but just can't buy their own 🤣

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  • 10 months later...

Duratec dip stick works fine in my 1.8 HE flexifuel this way: first out and wipe clean, then in flat side towards engine. Works every time.

My car's handbook recommended to use in flexifuel 5W-40 oil instead of 5W-30. 

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  • 2 weeks later...


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