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Author: Subject: Robin hood zetec cooling
kylerichmond

posted on 30/12/11 at 12:05 PM Reply With Quote
Robin hood zetec cooling

I have a polo radiator fitted to my robinhood however when driving it performs ok, when in the summer months and driving hard it struggles a little, i have noticed that when i stop the engine sometimes it will boil over, even thought the guage in the car is within temperature, if it rains the car stays nice and cool.

Yes the car is plumbed up correctly!

I have put 2 extra vents in the side of the car to help let warm air escape

I have noticed that above the rad i have a fairly large gap between the chassis and nosecose, where the bonnet would sit, would i be right in saying this would massively reduce cooling due the the air coming in from the nose cone bypassing the radiator and going over the top? if i blocked this would it help?

Why doe it only boil when i stop?

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whitestu

posted on 30/12/11 at 12:42 PM Reply With Quote
Sounds like there is a problem with plumbing or a thermostat or possibly head gasket issue.

Does it keep cool when the car is stationary?

I have the same setup in my MK and it easily keeps cool. Driving hard doesn't increase the temp at all and when ticking over it goes up then comes down when the fan comes on.

Stu

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mark chandler

posted on 30/12/11 at 12:43 PM Reply With Quote
Ducting air to radiators makes a huge difference, all car manufacturers do this so make up some shields.

However I suspect this is not your problem, boiling over when stopped indicates an air lock, have you a small 1/4" bore pipe for air to bubble steam off the head ?

This would typically go back to the header tank and plumb to the highest point of the engine, ie where bubbles collect, without the water will boil and push liquid out the header tank or create another air lock.



Regards Mark

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kylerichmond

posted on 30/12/11 at 01:25 PM Reply With Quote
If i leave the car ticking over it will stand all day with no problems, the problem is if i driving it quite hard and stop, switch the engine off it will boil over, on the move its fine.
Another point to mention is that i thought it could be air, mt bottle is on the bulkhead so high as i can get it, my radiator has not got an outlet so i can tee it into the bottle and top of the thermostat housing, but the outlet is in the cast therefore i may be able to drill it to add one, would this help?

I am confident the head gasket is fine

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kylerichmond

posted on 30/12/11 at 01:27 PM Reply With Quote
have you a small 1/4" bore pipe for air to bubble steam off the head ?

Where would this be then? i suspect no

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kylerichmond

posted on 30/12/11 at 02:17 PM Reply With Quote
Just to add i am running a rover 25 expansion bottle, would the problem have anything to do with the cap rating?
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snapper

posted on 30/12/11 at 02:58 PM Reply With Quote
Ducting or a simple bulkhead will help a lot
Check this plumbing diagram out







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kylerichmond

posted on 30/12/11 at 03:00 PM Reply With Quote
Thanks

My cooling system uses and expasion bottle so is a little different to this setup

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designer

posted on 30/12/11 at 03:19 PM Reply With Quote
Have you a temp controlled electric fan wired separate from the ignition?

I have and it works.

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Paul Turner

posted on 30/12/11 at 05:02 PM Reply With Quote
If you go to the following link and scroll down to a post by Lewis you will find the picture he kindly posted for me.

http://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=161780

Mine has been plumbed like this for 10 years now with no problems at all. It reproduces exactly how the Mondeo and Focus are plumbed plus its exactly how Mr Dunnell does it, don't like the bloke but he knows a thing or two about Zetec's.

The heater outlet on the drivers side of the stat housing is blocked off since I don't have a heater. Don't use that outlet for the bypass pipe, it will not work, the one under the top hose as shown on my diagram is the bypass outlet. If you have a heater it needs to be connected between a tee in the bypass pipe and the pipe that I have blocked off.

You need a bleed pipe from the top of the stat housing, thats why Ford put the outlet there.

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Greenie

posted on 30/12/11 at 07:24 PM Reply With Quote
I had a very similar issue and used the diagram in the link and replumbed the entire system, it seems to have worked for me, I suspected that my system was generating air, this seems to have cured it..........
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kylerichmond

posted on 31/12/11 at 12:19 PM Reply With Quote
1.)I going to start from scratch, firstly im going to move the rad from behind the cross member even thought its got some holes for airflow and move it into the nose cone where i figure more air will be forced through.

2.)Secondly im putting the fan on the other side of the rad therefore it will now blow through rather than sucking

3.) Im increasing the 28mm copper to 32mm and 15mm copper to 19mm pipe

Do you think this will help?

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Paul Turner

posted on 31/12/11 at 04:42 PM Reply With Quote
My rad's in the nosecone, always has been, best place for it, no restrictions to air flow.

My fan sucks but it does not really matter as long its the correct fan for the location, once you are on the move the fan should never operate anyway. Car looks better with fan behind rad IMHO plus my ancient Escort (or whatever) fan motor would stick out of the grill)

Think my main pipes are 32mm, same as the thermostat outlet, no need for any bigger. The bypass is 15mm copper, no need for anything any bigger since it only really has a flow during warmup, after that its the main pipes that carry the water to the radiator.

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