Focus 1.6 Petrol cool running in urban conditions

Stu wrote (apparently) in uk.rec.cars.maintenance on Sun 12 Dec

2010 14:32:05:

08 Fiesta Ghia here. Takes near to forever to get warm air through going to work, on the way back from work there is an overtaking lane on an A road just round the corner where I take it up to 5K rpm in third which heats it up within the next couple of minutes.

Compared to the 01 Fiesta Ghia I had before it it's appalling.

Gauge stays the same on mine but if I drop the fan speed from 2 to

1 I notice it cools off straight away, regardless of speed.

Same with previous Fiesta.

Fortunately mine has a heated front screen or it would be pointless going anywhere in winter weather. Think the mirrors are heated too when the snowflake symbol is on on the dashboard.

Anyone else noticed exceptionally warm air coming out of the side of the centre console adjacent to the clutch pedal even when the controls show nothing to that area? I've had my foot hovering to change gear due to the snow and ice and have noticed a heat rash (and felt the heat) when I've got out of the car.

Knackered thermostat.

Thanks for your reply. The heater on mine isn't too bad, what bothers me most is that the engine is being overcooled. Good to know I'm not the only Ford owner with this prob, though. ;-)

Stu

I can think of no other reason myself. But I've had a stuck thermostat before, and the effect of that was the engine ran cold out on the open road when the airflow was at it's greatest. The symptons I have now are the opposite, which is causing me some confusion.

On previous cars I would've just bit the bullet and tried a new thermostat, but I believe with this car you have to buy the complete housing with the built in heating element, which obviously makes the part a lot dearer. I've also got to take the alternator off to get at it, which means I need a new vee belt + fitting tool because it's been designed as single use only with no tensioner - cut off to remove!

In short, it's a relatively big & expensive job just to change the thermostat, so I'd like to be quite sure about the diagnosis before I spend the time & money on it.

Stu

I've noticed it's quite common for cars to run a little hotter on motorways etc. I suspect modern car radiators don't get as much air at speed as in the old days before aerodynamic efficiency considerations.

Another possibility is lack of coolant, so there isn't enough to warm up the heater or get the temperature gauge sensor to register correctly, while your engine is actually probably overheating :-(.

+1 - check your coolant level asap.

I know there are many car owners who don't even realise it should be monitored, but I'm not one of them.

Coolant level is fine and I'm not topping up either.

Stu

Symptoms still point to thermostat stuck partially open.

Tim..

How does that work then?

All of the pulleys are in a fixed position. Correct tension is achieved by fitting the belt over the ancilliary pulleys and then stretching it over the crankshaft pulley with the aid of a tool that comes with the new belt. The tool fits onto the pulley and hooks the belt over as you rotate it. Because the belt is stretched during installation, you can't re-use it. Crap for the owner from a cost point of view, but I suppose it is an effective way of ensuring the belt is always installed to the correct tension.

Following up on the issue of the thermostat itself, I managed to find a Ford service manual which gave a test procedure for electric thermostats. The idea is simple: hook a voltmeter up to the CTS and leave the engine idling. Record the voltage at 1 minute intervals as the engine warms up. Voltage should drop as the temp rises. As soon as the voltage rises back up or fails to drop significantly within a minute, you've found your thermostat opening temp.

So I followed this procedure and the point where the reading stalled came after 10 minutes and a voltage of 1.15V. This corresponds to a temp of less than 70 degrees, so it does indeed point to a bad thermostat. The temp then continued to rise, more slowly, for a further 15 minutes until it finally reached a normal temp of 90 deg.

One other observation I made is that despite the rise in temp stalling early on, the return hose from the radiator remained stone cold to the touch right up until the engine was about fully warmed up. So even though the thermostat may be opening early, it can't be allowing a great deal of flow. I've concluded that it needs replacing but not as a matter of urgency.

Thanks for the replies,

Stu

Like I said, a knackered thermostat. Nothing else really which could cause it when you boil it down.

;o)

I had a similar problem with a Mk1 Fiat Punto a couple of weeks back. Turned out the thermostat had been poorly made and the rubber seal was worn away on one side due to the spindle not being concentric. The seal wasn't being made and the inside of the car rarely got warm. The recent cold snap forced me to change it, which only took a half hour .... which is why I love this 14yr old car.

Ordered the necessary parts. The two new vee belts are costing more than the thermostat housing, FFS! Feeling quite cynical about that, when you bear in mind that only an OEM belt includes the necessary fitting tools! >:-(

Will report if it solves the issue - may be a couple of weeks before I get round to it.

Stu

Fitted the new thermostat and it didn't make any difference. :-(

Can't think of anything else that may cause this issue so I suppose it's just a characteristic of this particular cooling system. So much for fancy electric thermostats! >:-(

Thanks for all the response,

Stu

Hi Stu,

I have exactly similar problem now with my car. Model is exactly same as yours. Did you manage to fix the problem. I would appreciate if you could provide any information on this.

Sumy

How about instead of resurrecting a three year old thread that I doubt Stu is still following, you start a new thread and explain your problem?

Tim

What is an electric thermostat (on a car) I haven't heard of such a thing, why would anyone re-invent and complicate the wheel? The zetec with the thermostat low down on the front behind the alternator is conventional, I have seen and changed them (when replacing the plastic bi-furcated hose connection)

It's an ordinary thermostat with a heater bolted to it (stop scoffing at the back!)

The idea, I presume, is to allow the ECU to increase cooling ahead of a large heat dump. Of my experience, BMW's M54 3.0 petrol has one - a lump capable of generating a lot of spare heat!

I see, thank you, so if it were in the OP car you could just add a switch to prevent it coming on and overcooling. or sort the software.

It also has the claimed advantage of delaying 'stat opening, so optimum temperature is achieved sooner.

If the OP's Focus one is like the Mondeo ones, it's not unknown for them to break up internally, giving in effect a 'stuck-open' condition.

Chris