Ke70 Radiator Replacement

[hamisbrown]

hey guys, its coming up to summer and I'm looking to upgrade my radiator. i have a stock one with a thermo fan.

 

last summer i had alot of trouble with over heating going up winding hills, sitting in traffic and even going 100km/h down the highway on a 30 degree day.

 

i've had a look around and there are 3 core alloy radiators on ebay for $300 posted. was wondering if they would be a good op. i also have a spare stock radiator, would be it be just as benefical to get a new core put in that one?

 

any info would help

 

i am currently building a worked 5k that will hopefully be put in soon so it will need to be able to handle that aswell.

 

cheers, hamish

Edited November 17, 2014 by hamisbrown

[rian]

Alloy radiators work well, and ebay ones seem to be of reasonable quality, but even a stock radiator should keep a worked 5K cool.

Before you buy a new radiator you should first try checking the thermostat, checking the propeller on the water pump, and flushing your current radiator/ inspecting the fins. If the fins crumble in your hands just chuck it and buy a new one or fit your spare radiator if you want to save money.

Edited November 17, 2014 by rian

[Super Jamie]

Do you have a shroud on your radiator? As in a big flat piece of metal which covers the radiator except for a round hole where the fan goes?

 

If not, do this first. A thermofan without a shroud is not even using half the radiator area.

 

Don't put bolts through the radiator fins, the radiators have bolt holes on the side. Bolt the shroud to the radiator, and the fan to the shroud.

 

This is what a good custom radiator shroud looks like: http://www.maxrevs.co.uk/cars/bmw/carimages/2008/3/10_1200457039_thumb.jpg

[altezzaclub]

The best way to go 100kph on a hot day is with no fan at all, so there are other problems in your cooling system.

 

The fan and shroud only get in the way of airflow and make the radiator less efficient at speed. However when sitting in traffic or crawling along they are only way to get the radiator cooled, so they are a vital compromise.

 

KE70s have a conical plastic shroud as stock on the slantys, you can probably find one of those. I think they came out with the silicon-clutch fans (the thermo-fan) so you should be able to find one. Otherwise make one up like Jamie said, but make it conical to come back to the fan blades.

 

My '83 slanty had the thermo fan and the shroud & my '83 flat-front had a solid fan and no shroud. I fitted an electric fan to the slanty and moved its thermofan to the flat-front as that had a worn waterpump when I bought it.

 

The slanty is modded with cam and everything , yet never runs hot and the fan only comes on after sitting and idling for 5minutes or more. The thermo-switch I bought is a 90deg one.

 

The dead stock flatfront runs warm all the time and you can see the temp go up in the hills. The difference is that although I've had both heads off, I took the motor out of the slanty and cleaned all the rust and scale out of the water-jackets in the block. It was bridging the cylinders in places and I was surprised how much was in there.

 

So, as Rian said, you need to make sure the rest of the cooling system is as good as new before buying a new rad and finding it makes no difference. Along with checking the pump and the t'stat, try some radiator flush stuff and hose the block out with the pump and t'stat housing off. That's the best compromise I can think of rather than pulling out the motor and cleaning the water jackets out properly.

[ke70dave]

The standard ke70 radiator is a full copper unit which id guess would be on par with a similar sized full aftermarket aluminium (pending thickness)

 

So if you actually need a new radiator (ie check rest of system first) i would just get a new standard radiator.