So hoping someone in the know will have some ideas.

Had a guy come to me after his temp gauge playing up going to the red then going back to half way and the engine being fine and not actually over heating so it seems.

I replaced the Temp sensor as they are a common fault and the problem is still there! So just to be comfortable in my own mind to let him go with the car i changed the thermostat and replaced the whole circuit of coolant with fresh stuff! The gauge is still the same.

The thermostat is a 82c jobby. I have plugged into the OBD port and the engine reads around 120c and once it hits 122c the temp gauge goes haywire and the fans kick in as they should. And temps read as high as 131c just normal driving 60mph on a carriageway.

I would also like to note as anyone who knows this engine will know that the temp sensor is situated in between cylinder 2 and 3 plug in the rocker cover and is no way incorporated into the coolant system so its a Engine temp more than a coolant temp.

The car uses no oil or water and it on around 80k miles and the car itself it on 186k.

Any ideas throw them my way

 

Water pump? Expansion bottle, dodgy gauge?

 

Had a spare cap that i threw on it and was still the same! Pump is a possibility but coolant is going through the whole system and can feel the pipe get hot once the thermostat opens.

Its due a cambelt and pump an its something that will be done in the next few weeks so will be another possible eliminated.

Dodgy gauge is what i was thinking but the OBD port gets the readings from the ECU which is the same place the gauge will so kinda eliminates the dials.

 

Is the system pressurising? Do a sniff test if you can as the head may be crack aswell?

 

Yes system has pressure. Thanks all ideas welcome. Its a pretty simple system until it gets to wiring then im out of my comfort zone

 

The temp gauge is common for going wrong on the focus.

 

Sounds like water pump slipping (might be fine at idle but slipping with a few revs on) to me Ben, if it's left to idle does it get hot quick or only just when driven?

Mini-me (Mr. Bishop) had a similar prob in his old Zetec-S Fiesta which would only get hot on the motorway, trundling around it was fine. Water pump cured it.

Hope you're ok anyway dude!

 

My advice would be get rid of it, My old 1.6 focus had a similar problem,
water pump + Aux belt, thermostat and housing, head gasket, temp sensor, new rad, in car heater was hot so that rules out an airlock if what I was told is true,
nothing cured it.

 

Check first weather it is actually overheating. Use a separate water temp gauge plumbed in somewhere to confirm temperature. Check the wiring loom from the sensor plug backwards as far as you can for damage and chafing.

I remember a long topic on here about this a little while ago about exactly the same issues, could be worth a search.

 

Can check the CHT sensor volts vs temp as follows

Coolant Temperature °C (°F) CHT (volts)
20 (68) 3.09
40 (104) 2.15
70 (158) 1.04
80 (176) 0.79
90 (194) 0.61
97 (206) 3.51
105 (221) 3.25

 

could well be mate! it is due a cam belt change so this could be on the cards sooner rather than later now. it sits at about 105c and half way on the gauge at idle! only when driven it goes up! its been to 132c but fans kick in at 122c all logged from the ECU with OBD reader with new sensor.

Yeah all well and good mate! Should of thought to give you a shout on the old FB. Hope all is well with you too! Get that Golf back on track!!

Only place its going with current mileage and condition is the scrap yard sadly so he is keen to save it! will see what a waterpump does for it as it is due one! cheers

Loom is all ok this is something else i have checked! Another temp gauge isnt a bad shout though to get an idea of what im looking at. It seems a common problem but from what i have read a new sensor tends to cure it or the topics go on for ages with people struggling to find the sensor at all lol

Usefull info thank you buddy! could of done with this today

 

This engine has a cylinder head temperature, not a coolant temperature.
Cylinder head temperature tends to be higher then the coolant temperature actually is.
Before worrying about the high temperatures you need to check what the values normally should be.

 

Ok so yesterday i changed the cambelt and water pump along with another radiator just in case it was a blockage. Ran out of time for the customer wanting the car back but i still had trouble bleeding the system. Not sure if this was due to time or not. I had a feeling it may be the heater matrix as on the fiesta and pumas the heater control valves cause the same problems once shot. So i disconnected the hoses from the heater and connected them to one another to bypass the heater circuit and it still didnt seem to bleed to well.

So anyway i drove it to the customer which is around 7 mile away and when i got there all the hoses were hot and the temp gauge didnt move once all the way and sat at half way nicely. since i stated this thread the engine has been running with an open thermostat with no temp issues but once i did the water pump i put the stat back in.

So until i have another hit at it in the week the question is...

has anyone experienced over heating problems through the heater matrix being the cause in the car?

 

Ben,You have to 'rev the bollocks' off them to bleed them, ask Andy Baker how he used to do it...

Actual Ford method is remove heater supply hose, fill through the hose with a funnel till it runs out of where the hose is on the engine (under the coil bracket) re-connect hose then "Warm the engine up at 2750 RPM for two fan cycles."

 

ok mate cheers. never had a problem with bleeding coolant systems before. will give it more beans. Baker has mentioned it before haha. Just paranoid about that crank bolt now after the belt change fooking horrible things.

 

Well its been done a few weeks now but thought i would update as its always annoying when searching old threads and you cant find the outcome of the problem.

I got the car back and connected up the matrix and bled it again and bled no problems this time i think it was just because i ran out of time before it decided to be a pain in the arse and now he has run problem free for 3+ weeks. Temp issues have stabilized and it is suspected that the plastic prop on the water pump was spinning on the spindle when upto temperature as the cam belt and pump replacement have sorted the problem.

Thanks for your help and tips folks.

 

Good update Ben.

Glad it's sorted.

That is the thing, you very often get threads asking for help but no outcome/fix is added.