Radiator / Cooling Pack Distortion - The Unofficial BMW M5 Messageboard (m5board.com)

davidoli · 13th July 2008, 12:18

Recently removed from Hertfordshire1's M5 , notice the distortion of the rad at the top .

I also had this occur on my first E34 M5 , same sort of distortion in the same area .

We decided it best to renew the offending item prior to our Ring trip :

Have any other members experienced this ?

Any ideas as to the cause ?

Ross D · 13th July 2008, 17:50

Hi
I have seen an e36 radiator go like this.
It looked alot worse than that radiator as if it was sagging down at the bottom.
I'm not sure what caused it but I fitted a new cap aswell just incase it wasnt releasing the pressure properly.
after fitting the new rad and cap the car was fine.

raymondw · 13th July 2008, 19:23

David,

I have seen such damage on my former Audi S2 Avant and it collapsed soon after.

HD91 · 13th July 2008, 19:47

Yep, it recognize that. My former 3.6 from 1989 had that failure and eventually started to leak.
No idea why. Maybe it was overheated once in the past and that caused it?

davidoli · 14th July 2008, 09:53

Thanks for the replies guys .

On the radiators in question , were they all relatively old ?

Would this be something that gets gradually worse until complete failure or would the rad be fine one day and totally warped the next ?

The reason that I ask is that I have been advised by a senior esteemed member who has experienced this recently , that the symptom is purely a result of old age .

HD91 · 14th July 2008, 11:11

Yes, my radiator was the one fitted at the factory = it was 13 years old at the time.

The leak came graually. One day I could smell some coolant fluid and at a later point there were two holes at the upper section of the radiator.

raymondw · 14th July 2008, 11:13

Yes, it was the old rad (11 years old when I sold the S2 in 2005). The rad in my E34S is 18years old and doesn't have such damage though, but that one has always been run on 100% glycol (nitrate free) that has been replaced everey 4yrs since I have owned it. I suspect it has to do with adding a mixture of water and antifreeze. The minerals in the (not demineralized) water will react with the pipework reducing the flow capacity and increasing the pressure in the rad.

DrSakke · 14th July 2008, 11:51

Quote:

Originally Posted by raymondw

Yes, it was the old rad (11 years old when I sold the S2 in 2005). The rad in my E34S is 18years old and doesn't have such damage though, but that one has always been run on 100% glycol (nitrate free) that has been replaced everey 4yrs since I have owned it. I suspect it has to do with adding a mixture of water and antifreeze. The minerals in the (not demineralized) water will react with the pipework reducing the flow capacity and increasing the pressure in the rad.

I thought it was NOT recommended to run on pure glycol(antifreeze) the recommended mixture should be 50/50.
I run my M5 with this, just changed every 3-4 years. Original rad. changed as part of preventive maintenance summer 2007, It still looked like new externally.
I would tip road salt+internal corrosion due to neglected cooland changes previously in the cars life and time of course.
Using tap water in the coolant could be an issue, It was used in my car without any detrimental effect but after the new rad was put in, distilled water was used.

Sakke

FinalEditionE34M5 · 14th July 2008, 12:34

My Rad was changed in January of this year - the car was 12.5 years old at that point - and on the factory item.

It too, was bowed at the top - and leaking out through the central core in places, too.....

Replaced with a BMW item at outrageous expense...

farrell · 14th July 2008, 13:18

Radiators can just fail as the cores become tired from years of use.
They get hit by stones & debris which can weaken them also.

It can also be helped to fail by years of neglect to the cooling system
where regular coolant changes using distilled water & coolant are not adhered to.
I have seen numerous radiators warp when the cooling system aspirator hoses
have blocked with sediment = pressure lock.
This causes over heating & a massive difference in pressure from cold side of
engine to hot.
The weak point for pressure spikes will be the radiator core.

Neither aspirator hose on top or bottom hose side of engine bleeding into the de-gas tank.
This has been typical of many cars seen.
Sometimes the damage is already done to the cooling parts.