Escort 1.6 Zetec poor mpg

Firstly what oil was put in- only ever use the correct Ford 5w-30 else you'll have all sorts of problems.Is the car warming fully up- the thermostat may have gone west- temp gauge should ideally be at 3pm although

4pm is ok. Second, check the o2 sensor connector clipped to the rad fan surround for water ingress or corroded connectors. After that you really need the o2 sensor checked for correct switching to make sure the ecu is entering closed loop operation. The degree of mpg loss is just that which would be caused by the engine operating in open loop mode.

Tim..

I really can't understand this fanaticism about precise oil grades. Firstly, there is no such thing as a Ford engine oil - it's just rebranded. My Nissan recommendation is SAE 10W/30 to 15W/50. The optimum grade of oil is very much dependent on average ambient temperatures which are increasing anyway due to global warming. In any case, if you use garage servicing, you have little control over the oil grade or brand. In over forty years of motoring, I've used them all, including straight 30 oil, supermarket oils and all the top brands, and have taken many cars well over 100K miles without problems. Any oil will start to degrade after a few hundred miles and will no longer meet the original specification. The most important factor is regular oil & filter changes and I do believe that current manufacturers recommendations are far too long between oil changes. I certainly can't see why a slight change in oil specification can significantly affect petrol consumption - it's all a myth.

Terry D.

Unless it's a pre 98 zetec :-)

Pre 98 the zetec had hydraulic self adjusting tappets, commonly a garage would put in 10w40 oil and this would cause the tappets to hydraulically "lock" temporarially during their operation, due to the oil being too thick, causing said engine to run like shit. This is why engine oil grade is frequently mentioned when someone asks why their zetec donk is not performing to spec.

This is true, however if you use oil sourced from Ford and you have a Zetec sticking valve problem, it's the dealership's fault, not your own (see below).

Which may or may not be proven, and even if global temperatures as an average were to rise:

(a) the loss of the Gulf Stream would make the UK considerably cooler. (b) seasonal variances mean the argument is diddly squat anyway!

That's not true. You can specify what oil they are to use, if for some reason you don't want to use the default option.

First off, you need to re-read the post - it's not the grade of oil, per se, it's the problems that can arise from using the _wrong_ grade of oil. For this particular donk, sticking valves is the problem. For the pre-Zetec-E variants (i.e. those before the mark two Mondeo, heh), the oil grade is _vital_ - too think a grade and you can cause all sorts of problems.

Mostly yes, and no. I should have correctly said "use any brand of 5w-30 oil". The Zetec engine, especially the early ones were *very* intolerant to an oil thicker than specified- it causes valve stick, running problems and generally very high oil pressure.

Tim..

[Crappy mpg performance]

I don't know. But the guy at the garage said "Oh, that's special oil for the Zetec isn't it?" when I handed the keys over.

Yep this is fine. Sits at 3-4pm when cruising easily on motorway, 2pm when sitting in traffic for any length of time, at which point the fan cuts in.

Nothing obvious here...

Hmm. Any idea how much this will cost - is it worth just buying a new one and fitting it?

Wouldn't the red light next to the clock on the dash do something to indicate this was the case (stay on more than 5 seconds after turning ignition on IIRC)

Thanks for the help!

Robert

Well on the back of my owners manual it says 10W40 (admittedly this was obviously written in by the dealer when the car was new). Those cars in Halfords say 10W40, Haynes says 10W30 (which I can't find

*anywhere*) and the owners manual itself states a variety of grades as acceptable, including all those metnioned so far in this thread. When topping it up I've always used 10W40.

TBH, I don't think it's suffering from sticking valaves or anything like that as the engine sounds like it always did and there isn't a particularly strong smell or petrol or anything from the exhaust.

Thanks,

Robert

The red light in the clock is only the tell-tail for the immobilizer (if fitted) or alarm system (more likely on a 93). Ford never fitted a MIL until

1997 or so, so its impossible to know if the ECU has detected a fault unless you hook it up to a code reader. A failed oxygen sensor doesnt always light the MIL anyway even on cars with it!

Ask your local garage if they have an o2 sensor tester, inwhich case this would be the best plan on action to check whether it is working or not. If it is, next port of call would be the MAF sensor.

I assume you dont have binding brakes or half flat tyres....

Tim..

What's a MAF sensor and where is it? I could check to see if that is corroded etc.

Going back to the o2 sensor. You said to check it for corrosion or water ingress. What would indicate water ingress? The sensor (I am correct in thinking it's screwed into the exhaust downpipe?) just looks blck like it's covered in crud. I noticed the wires come out and are immediatly bent at a right angle by the radiator frame, the cable then trails off pressed hard up agains the radiatior. Don't know if this could have fractured a wire?

Tyres are OK - I always have them towards the top of the pressure range. Brakes. Now that's a moot point. They do squal a bit when goign round corners occassionally, but this is a lot better since I had the brakes serviced some months ago. In any case, all the wheels spin freely when the car is jacked.

Cheers,

Robert

Any wire bent sharply over a period and subjected to heat and vibration is likely to break yes, so check it out. There is a multiplug connector clipped to the fan shrowd where the o2 sensor wire joins the vehicle wiring. Open this up and look for rust, damp, or green corrosion on the pins.

Tim..

Right. 2 of the pins are nice and shiney, and 2 are covered in a white powdery looking substance for about half their length. I can try and clean the pins or just replace the o2 sensor, but how do I make sure that the female pins on the car side are clean? Also, the 'car side' cable is also badly kinked at the connector, there looks to be enough slack to cut the ends off, but I'm not sure it if't possible to re-wire these connectors. Any ideas? I pulled the connector off the air mass meter to check that too, and all the pins on that are shiney.

As an aside, whilst doing this I noticed that the PAS system is pissing hydraulic fluid all over the auxiliary belt and radiator hoses :-/. Seems to be leaking from just about every joint imaginable.

Cheers,

Robert