I’ve been having a few issues with getting any tempreture into the engine when driving. I noticed it first at IVA but didn’t really think to much
about it. To get the emmisions passed we had to switch off the test centres fan as the ecu was reading the coolant between 75-80 degrees and started
over fueling the map. With it off the temps rose to 96 and ran from the thermostate temps and everything settled and passed.
I’ve double checked the map, the thermostate and my temp gauge and they are all working/reading ok, I ran the car upto temp whilst stationary and the
fan came on at 96 and off at 90, which matches the gauge and ecu.
When out driving the temp gauge doesn’t get to 80 degrees unless I’m in traffic then the fan kicks in as normal at 96.
I have a coolex 50mm ally rad (their 7 one), with a blow through 9” fan. My 2.0 blacktop on TB’s and emerald is plumbed as suggested by Tiger. The
bypass is blanked off, as is the heater. There’s then 2 holes drilled into the thermostate itself to allow flow that would usually be through the
bypass.
why can’t i get the temps up? shouldn’t a zetec be running at 90+ degrees
cheers in advance for any help
Hi there. Ideally I would suggest re-instating the bypass flow and using an undrilled thermostat. Other than that you could investigate some sort of
radiator blind, adjustable if possible.
My car used to be plumbed in a similar way to yours. Bypass etc blocked off; drilled thermostat. The problem I got was that the dynamic pressure
created by the pump caused the top hose to blow off at high revs on more than one occasion. You could feel the hose expanding as you revved the
engine. I fitted an external thermostat which had it's own bypass and re-instated the redundant heater flow.
A similar external 'stat could solve your problem.
It's because the by-pass circulates water back to the block uncooled. Your 2 holes in the 'stat allow it to circulate through the rad'; Effectively you've got a stat that's stuck slightly open. Even 2 tiny holes will cause enough cooling to be noticable.
"When out driving the temp gauge doesn’t get to 80 degrees unless I’m in traffic then the fan kicks in as normal at 96. "
I am no expert, but to me this seems to be bang on, and your cooling correct, and if it was my car, feel that there was not a problem
why do you think your under cooling (a very rare thing with our style of cars ) ?
steve
If he is running a normal Zetec 'stat, 88 or 92 degree IIRC, then the coolant should warm up to that temperature fairly readily. It would seem that the flow through the holes in the 'stat is seemingly enough to overcool the water and keep it substantially below the opening temp. How big are the holes OP?
As said in a few answers - drilling holes in stats is going to cause over-cooling at low loads. This is why bypasses are designed in by the OEM, so you don't need such a kludge.
when were your figures taken ? in August or two days ago ?
As the ambient temperature is considerably different
I doubt I could even get the fan to come on in this temp, even leaving it running for an hour stationary
are you on a standard or aftermarket ecu?
if aftermarket can you adjust the cold start temp lower so it isnt chucking in as much fuel
3mm holes and Emerald K3 ecu
There's your problem.
I would cover some of the radiator the old fashion way, tape some cardboard over the radiator in strips either side and keep adding till temps are
where you would like them.
When you have the temps in the right place you can fabricate some ally sheet which is easily removable for hotter days.
I do think however it’s a flow/thermostat proble and an easy solution is to replace the thermostat, see what one with no holes does then start with a
smaller single hole and slowly build if required
I'm happy to be proved wrong but would be surprised if it is due to the two 3mm holes, thats smaller than the diameter of a straw.
First step is to get a new thermostat at the required temperature and check it opens correctly, an IR thermometer is recommended for accuracy. If you
need to have a hole, start with one 1 or 2 mm, should be enough for bleeding.
Why would over cooling bother you? Over heating kills engines quickly not over cooling. Now I know hundreds of people will immediately shout at me
and state 'over cooling a engine will reduce its life expectancy and promote accelerated wear' or 'engines are designed to run at
certain temps etc'. But in reality what does it matter? Most engines these are designed with 250000km but thats in a tin top. Are you really
bothered if you 'possibly' reduce life expectancy?
If I get 20K out of my V8 I'll be happy. I did build it out of bits though.
2*3mm diam is about enough area to flow ~200cc/s at full choked flow. I'm guessing the pressure from the stat would be lower, but you're
still looking at hundreds of watts of cooling capacity given the specific heat capacity of water.
Overcooling potential problems:
over-fueling
bore wash (due to overfueling)
incorrect timing
drivability problems (due to fuel vaporization being poor)
increase clearances = decreased life and more rattle
Why would you not just change the stat to check it, stick the bypass tube in and know it's right?
I tried without a bypass with no success, e.g. no stat, 3mm hole in stat. Even the tiniest hole will flow a significant amount of coolant, enough to
overcool. In the end I did it properly utilisting the bypass exit in the stat housing. Has been faultless since and is self bleeding.
Agree 3mm holes x 2 is the problem and I had the similar though perhaps 2 x 2mm. Change the stat and I think I put 1 x 2mm hole and it now worked fine.
quote:
Originally posted by coyoteboy
2*3mm diam is about enough area to flow ~200cc/s at full choked flow.
I think your thermostat isn't fully closing.
Like coyoteboy says "Why would you not just change the stat to check it, stick the bypass tube in and know it's right?"
quote:
Originally posted by 02GF74
quote:
Originally posted by coyoteboy
2*3mm diam is about enough area to flow ~200cc/s at full choked flow.
I am sceptical - where did you get that figure? It does not feel right.
If I get time, I will try this with a short length of garden hose (mains pressure I would expect to be more than that produced by the water pump but I could be well wrong here). I find it hard to believe I will get 2.6 gallons or 12 litres in a minute from two 3 mm holes.
Well it’s all gone tits up this morning, been in the garage to start swapping over to use the by pass. Started the car to pull it outside to sort out
the garage, gave it a little blip and woosh, I’ve now got coolant blowing out from behind the timing cover. I’ve pulled the belt, idlers and
alternator off and removed the cover and theres nothing obvious that i can see.
There's no water in the oil, no sludge in the cap and when the engine stopped the coolant stopped. Is there a plug/ blank behind the timing belt
anywhere, it seems to be coming from the the middle to left hand side on the front of the engine as you look at the crank. no sign of any other leaks
anywhere and theres still coolant in the bottle.
Water pump bleed hole?
Beg ,borrow or steal a cooling system pressure tester but make sure it has an adaptor to fit your rad cap.Pity your not closer, you could borrow mine
quote]Originally posted by SPYDER
Water pump bleed hole?