focus 1.4 2000 reg. Have posted overheating problem previously but no further forward. Can anyone point me in some diagnostic direction please???
Car runs at 92/94 degress C at idle for ever. If revved up and when temperature then reaches 100C, fan cuts in. On checking under bonnet top radiator hose hot and bottom hose cold and coolant in expasin tank barely warm. When taken out on road and under acceleration temperature quickly goes up to 124C (I think this might be the max reading on onboard diagnostics?) Then when coasting quickly drops back down only to to quickly go back up on further acceleration. If continuing at this temperature exclamation light comes on followed by engine light and car goes into "failsafe mode". .

To-date cht sensor replaced, thermostat replaced, new water pump and new radiator, plus coolant has been changed twice. Hoping not cylinder head gasket failure. No water in oil, no oil in water, no coolant leak, no white or blue smoke from exhaust. Had compression test which showed normal pressure in three out of four cylinders but reduced pressure in one but engine not misfiring and no loss of power, etc. Wondering if it could be airlock and if so have tried to bleed by running up to temperature with expansion cap off. Any ideas gratefully accepted.

 

Sounds like the waterpump to me? (Despite it being new) Is the belt tention ok?

If you had HG problem it would be loosing coolant.

Martin

 

thanks for prompt reply. Was originally thought to be water pump but when old one taken off it was in quite reasonable condition, just a little bit of plastic broken off one of the fins, so replaced with new pump with metal fins. How would you know if belt tension correct?

 

further to above and on discussing with a friend who is mechanically minded am coming to the conclusion that it is not overheating at all but the gauge thinks it is and is telling EcU to go into failsafe mode. Reason being that the temperature fluctuates too fast from 124C down to 100C in 30 seconds and back up in same superfast time which is impossible according to my friend. Could it be the Cylinder Head sensor is giving false readings and why would this be could it have been overtorqued when changed??? Or is it the ECU? Any thoughts very welcome.

 

But why would the top hose be hot and the bottom hose cold if it was just a dodgy sensor?

 

Yes, why does bottom stay cold when supposedly overheating at load? When idling (at a steady reading of 92/94C) both top and bottom hoses are warm and will stay like this for ever, then when you start driving just a couple of miles, especially up hill, temperature reading goes quickly up to 124C and then when you take foot off accelerator goes back down pretty quickly and on ordinary driving stays around 108C and when you stop car to check hoses, bottom hose cold??? Will this ever be resolved?

Thanks to all who have taken the time to reply.

 

As a PS to above. I have an infrared laser thermometer, would I be able to accurately check if the readings in car are correct and if so where do I point the laser to get an accurate reading?

 

The gauge uses info from the CHT sensor, which you state you have replaced! It's not right the bottom hose is cold, this shows the circulation not being what it should!

Normally if this is a problem you will notice running problems with the car and EML illuminated, being that it's a major input for the ECU to run the engine.

Use the cylinder head for your temperature testing (Not the plastic cam cover though)

The impellers are common for breaking up on the pump, due to them being plastic, just physically check the belt tension that drives the pump by hand.

Plus 108 degrees is way to hot, should be in the late 80s, early 90's ideally (The stat opens at 82 degrees)

Martin

 

Thanks for reply Martin. Water pump replaced with one with metal fins. Serpentine belt tension seems fine but will recheck. Also will use infra red therm on cylinder head tonight. Although CHT has been replaced someone at Ford said if you overtorque them they can become compressed and can cause false readings. However this does not explain why bottom radiator hose is cold and only warm at idle? Hose "seems" in good condition.

 

first thing id check with any overheating problem is the thermostat, have had continuous problems with thermostats not working and staying closed and 8 out of 10 its always been the thermostat for me not a sensor or the water pump

 

Your temp readings... I am guessing you are getting them from the dash?

Do as you say and check with your gun this will confirm the temp, I think you have an accurate reading and it is overheating!

Martin

 

thanks boy-race-1. was wondering putting a lower temp one in but may mess up ECU settings? Will check out existing one, thanks.

 

i dont know what it will do to your ecu if you take it out but i take the thermostat out of any engine i use now as i just cant be bothered with the issues from them

 

Stat is new but OP could well have a dodgy one, way to test is to see if you can feel coolant passing through the top hose when up to temperature, if not the stat is stuck closed!

Martin

 

That is a very bad thing to do, not only will you loose your heater, you will damage the engine as it's never reaching it's optimum temperature!

Martin

 

what I don't understand is why the car will idle forever at about 92/93c and not overheat. I thought car engines were more prone to overheating when standing still as no air flow and fan not on?? When I drive and temp goes to 124C and I stop with engine still running temp comes down by about 20c in as many seconds, surely that is impossible, even with fan on. Please advise? That is why I thought sensor was giving false reading.

Tried infra red thermostat but having read instructions it only reads surface temperature and not core temp, so cannot give an accurate reading. Temperature right at the back of the engine on the metal part (behind cylinder head) does read high (106C) when engine idling, but I expect that is where the combustion takes place?,

Having said that bottom rad hose is still cold and only warm when engine idling.

 

you can take the stat out but you need to run a restrictor in its place the lack of movment in the cooling ie why you bottom rad hose is cooler saying to me you have a blockage or big ass air lock dose the heater work have you flushed the system ?

 

i had this before on a puma it wasnt curculating the water that was because of a blockage on the back of the head there was a pipe that ran the expansion tank it was full of s**t once i had it cleaned out it was as good as gold. one question are you getting hot ait in the car

 

yes its been flushed and has had new radiator too. Will look the hose coming from back of head to expansion tank but I think all hoses have been blown through.

 

sorry forgot to mention - heaters working really well,probably because of all the heat that is building up

 

new thermostat fitted today. when brought up to temperature at idle seemed to be working perfectly, top hose got hot, then bottom one - in fact all hoses hot and coolant seemed to be circulating, Temp gauge reading 92/94. Then took it out for a test drive and within a few minutes was showing overheating 108 to 116C) and so came back and checked hoses - bottom hose now cold??? Has anyone had these exact symptoms and cured it? All thoughts appreciated.

 

Logic would suggest the radiator being blocked, but you have stated this is new!

It's along shot but have you tried draining and reverse flushing the radiator? Also how do you define "New", i.e. new to you or new period?

Catch the coolant in some large containers then you can reuse it, if need be.

Martin

 

radiator brand new!

 

Try squeezing the bottom hose with it running to see if you can feel the flow. It obviously is a circulation problem, like a strange airlock or blocked radiator. No possibility the radiator could have got crud in it from the engine?

Martin

 

coolant changed twice and is clean. have squeezed bottom hose when cold (after driving car and i has overheated) as it is soft, but at idle it is hot and hard to squeeze.
Two moe things to try - what do you think?
May try and borrow someone's Focus expansion cap and see if that helps.
Also could be bottom hose collapsing when under suction.

 

take the thermostat out completely and test it, the one you have fitted could also be faulty highly unlikely but it does happen, atleast that way the thermostat is 100% ruled out, as for it still overheating, id take the rad off and stick a hose down it and check flow is coming out as it should, failing that take out your heater matrix and run a hose through that checking its working correctly, failing that pull all the hoses out and hose them, failing that id say you may have a crack in the head/block possibly? and have you checked your oil level? overheating and high temperature readings can be caused by lack of oil in the engine, if none of that works then all i can say is its something on the wiring side or just a sensor that needs changing

 

The caps can cause problems but usually it causes boiling out the tank?

Do the said stat test by removing it, though I believe the stat(s) to be good personally, and also yours is a good idea re the hose theory, that or maybe there is a blockage further in the engine? Perhaps try reverse flushing the engine via the top hose? (With the stat removed obviously)

Martin

 

thermostat checked before fitting (and original thermostat was also working). No oil or coolant loss. After doing the two things I mentioned above I am going to check into a garage next week as it is driving me mad. Will keep posting though whether or not a solution is found. Hoping not chg or cracked head/block. Thanks for your replies.

 

This is usually the small return pipe into the header tank, had to drill a few out, you can flush it out but the inlet into the header can block.
Had a leak recently and used radweld ?

 

Both return pipes to the expansion tank are clear - thanks though for that though bortaf.

 

Won't be a cracked head/block, else you would be loosing coolant.

Tried reverse flushing via the top hose?

Martin

 

Sounds silly, but is the belt on the correct side of the waterpump pulley and not the other side, causing the pump to run backwards.

What makes me curious is that the bottom hose goes cold as soon as the diagnostic display shows the temperture increasing. Makes me wonder if the water is being syphoned out of the lower hose.

 

today's follow up - managed to get in touch with previous owner and they confirmed that they had same problem and had done most of the work I have had done to no avail (wish I had known this sooner)! They said last thing they were going to have done was replace the "clocks" but in the end it was causing too much stress so they traded it in. They had also taken it to Ford and no fault was showing on their diagnostics (same as me). Had also taken it to various garages and they were baffled.

Before getting in touch with them today I let car idle and get up to temperature which is around 94C and will happily idle at this forever with ALL hoses including bottm hose HOT, then took it out for a drive and car onboard diagnostics showed overheat up to 113C so stopped car, gauge went down to 108C, lifted bonnet and bottom hose COLD, when I got back ino car literally seconds later, gauge was showing 98C. Drove back home - total round trip of 1.5 miles and let car go back down to idle temperature of 94C, felt bottom hose which was now HOT again and supposed coolant circulating again???

 

Am now waiting for Ford radiator bottom hose and expansion cap to arrive. \have been reading elswhere on the net about the original hose having a spring in it to stop it collapsing but am told this is no longer the case! Does anyone know about this spring or can one be added??? On the American forums loads of people are referring to this being added to their bottom radiator hose to avoid the problem of it collapsing.)

 

bottom rad hose and new rad cap not solved problem. Am now thinking it is an electrical problem. Going into Ford Garage Monday for an hour's diagnostic.

 

Ford garage said it was probably a radiator blockage and they needed to keep it two days, take radiator off and send it to a specialist radiator company to get it pressure tested. Reminded them it was a brand new radiator just fitted. Said it could still be blocked. Did not agree with this diagnosis so arranged to take it to a garage recommended by a mechanic who had previously worked there and rated them highly.Last resort time. Took it there today got aphone call to say it is sorted!!!!!!!!!!
Not actually overheating, PCM needed recalibration by Ford garage. Collecting car tomorrow so hope problem now finally solved.

 

PCM recalibrated and problem finally solved. Cost Ł50!!! Wish I had known sooner and could have saved ŁŁŁŁŁs. Note to Shaun, tried to send this message to you but your message box is full, apparently?

 

Hi there, I seem to be having same problem. Replaced thermostat and I can sit idle fine for as long as I want. After a few minutes driving it jumps up to max temp. As it stands I'm idling and have Heater on max and no hot air is coming through. But when it jumps to red when driving I get hot air through fans.

In addition the hose to the right of the engine (when looking face on) is really hot but only after driving, idling its not hot. And the one on the left is normal then a little warm after driving.

Engine fans only kick in when jumps up to red line.

Going garage in morning to rule out head gasket but could it just be PCM recalibration?

 

Did you ever figure out what was wrong with focus. We have one doing the exact same thing