04 Focus - Temp Sensor In Red & Loss Of Power - Electrical Problem?

[zzz]

just to update you guys.

finally had the chemical/sniffer test done & it was confirmed there are no combustion gases in the coolant tank.

the mechanic also had a handheld laser temp reader & confirmed all the pipes where at a similar temp (70 degrees I believe)

he mentioned the coolant is flowing therefore no blockage in the radiator & there is no air lock in system.

based on the all work that has been carried out so far he suggested it could be either or the following:

- dirty earth contacts

- faulty wiring leading to temp gauge or faulty temp gauge

- possible crack in engine head

the next step suggested is to locate, remove & clean all the earth contacts in engine & maybe get all the coolant hoses physically checked.

[artscot79]

if the head was cracked the coolant would have boiled away to nothing quite quickly bmws are bad for cracking heads so given all thats been said it sounds like a wiring issue to the sensor which is giving a false reading making the ecu believe it has to go into limp mode to protect the engine the loss of power is because two of the pistons are acting as air pumps

[wase16ll]

its all getting a bit confusing this one...never easy to diagnose over the www, but im not convinced with the cracked head theory, would still expect gasses or as artscot said the system boiling over.

was suggested earlier that power loss is no longer an issue, just the jumping into the red but only when travelling at speed after 20mins or so...at which point fan would then cut in..

that suggests to me a blockage, not convinced that checking temp of hoses is proof enough that coolant flow is fine especially when the problem only occurs at speed, you would only need a minor blockage for this symptom your experience...

if it turns out there is an electrical problem, then it has to be related to the temp guage, giving a false reading...but that could be hard to prove...suggested the fan cuts in before it boils, so bringing the temp back down, which could mean the fan is cutting in as normal but the guage is suggesting the engine is hotter than it actually is....

if the guage returns to its normal rating once the fan has cut in, then cant get my head around this being electrical...if the guage drops but stills sits higher than normal then even though ive not heard of a problem like this, it could be possible in theory...

guage works by an earth return, ie..if you earthed the temp sensor wire, guage will shoot straight into red....if there is a problem with this circuit such as a short, its behaving very odd, would either expect it to shoot into red and stay there or drop to zero???

as said, diagnosing over the www doesnt compare to hands on, but this is still screaming a blockage/flow problem to me, its the only thing that makes any real sense of your symptom

your very first post stated this problem started shortly after a flush of the system...was this flush done for a reason, or just to renew the coolant.

beyond that, as i suggested at the beginning, i would concentrate on finding out if the temp is actually rising or wether your being fooled into believing it is, by the sound of it, all mechanics have only checked this car in a workshop, when it doesnt overheat...it needs someone to drive it till it hits the red THEN check if the temp is consistent throughout the system, or giving a false readout.

[FOCA]

Here is a temp gauge you can fit for £13, it will tell you the ACTUAL temp of the coolant, in "real time" while driving,

http://www.ebay.co.uk/itm/2-52mm-LED-Oil-Pressure-Water-Temp-Volt-Tacho-Tachomete-Gauge-Meter-Temperature-/281117979440?pt=UK_Other_Clothing_Protection&var=&hash=item4173eff330#ht_5332wt_1004

Apart from telling you the actual temp (it may not be running as hot as you think) it can tell you if you are getting a false reading from the cars' existing temp gauge, saving a lot of time/ money and avoiding un-nessesary work, or buying parts you don't really need, its all a process of elimination

you could tap it into the heater line (so it works before the thermostat opens) - you will need one of these -

http://www.ebay.co.uk/itm/Motorsport-Quality-Water-Oil-Temp-Gauge-Fitting-Kit-19mm-1-8NPT-103-E-/281119998414?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item41740ec1ce#ht_508wt_932

thats expensive - i modified one of these for mine -

http://www.ebay.co.uk/itm/Hose-T-Piece-Joiner-Connector-3-4-5-8-19x16x19-19mm-/320975734369?pt=UK_Cars_Parts_Vehicles_Other_Vehicle_Parts_Accessories_ET&hash=item4abba50661#ht_714wt_932

my gauge/ s - (hidden in ashtray) top (digital) water temp bottom - voltage (can also show oil temp and control rad fans with adjustable temp) -

switch on left is to manually switch the electric (racing) waterpump - white analog gauge is for boost

the reason im showing you this is if you got one of those (combined) fan controllers/ temp/ volt gauges, you could keep an eye on the (actual) water temp, and be able to electronically set the radiator fan to come on at a lower temp than normal,(might help your overheating) it even includes a voltmeter,(in one neat little package) - i paid about £40 (for 1)

[DeanRich]

Hi I am having the same problem! Did you get your car sorted in the end, thanks