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

What's your engine and any pictures of your current setup ?

It's an ST170 (zetec) engine so nothing clever, it's plumbed up as per the diagram below:

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 .

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.

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?

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.

quote:

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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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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 .

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?

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!

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

quote:

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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.

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Ok here are some pictures for observation:

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

It wouldn't be a bad idea to fit a bleed valve in the top hose.

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

quote:

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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

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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.

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

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

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.

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.

quote:

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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.

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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

quote:

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Originally posted by CosKev3
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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