Daf
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| posted on 17/12/16 at 07:56 PM |
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Radiator size and position
So I failed my IVA for the second time yesterday - passed on everything excluding the emissions. It wasn't that the emissions were out but after
7 or 8 minutes at 2500-3000 RPM it boiled over, to be fair Mr IVA was very helpful, even got a desk fan and put it in front of the car to try
again!
Anyway I was thinking of fitting a bigger rad and better quality fan, I have plenty of spare height to fit a bigger radiator in but this would put the
top of the rad at the same height as the header tank. Can anyone give me some guidelines with regards to height of header tank, engine, radiator and
what I can get away with and what works best?
I'm currently using a standard polo rad but I'm thinking of swapping to one of these if the height thing is in issue - any thoughts?
VW POLO DERIVED WESTFIELD & OTHER KIT CAR, 55MM ALUMINIUM RACE RADIATOR UK MADE.
Thanks
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Toprivetguns
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| posted on 17/12/16 at 08:04 PM |
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What's your engine and any pictures of your current setup ?
Only drive as fast as your angel can fly... !
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Daf
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| posted on 17/12/16 at 08:20 PM |
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It's an ST170 (zetec) engine so nothing clever, it's plumbed up as per the diagram below:
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ian locostzx9rc2
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| posted on 17/12/16 at 09:18 PM |
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Worth getting one of those rads fitted one to my striker as on trackdays temps where marginal made a huge difference reduced temps by 10 deg very good
quality and good customer service .
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benchmark51
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| posted on 17/12/16 at 09:29 PM |
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I used this one;
3ROW ALUMINUM RADIATOR For 1992-2000 Honda CIVIC D15 D16 EK EG / INTEGRA DB DC
Really pleased with it and delivery was mega quick. Loads of mounting points and a proper drain bung.
I fitted the fan on the engine side, sucking air through, more efficient that way.
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Daf
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| posted on 17/12/16 at 10:16 PM |
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Thanks all, new rad ordered.
I have my rad top hose to stat housing running over the top of the manifold so it's quite high compared to the expansion tank. I have a bleed
fitted but what are peoples thoughts on it?
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02GF74
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| posted on 17/12/16 at 11:11 PM |
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Did the fan turn on? At what temp does it turn on/off? How large is the fan? Is it mounted before or aftet radiator and which way is it
pushing/pulling air.
Is the thermostat opening?
Is the water pump working?
Are you certain there not an airlock in the cooling system?
Is engine timing correct?
Id be concerned that it overheated in these temperatures at very little load its not exactly what id call sweltering.
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Daf
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| posted on 17/12/16 at 11:28 PM |
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quote:
Originally posted by 02GF74
Did the fan turn on? At what temp does it turn on/off? How large is the fan? Is it mounted before or aftet radiator and which way is it
pushing/pulling air.
Fan is before radiator and only a cheap eBay one, having read peoples reviews it's going in the bin!
Is the thermostat opening?
- Should be - it is brand new, l will do the kettle trick to check it though
Is the water pump working?
- Yep
Are you certain there not an airlock in the cooling system?
- No!
Is engine timing correct?
- Should be, it's using standard parts and a map supplied by emerald
Id be concerned that it overheated in these temperatures at very little load its not exactly what id call sweltering.
Me too, something is certainly not right
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ian locostzx9rc2
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| posted on 18/12/16 at 09:28 AM |
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I agree with all the comments but the biggest problem with kitcars is coolant capacity it's amazing what an extra litre or more coolant can do
you will more than likely need a bigger fan aswell and may need to look at getting the hot air out of the engine bay quicker aswell in the future once
it's on the road .
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rusty nuts
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| posted on 18/12/16 at 10:48 AM |
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It also sounds like you have a large air gap at the top of the rad which may have an effect on airflow through the rad ? Was it overheating with the
bonnet on or off? As said allowing heat build up to escape helps . Have you driven the car, did it overheat? Is the fan operating in the correct
directions? Was the engine a known good runner with no overheating problems previously to fitting in the kit car? I think my first port of call would
be a sniff test , any hydrocarbons escaping from the header tank indicate a failed head gasket /cracked head. Failing a sniff test a block test would
show up the same . As said fan switch location and operating temperatures may also have a great effect on temperature. Is the water pump rotating in
the correct direction? I believe an idler pulley is required with a Zetec engine?
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Daf
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| posted on 18/12/16 at 11:06 AM |
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Fan is switched off the ECU and gets its signal from the standard zetec temp sensor in the thermostat housing. The engine is a known good one so
I'm 99% it's not a HG problem.
From what I've been reading I think my fan set up (unbranded one on the front of the rad) leaves a lot to be desired. I'm also suspicious
of the top hose to thermostat housing pipe being so high and trapping air.
The water pump set up is a retroford kit - I'll get a picture up so the collective can confirm it's running the right way.
Sadly I'm not able to drive it, I have nowhere to try it!
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rusty nuts
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| posted on 18/12/16 at 11:12 AM |
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A bit of a bodge but it works is Water Wetter from Red Line , it will lower the coolant temperature by up to 20 degrees
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02GF74
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| posted on 18/12/16 at 12:24 PM |
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quote:
Originally posted by Daf
From what I've been reading I think my fan set up (unbranded one on the front of the rad) leaves a lot to be desired. I'm also suspicious
of the top hose to thermostat housing pipe being so high and trapping air.
The water pump set up is a retroford kit - I'll get a picture up so the collective can confirm it's running the right way.
ok, so let's see photo of the fan set up. What diameter and how far from front of radiator is it?
as i'm sure you know, the flow of water should be set up so that hot water goes into the top of the radiator.
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Daf
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| posted on 18/12/16 at 01:47 PM |
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Ok here are some pictures for observation:
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Oddified
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| posted on 18/12/16 at 04:09 PM |
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Those cheap fans are rubbish, been there and got the T shirt with my car.
Swap it for a proper Spal or Pacet etc and there's a huge difference in air flow even with the same size. Also do some googling, the proper
makes do several versions of the same diameters with different flow rates (larger motors fitted). They're more expensive for a reason.. 
Overheating at this time of year though, there may well be other contributing factors that also need looking at.
Ian
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rusty nuts
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| posted on 18/12/16 at 04:58 PM |
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It wouldn't be a bad idea to fit a bleed valve in the top hose.
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obfripper
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| posted on 18/12/16 at 08:24 PM |
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The fan as installed is a pull fan, you may have reversed the motor direction to make it push but the efficiency will be greatly reduced.
If you've enough room, moving it behind the rad and wiring it to spin anti-clockwise will make it far more efficient in operation. If this is
not possible, the blade may be reversible, reversing the blade and spinning clockwise will maximise the airflow in a push setup, but will not be as
efficient as a pull setup.
The bleed line from the engine and radiator should be higher than the rest of the system to prevent airlocking, there should be a reasonable stream
returning through this line all the time with sporadic air bubbles passing through.
I would not blank off the bleed from the radiator as it will result in airlocking, tee'ing it like your first pic but running in a straight line
from the rad bleed to header tank above the level of the main pipe should draw off any air as best as possible.
Have you got any kind of pressure tester to hook into the system? (a cheap option is a footpump hooked into the bleed line, you will get a hiss when
you reach the cap release pressure)
If the pressure cap on the header tank is not working correctly the car will boil before the cooling fan even cuts in.
There are also multiple pressure caps for the rover type header tank, and a patterned one is likely to hold no pressure at all (i've nearly had
a shower while mot'ing several rovers due to patterned caps that don't work), they look like original but that's where the
similarities end.
PCD000040 is 1.5 bar and will fit your header tank, and is pretty close to a standard zetec cap(1.45 bar).
The rest of your cooling system looks ok, you have the correct pump setup. The thermostat to radiator main pipe could do with being a bit lower but
there is not much option with the location of the exhaust manifold, plenty of others have the same arrangement without problems.
Dave
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Daf
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| posted on 18/12/16 at 09:09 PM |
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quote:
Originally posted by obfripper
The fan as installed is a pull fan, you may have reversed the motor direction to make it push but the efficiency will be greatly reduced.
If you've enough room, moving it behind the rad and wiring it to spin anti-clockwise will make it far more efficient in operation. If this is
not possible, the blade may be reversible, reversing the blade and spinning clockwise will maximise the airflow in a push setup, but will not be as
efficient as a pull setup.
The bleed line from the engine and radiator should be higher than the rest of the system to prevent airlocking, there should be a reasonable stream
returning through this line all the time with sporadic air bubbles passing through.
I would not blank off the bleed from the radiator as it will result in airlocking, tee'ing it like your first pic but running in a straight line
from the rad bleed to header tank above the level of the main pipe should draw off any air as best as possible.
Have you got any kind of pressure tester to hook into the system? (a cheap option is a footpump hooked into the bleed line, you will get a hiss when
you reach the cap release pressure)
If the pressure cap on the header tank is not working correctly the car will boil before the cooling fan even cuts in.
There are also multiple pressure caps for the rover type header tank, and a patterned one is likely to hold no pressure at all (i've nearly had
a shower while mot'ing several rovers due to patterned caps that don't work), they look like original but that's where the
similarities end.
PCD000040 is 1.5 bar and will fit your header tank, and is pretty close to a standard zetec cap(1.45 bar).
The rest of your cooling system looks ok, you have the correct pump setup. The thermostat to radiator main pipe could do with being a bit lower but
there is not much option with the location of the exhaust manifold, plenty of others have the same arrangement without problems.
Dave
Hi Dave, thanks for your input
How do you know the fan is a pull fan? It was sold as a "wire it up whichever way you want" off eBay, I'll be fitting a quality one
anyway but just curious how you identify a push/pull?
I'll re-plumb the bleed lines above the main pipe - obvious when you point it out that they should be higher, I'll also re-attach the
engine bleed.
I could fit the main pipe under the manifold it would have a downhill and uphill in it at each end but if the bleeds are above it I assume this
wouldn't be an issue?
New expansion cap just ordered from Rimmer Bros as per your recommendation!
With regards to radiator is it simply a case of bigger is better? I'm planning to replace it and have 3 options on thickness 42/55/70mm - is it
simply a case of 70mm is better or am I missing a fundamental point?
Thanks again for the feedback people - I'm running out of time for my 6 month IVA retest!!
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02GF74
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| posted on 18/12/16 at 09:31 PM |
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Noone has mentioned fitting acowl for the radiator fan. What this does is force air through a much larger surface area. You have spave for a larger
fan.
If you can get fan us cowl from original or make one, just a shallow pyramid shape, bit of ali sheet held togetber e.g. rivets and fit behind if
theres room or in front.
Im pretty sure ive read on here polo radiator bei.g used on v8 s so not entirely convinced size of radiator is at fault.
If you remove thermistat, does it overheat, may be enough to get thru iva then have time to sort it.
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obfripper
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| posted on 18/12/16 at 11:56 PM |
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The concave face (shortest cross section) of the blade should face in the direction you want to move the air (towards the rear), so the aerofoil
section is working correctly. Taking a second look at your pics the concave face is not as obvious as i first thought, but with correct direction of
rotation the blunt edge of the blade should be leading and the thin (tapered) edge should be trailing.
If your searching for a spal fan they usually state pull(suction) or push(blow) in the description, and afaik they do not do a universal fan that will
do either function.
Ideally the main pipe should be straight/level between the thermostat outlet and the radiator inlet. I don't think you have the option to do
this, running underneath may have some beneficial effects as there will be less heat soak on the pipe. However there are plenty of people running
zetec's with the coolant pipe above the manifold with no cooling issues.
The radiator you have should be sufficient for your engine as standard, an uprated radiator will give you extra capacity if you decide to fit cams
etc.
I'm fairly certain that your main issue is insufficient cooling system pressure, the other things are just teething problems.
Dave
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Daf
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| posted on 19/12/16 at 10:13 AM |
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Right I'll get some changes made this week and some tests done over the weekend (perhaps not Sunday mind!) I'll post some pictures of the
changes and we'll see what difference they make.
Thanks people 
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Daf
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| posted on 21/12/16 at 03:53 PM |
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Well looks like I found the culprit, 10 minutes on the hob and no movement whatsoever from the thermostat. Annoyingly it was a new one when I fitted
the engine.
Anyway a new radiator and a spal fan are sat in my lounge waiting to be fitted along with an expansion tank cap in the post somewhere.
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02GF74
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| posted on 21/12/16 at 05:34 PM |
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Well, if the thermostat is not opening, you have the cause. Buy new one, test it in pot of boiling water and fit. It is beneficial to drill a 3 mm
hole to allow a bit of flow and help prevent airlocks.
That should be it. I personally do not like fans mounted through the radiator so if your new fan fits to surround, then fit that.
I reckon you can return the new radiator for a refund, thats optional.
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Daf
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| posted on 21/12/16 at 05:50 PM |
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quote:
Originally posted by 02GF74
Well, if the thermostat is not opening, you have the cause. Buy new one, test it in pot of boiling water and fit. It is beneficial to drill a 3 mm
hole to allow a bit of flow and help prevent airlocks.
That should be it. I personally do not like fans mounted through the radiator so if your new fan fits to surround, then fit that.
I reckon you can return the new radiator for a refund, thats optional.
To be honest I think I'll keep the new rad - gives me scope for future development on the engine without having to worry about heat.
It's just rather frustrating that a £10 thermostat has turned into a £300 IVA retest!
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CosKev3
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| posted on 21/12/16 at 05:52 PM |
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I would T the bleed pipe from the top of rad into the small pipe going to top of header tank too
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