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stevecvo

Radiator repair

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When I opened the bonnet of my 525d today to check fluids I noticed a small area of dried coolant staining at the front left hand side of the engine bay. I eventually traced a small split in the plastic header tank of the radiator. I drained the radiator, degreased the area and roughed it up with sandpaper before applying some expoxy resin  to effect a temporary repair - which seems to have cured the leak . I have ordered a new radiator as the original is 20 years old but it set me wondering whether with a newer rad it would have been possible to do a long term repair to the plastic. Has anyone any experience of doing this?

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1 hour ago, stevecvo said:

When I opened the bonnet of my 525d today to check fluids I noticed a small area of dried coolant staining at the front left hand side of the engine bay. I eventually traced a small split in the plastic header tank of the radiator. I drained the radiator, degreased the area and roughed it up with sandpaper before applying some expoxy resin  to effect a temporary repair - which seems to have cured the leak . I have ordered a new radiator as the original is 20 years old but it set me wondering whether with a newer rad it would have been possible to do a long term repair to the plastic. Has anyone any experience of doing this?

No, because pressure is changing and everything glued on top will eventually separate from surface and leak will return. So no point to repair plastic cooling system parts.

Actually 525d has separate expansion tank from radiator. So you replace either expansion tank or radiator. Petrol engines have expansion tank attached to radiator as far as I know.

I had a split in my 525d expansion tank, replaced only expansion tank, radiator still going faultless.

By the way there's coolant bleeding screw in plastic pipe near power steering pump. If that's been overtightened, pipe can split. Coolant will drip on drive belt and splash everywhere around front of engine bay. Quite hard to understand what's leaking, because bleeding screw is under front engine cover. 

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5 hours ago, Ray112 said:

No, because pressure is changing and everything glued on top will eventually separate from surface and leak will return. So no point to repair plastic cooling system parts.

Actually 525d has separate expansion tank from radiator. So you replace either expansion tank or radiator. Petrol engines have expansion tank attached to radiator as far as I know.

I had a split in my 525d expansion tank, replaced only expansion tank, radiator still going faultless.

By the way there's coolant bleeding screw in plastic pipe near power steering pump. If that's been overtightened, pipe can split. Coolant will drip on drive belt and splash everywhere around front of engine bay. Quite hard to understand what's leaking, because bleeding screw is under front engine cover. 

 

this.

 

However, I've welded plastic tanks in order to keep a car operative until replacement part arrived, and while it's technically a momentarily repair (just to "limp" its way until you freshen up what needs replacement) I know of a friend of mine who was tight on money and asked if he could have my welded up radiator and he's still using it 5 years after I discarded it. I did excatly the same process I showed on the clutch pedal plastic weld.

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I replaced the expansion tank a few years ago because it developed a leak at the seam below the top and I have experience of a leak from the EGR thermostat bleed screw. In the old days I repaired radiators with solder and I simply wondered with all the magic that seems possible on the repair of plastic items these days there was any way of repairing a hairline split in the radiator plastic tank.

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43 minutes ago, stevecvo said:

I replaced the expansion tank a few years ago because it developed a leak at the seam below the top and I have experience of a leak from the EGR thermostat bleed screw. In the old days I repaired radiators with solder and I simply wondered with all the magic that seems possible on the repair of plastic items these days there was any way of repairing a hairline split in the radiator plastic tank.

I have repaired old radiators with solder as well, and it usually was a good success to be fair, but with plastic I wouldn't trust that repair. I have tried plastic welding on expansion tank years ago and it recreated leak in a week's time. Of course it probably matters what type of plastic it is. 

Another truth is, if you never try, you never know. Might find something which lasts for long.

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Diesels run cooler than petrols and the cooling system is under less stress. A bit of applied bodgery is a great antidote to all those 'refresh' sorts who piss away hundreds on new parts the car doesn't need in the vain hope it might be more reliable. 

 

See how long it lasts! 

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On 27/09/2021 at 21:26, Sir Anthony Regents-Park said:

Diesels run cooler than petrols and the cooling system is under less stress. A bit of applied bodgery is a great antidote to all those 'refresh' sorts who piss away hundreds on new parts the car doesn't need in the vain hope it might be more reliable. 

 

See how long it lasts! 

 

Agreed. I inwardly groan when I read of cooling system or suspension "refresh". I have lost track of the parts I have replaced on my car over the 20 years I have owned it but I have only done this when parts have failed or show excessive wear. Things start to wear from day one and unnecessary replacement is a waste of money - and don't get me started on the "my car deserves a genuine BMW windscreen replacement" argument. 

 

As far as my radiator is concerned the crack opened up again but it was only a quick job while a replacement was ordered. I fitted a new unit today. The only problem I had was with the bottom hose which refused to separate from the radiator and I had to break the radiator pipe. It took a good hour with the hose in my vice to free up the broken bit of pipe from the hose without damaging the plastic collar on the hose. The top hose was no problem because I had previously replaced that. These click fitting hoses are great when reasoanbly new but stick like buggary after 20 years of use.

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I think of certain jobs as preventative maintenance though. M54 seems to run warm and header tanks/ pumps fail with age so sometimes its prudence rather than being sat at the edge of a motorway.

 

Suspension is a one that i don;t think you notice the degradation until you do replace stuff amazing how you get used to a baggy car as it ages.

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