Radiator flow rate?

[Ross]

I've spent some time this week pulling my RS2 apart to get to the bottom of my overheating.

Tonight I confirmed the thermostat is not faulty and the water pump is not damaged, so that's all working as it should. I then plugged the radiator so i could pump water into the top and measure flow through the bottom. I don't expect it to flow i huge amount, but even with some pressure I couldn't get it higher than about 1l per minute. Letting water through from a pipie held about 18" above the rad it was about 0.5l per minute.

To me that sounds too slow, but then I have no idea what the flow rate of the water pump is or what it should be capable of.. it may be that is normal and adequate...

Any experience here? I'm tempted just to buy a new one as a spare (current is 5yrs old) and test that against it...

Hoping it's a problem as next it's head off

[Kieron20V]

That doesn't sound right to me.
Whenever I've flushed rads on any car its poured out the bottom hose st the same rate its gone in the top. Sounds like its full of crap, have you tried giving it some light jet washing from both ends see if you can clear it out? Has it had rad weld or something similar in at some point?

Sent from my HTC One X+ using Tapatalk 2

[driftin jo]

You have found you problem, you rad is fooked.

[A80Avant]

Has happened to me after my first rebuild. Engine sat for 3-4 weeks with old coolant and we go it running and engine overheated. Replaced the rad only to find out that it was full of pink crap that bloked 2/3 of it

[Ross]

Thanks for the quick responses guys.

It's hard to find info on radiator flow rates (with google), but I found a couple of results... I'm seeing figures of 10-15l per minute at idle from the water pump and 60-100l per minute at high revs, and measured flow rates through the radiator for 30-50l per minute as 'normal' on some Lotus engine.

Rad must be blocked, I'll give it some treatment with a pressure washer and if that's not forth coming get a new one. I must admit I'm a bit relieved, I was starting to plan when to lift the head... fingers crossed there's been no damage from the coolant loss.

[DJones]

Thanks for the quick responses guys.

It's hard to find info on radiator flow rates (with google), but I found a couple of results... I'm seeing figures of 10-15l per minute at idle from the water pump and 60-100l per minute at high revs, and measured flow rates through the radiator for 30-50l per minute as 'normal' on some Lotus engine.

Rad must be blocked, I'll give it some treatment with a pressure washer and if that's not forth coming get a new one. I must admit I'm a bit relieved, I was starting to plan when to lift the head... fingers crossed there's been no damage from the coolant loss.

Ross,

Certain types of antifreeze don't mix the blue with the pink for example, it turns to jelly as A80Avant describes, I have heard that in some instances even certain types of the pink wont mix. Can't remember the names of the chemicals but have witnessed it first hand.

I would get a new rad or the old one rebuilt.

Darren.

[Ross]

That's a good point. I recall the duff radiator cap was pretty gunked up, probably why it wasn't holding pressure, I suspect at some point it's had a mix in there.

I thought about replacing the radiator when I refitted the engine but it was replaced only 2yrs before I bought the car and hadn't had any issues.

Anyone bought a Behr recently.. I found one on Amazon for £165 but it says 1-2 months for delivery

[audinut]

i manged to get one from euro's for about 65 quid but it has no port for the aux rad so i deleted it , if youd like i can check to see if i can get another?

[A80Avant]

I bought my latest one from ebay. Usually there is a shop that has them straight away

[Ross]

I have got rid of the aux rad so not fussed if there's no where to attach it!

If ECP stock it I'd be very interested, can get it quickly too, is it Behr though? Seems cheap and i dont want a nissens that i'll be changing in 2 years time. If you have a part no or can confirm stock that would be great.

I'll check ebay too...

[5cylinderman]

An Ex VAG mechanic once told me that OE G12 coolant has a type of "self sealing" property when in contact with air. I have seen it loads of times around the coolant connections on tdi oil coolers over the years. He advised flushing my cooling system with water before long term work to prevent pink furry stuff building up in my rad and heater matrix.
Has anyone else seen this?

[johne]

I have got rid of the aux rad so not fussed if there's no where to attach it!

If ECP stock it I'd be very interested, can get it quickly too, is it Behr though? Seems cheap and i dont want a nissens that i'll be changing in 2 years time. If you have a part no or can confirm stock that would be great.

I'll check ebay too...

I've got the ECP one and it's certainly not Behr! It's a Chinese copy built in the style of a heater matrix, i.e. aluminium tubes and fins with plastic end tanks and the tubes sealed to the end tanks with rubber seals.

It fitted alright but one of the mounts was out of alignment so it sits slightly skew in the car. It has no take off for the aux rad which was what I wanted.

I don't believe it has the cooling capacity of the Behr but having refitted my undertray and oil cooler the engine doesn't overheat even without the aux rad and managed 270HP on the recent rolling road day @27 degrees with no overheating.

It's approx. 18 months old and no problems so far.

John

[SteveH]

A lot of the new rads have thinner cores so watch out for that. I'd go with the Behr unit at just over £140 delivered. Fit and forget!