duratec over heating

[itsawindupuk]

hi guys, ive got my duratec running, but its over heating. Ive removed the thermostat and heated it in boiling water, it opens so cant be that. Its plumbed as follows, the rear outlet comes over the exhaust into the top of the rad, the bottom of the rad goes into the thermostat. The smaller outlet on the thermostat is blanked off. The return above the thermostat is going to the back of the cylinder head as per original. My radiator is stone cold, i checked the water pump when i built the engine and seemed fine. Im using a radiator like a mk1 escort, with the filler neck built into the top. Could i have an air lock? ive run the engine with the cap off to try to lose air if there is any.
Adam

[itsawindupuk]

[rallyrob]

Im no expert but it sounds to me there maybe an airlock.

Or a possibilty the rad is blocked, an old rad can fur up inside if left dry for a long time. I had that with mine years ago.

With a bit of luck someone will be along shortly that actually knows what they're talking about....

[itsawindupuk]

i was thinking of removing the thermostat and seeing how it runs then. Also how can i tell if my gauge for the ecu is reading correctly? It may not be up to temperature yet for all i know?

[bmw02rally]

I also think you have an airlock or blocked rad problem mate.....my Duratec is plumbed exactly the same as yours and although I've only just got it running the top hose warmed up nicely first and then the whole rad plus the bottom hose did once the Thermostat opened exactly when the temp gauge read 80-85 degrees....What thermostat have you got in yours. Mines an 82Degree Cossie one...

Mark

[itsawindupuk]

mines the standard fiesta st one. Im not sure what temp it opens at.

[mexicotait]

Try running it with a hose lose and it should let the air lock out

[itsawindupuk]

not a bad idea that, ill give that a go tomorrow evening and report back.

[dobuy]

yep, mine is plumbed similar to yours, but without a thermostat and I am struggling to get it above 60'c
Never mind summer is on the way!!

[itsawindupuk]

if youve removed the thermostat and it struggles past 60 would it be worth fitting a restrictor in the rad to bring the temp up?

[jimmy2006]

put the thermstat back in and drill a 1/8 hole at the top of the thermstat that will stop any air locks may get

[itsawindupuk]

I drilled a 3mm hole and it did improve. Before hand the rad was cold but after I did that the radiator got hot but still over heated at idle but cooled when I revved it

[Graham]

you have too much coolant by passing the rad, graham blackwell had a whole thread on the subject with his fiesta

[dobuy]

if youve removed the thermostat and it struggles past 60 would it be worth fitting a restrictor in the rad to bring the temp up?

Yep, not too concerned at the moment, as mentioned summer is just a month or two away and with ambient temperatures North of 40 and track temps of 60+, over-cooling will not be a problem.

[itsawindupuk]

mines being used as an every day car so id rather it ran a little hotter. i drove it a few miles last night and it ran at about 75C but it took ages getting there. I still have the thermostat in it so wonder if its overcooling somehow. Is mid 70s ok to run the duratec? if i slow right down it warms up but again if i rev it it cools down again. Weird. I read the fiesta story and mine seems exactly the same as his, but i dont want to lose the thermostat and run the engine cold if im using it every day.

Adam

[rangergt]

I don't have any bypass hose, I just run from the bottom of the rad to an electric pump that feeds into the block where the stock thermostat housing was (no thermostat) then from the back of the head to the upper rad connection. I use a peice of cardboard in front of the rad that blocks 80% of it and I'm able to keep the temps between 180-200 f with ambient temps of -5c to 15c, no problems. I also have a big electric fan that moves a lot of air in a hurry and I have a big rad so summer cooling won't be an issue. I've had this cooling system filled and drained several times with no issue maybe because I can circulate it with the electric pump to work out the air.

[team_zi]

Yep, no thermostat, no bypass hose, no heater. Warms up nice and quick, never overheats, ecu controls the cooling fan, sorted.

Before, with a stat and a.bypass hose it would.overheat at tickover and I needed to rev it hard for the temp to drop.

[itsawindupuk]

today i filled the car up again and not it over heats all the time. on tuesday i managed to drive the car all evening without issues, but now its over heating all the time. Only thing ive done is take the water outlet on the head off to get it welded for a new temp sensor adaptor. Bloody thing, i may just remove the thermostat but im booked at emerald and itll be hard to map.

[itsawindupuk]

ok, i re filled it this time only at the thermostat outlet (little one above the large rad inlet). It now will cool down but only when revved so i look like a complete burk at the traffic lights. If i ran it without thermostat how much damage could this cause to the engine? im not running an oil cooler.

[itsawindupuk]

also, Graham, have you tried, or anybody else for that matter, the caterham type thermostat which is meant to open at a lower temperature?

[team_zi]

I dropped my thermostat in a saucepan of boiling water, and it opened, so I'm 100% sure the stat was OK.

I modified my radiator, turned it upside down, bought a new header tank and moved it from the outlet to the inlet, fitted a radiator swirl pot, and the exact same fault existed.

At tick over, it over heated (+105 C and climbing). Rev it hard, and the temperature dropped very rapidly to around 80C. It was idling at 800rpm, on standard sized pulleys. Standard water pump.

Removed the stat and bypass hose (after spending all that money trying to cure the fault) and it instantly cures itself.

I ran it all summer last year, on hillclimbs, sprints and track sessions, and it never ever overheated.

I wasn't happy that I had to remove the stat in the end, but its done it no harm and I wish that was the first thing I tried instead of the last.

[itsawindupuk]

ok ill try that tomorrow, im just worried about over cooling it and getting it mapped. Maybe ill try with the thermostat removed and keep the bypass hose but with a restrictor to at least allow a little warm water in to try to keep it from being too low?

[itsawindupuk]

Ok I just spoke to retro ford and according to them the engine isn't running hot enough, on the fiesta st the cooling fan doesn't come in till 105c so maybe im switching it off worried it's guna blow when it's actually not hot enough. I'll try running it up to 110, but that's as far as I'll take it.

[dobuy]

Pete McKewan who does all the Duratec development at Raceline reckons anything over 106'c prolonged is a bad idea, some of the alloys start to get a bit plastic at 110.

[itsawindupuk]

i found a website of a guy who built a 7 type car, with the same engine but plumbed the bypass hose into the the small inlet above the main rad inlet instead of the metal one and it worked for him so ill try that too, the hot water should cover the thermostat better that way.