The coolant temperature used to reach the middle of the normal range in about 4 miles and stay there, except when coasting downhill for a significant period. Recently, I have found it can only reach and maintain the normal temperature if speeds of 55-60mph are maintained and drops away rapidly as I slow down. I assumed that it would be the main thermostat, but changing it made no difference. I subsequently checked the operation of the removed thermostat and found started to open at approximately 88 degrees C and was about fully open at 100 degrees C - so that was not the problem. I have checked the pipe from the second thermostat (to the oil cooler) and this does not warm significantly. However, the top hose (thermostat housing to radiator inlet) and top of radiator are warm even though the engine does not appear to have reached normal temperature.
Obviously, there is flow from the thermostat housing to the radiator. The thermostat housing has a connection on the radiator side of the thermostat with two pipes - one from the end of the cylinder head and the other goes back to the coolant reservoir. I'm wondering whether the connection from the cylinder head could be acting as a bypass around the thermostat, but don't know how the plastic tee-piece above the thermostat housing works - presumably, it is intended as a one-way air bleed from the thermostat housing to the reservoir.
I know others have had over-cooling problems, but in this case neither thermostat is at fault - I would be grateful for any suggestions.
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I too have had exactly the same problem as you. Today I drove 20 miles at between 30 - 40mph with the ambient temperature at 37 degrees and it never got up to normal.
I have changed both thermostats, the water one today and the oil stat last spring. Both were genuine Ford parts. Unfortunately I too don't know the function of the tee piece on the housing and can only guess that your theory is right.
I understand there is an electric heater plug in the in the heater pipes in order to facilitate quick warm-up. I wonder if it would also serve the function of maintaining water temperature in cold weather. But, of course, it still doesn't resolve the problem of the leak down the top hose.
As a bodge effort, I was thinking about blanking off the right hand third or so of the radiator which is not directly behind the fan. I do use the air conditioner in the winter to clear the windscreen and would not want to damage either the fan or the system by blanking off too much. Ideally, I would rather not go down this road.
Sorry I can't help much. Just moaning really.
Snip quote - I'm sure you didn't mean to quote all of the person's post you were replying to?
Edited by Dynamic Dave on 20/12/2009 at 02:27
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There is probably no fault at all. Common rail engines are very fuel efficient the problem being that when the ambient temperature is as low as it has been in the last few days, the engine heat output is insufficient to keep up with the demands of the heater. You can check this by opening the bonnet and feeling the radiator after a few miles, you will probably find that its cold because all the heat is going to heat the car, if the radiator it hot you do have a problem.
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This is exactly the problem Bob C and I are experiencing. Having changed the oil thermostat and the water thermostat with genuine Ford parts, the radiator inlet hose warms up within minutes of starting the engine from cold. I took the new one out again to check that it was installed correctly and it was, with the locking lug in the cut out on the housing. I checked the "old" thermostat and found it to be working properly. Today I drove the car 5 miles at between 30 and 40 mph and it only just barely got off the cold peg. The temperature outside was 40 degrees. I have e-mailed two Ford main dealers seeking advice. Does anyone know if Ford UK has a technical department and how to get hold of them?
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I have to admit that my original diagnosis was wrong. Having noticed during the recent cold weather the coolant temperature reached the bottom of the normal band quite quickly after starting before dropping down, I decided that a thermostat must be at fault. Having previously changed the main thermostat to no effect, I changed the oil cooler thermostat this week and now the gauge reaches and remains in the middle of the normal temperature band (as it always has done prior to the recent problem). The warmth in the top hose before the main thermostat opens is obviously not a problem if the rest of the system is working correctly.
yankeesiter - sorry, this is no help to you (unless the oil cooler thermostat has has failed again).
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How difficult a job was it to change the oil cooler thermostat? I had mine done by the Ford main dealer.
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yankeesiter,
Replacement of the oil cooler thermostat would be very simple if the steel pipe leading to the EGR valve was not in the way! The thermostat is held in place by a single bolt and a rubber ring prevents leakage. I removed the nuts and studs securing the steel pipe to the EGR valve so that I could spring the pipe back a few millimetres to provide space to reach through to the thermostat. I also removed from the inlet manifold the plate supporting electrical components (again to improve access to the thermostat). The oil cooler thermostat is quite low on the block and a several litres of coolant will be released.
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I have done 140k in mine and what you report sounds quite normal.
The temp gauge will normally sit just below the middle though in cold ambient it will sometimes be below 1/4 on the gauge in normal drving.
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Bought an '05 Ford Mondeo III in December 2009. Despite cold weather, engine was fine and up to temperature (as far as I can remember) for the first week or so. Last week, it stalled a few times (-15C outside) due to the diesel waxing up. There was no heat in the engine. Temperature gauge never gets off the minimum.
Local Ford garage changed the main thermostat on the advice of the AA mechanic.
- Little change - engine warms up if you absolutely welly the car. As soon as you drive normally, it cools right down again.
Local Ford garage changed the oil stat (on the advice of a friend who is a mechanic, and the advice given on several forums).
- Some change - car heats up after 10 miles or so, but loses heat as soon as I turn the blower on. Car does not heat up from idle. Still feels to be little heat in the engine.
Advice? Is it just the cold weather, and this problem goes away when it heats up? Is there anything else I can get my friendly mechanic to check rather than the clueless idiots at Frauds?
Any help appreciated!
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I cant really help but this is a problem you guys have and its NOT the weather.
I run a Mondeo MKIII 2.5 l PETROL.
It takes a little longer to warm up and then sits in the middle of the gauge as normal, maybe slightly lower. Its -4C outside but the car us WARM.
I can only suggest that you have the system flushed and change the coolant and the thermostats if not already done so.
Water pump?
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Should say that, reading around the forums, this seems to be a problem with diesels - are you sure it's not a problem confined to diesels?
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I don't think it's a problem specific to diesels only Ford diesels. I used to have a 3.0 Isuzu Trooper and it used to heat up to normal in a mile and a half in cold weather and stay there. With my Mondeo (see above), I have tried everything and now have even blanked off a third of the radiator but guess what. It's still the same. If I ever buy another Ford, I'll test drive the temperature gauge
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From my experience of these TDCI they are like other diesel engines, i.e. bit slower to get hot than a petrol, but they do get there in the end. If will not get properly warm, even after many miles, that suggests a fault of some sort.
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Strange...
Ok, new twist on this - problem first crept up in the cold weather with a cold engine. The car stalled intermittently.
Since I've had the thermostats changed, this had not been a problem (just the low engine temperature). Until yesterday when it nearly stalled at 25mph in 3rd gear going up a hill. Engine temperature was at halfway (for once!) and had just changed gear.
Suggestions as to this latest twist?
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Sorry, not really, but I posted a copy of this forum to the Ford dealer that I bought my car from together with a covering letter. I'm not holding my breath but I'll keep you informed if I hear anything.
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I have to disagree with the writer who has a petrol model, this is a problem peculiar to diesels, one of the reasons that the fuel consumption is better is because they are more thermally efficient than petrol engines, i.e. the turn more fuel into power and less into heat, the modern common rail engines even more so. When the weather is really cold the engine is just not producing enough heat to sustain the heater output, I am sure if you turn your heater off the temperature gauge will eventually climb to normal. Feel the radiator, you will find its pretty cold as there is no surplus heat for it to disperse.
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Using the diagnostics tool on the computer described here:
fordwiki.co.uk/index.php/Instrument_Cluster_Self-D...e
...it gives the cylinder head temperature as 77 celcius after a LONG run in the car immediately after pulling over (temp gauge showing normal - halfway up).
I'm advised (by a Mondeo or Ford site somewhere) that the ideal temperature for this should be between 90 and 115 celcius.
Still no word on the solution... any further ideas?
Software problem?
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I have now received a reply from a Ford main dealer.
He confirms that:
1. Overcooling is a problem on this model (diesel)
2. Some success has been achieved changing thermostats
3. Some success has been achieved by changing heater hoses with a restrictor (Ford Finis No. 1417703 £24.99 + VAT).
4. There have been issues with water pump failure.
5. Problems can occur with air locking. Ford can vacuum bleed your system.
If all else fails, you can phone Ford and discuss your problem on 09065-533-447
for a £ a min.
I look forward to your thoughts.
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I'm going to relay this information to a few friends (mechanics) and see what they make of it.
I'm VERY reluctant to let FORD deal with the problem as they didn't seem aware of it in the first place.
Many thanks for taking the time to contact Ford about the problem!
AG
Edited by Dynamic Dave on 23/01/2010 at 13:58
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I did around 10 miles this Morning in my Punto diesel - never went near normal temperature as the heater was taking the heat from the engine into the car. Very efficient these direct injection diesels.
There`s nothing wrong with it - as Peter says.
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Thanks for that. I'd be interested to hear what they have to say. I just got back from Brussels with a third of the radiator blanked off on my Mondeo diesel. It never overheated but it still takes a long time to warm up and never gets properly warm in around town driving.
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My '97 1.8 turbo diesel Escort has a superb heater.
What's wrong with doing what my old Dad used to do in cold weather, put a blind in front of the rad, sometimes almost the whole rad, in cold weather ??? :-)
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The fact that, at idle, the engine never reaches the 'normal' operating temperature, even when the blower for the car heater is off.
Despite the efficiencies of modern diesel engines, if the engine isn't heating up properly (to the temperature that the manufacturer deems 'normal') then I would suspect there is a problem.
If it means paying a little less now to get it sorted, avoiding a bill later for a problem I could have checked earlier, or to avoid excessive wear on the engine then I'm willing to get it looked at.
Also, on cold mornings, it'd be nice if the car could be halfway approaching warm.
AG
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"The fact that, at idle, the engine never reaches the 'normal' operating temperature, even when the blower for the car heater is off."
That`s normal for a direct injection diesel in Winter. You could idle mine for 30 minutes and it would just be moving off the bottom peg. Then it would stay there.
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Ford sell their diesels all over Europe and as someone who has used their cars in northern Norway in winter I found the car heater to work fine.
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I just did an 8 mile trip at speeds up to 50 mph. Temperature outside was 1 degree C. A couple of times and only briefly did the temperature gauge come up to normal. Most of the time, the temp needle was on the first line of the normal zone or just above it. When I got home, the top rad hose from the thermostat was warm (not hot) as was the left side of the radiator but the right side was stone cold. The hose to the water pump appeared to be neither hot or cold. I'm beginning to wonder if my Ford dealer's suspicions about an air lock are a possibility.
Any thoughts??
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I still think you have a thermostat problem. If the stat is working properly the coolant should climb up to working temp and then the stat should open. If the temp of the coolant then drops below working temp then the stat closes again. Basically it cycles open and close to keep the engine at working temp. It is really not that cold in the UK in winter (compared with the rest of europe and scandinavia) so this system should work.
To check out the stat in situ, start your car from cold and leave it idling a moment.
Feel the top of the rad near the top hose inlet.
Get someone to hold the revs at say 2000rpm while you keep your hand on the rad.
It may start to feel slightly warm (due to some heat bleed).
As the gauge approaches normal operating temp you should feel a sudden flood of heat into the rad as the stat open.
If the rad just gets slowly warm and not suddenly hot, then you have a stat partically stuck open.
An airlock will normally cause overheating.
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Although it's not that cold in the UK in winter, don't a lot of the Scandinavian diesel models have auxiliary heaters which may help to alleviate this problem, or certainly mask it to some extent?
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I'm kind of inclined to agree with you except for the fact that I have had 3 different thermostats in the engine in the last 4 years. The last one I removed I checked in boiling water and it appeared to be working correctly. I phoned the Ford main dealer today to discuss the problem further and he reassured me that the way my car worked today was perfectly normal. He also added that forums were a waste of time because people talked about things they knew nothing about and that led to others thinking that they had problems they really didn't. Uuummm.
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Further to this - I (finally!) had my car checked by a mechanic I know and trust - my old man's used him for at least 10 years and I value his opinion (unlike that of FRAUDS).
He drove it a bit. Checked the engine and said that the engine was fine - heating as it should, running as it should.
There is, however, a problem with the turbo - it's ALWAYS on. I'm yet to speak to him to get the exact problem, but he reckons it'll need a new turbo.
Anyone with a bit more technical knowledge have any ideas re this?
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