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Discussion Starter #1
I seem to have picked up a coolant leak! :grrrrr:

Here's the narrative:

Recently had an Inspection I plus brake fluid and coolant change. Shortly after getting the car back, I had to take the wife to the airport (2 weeks ago). Jumped in, fired the old beast up and promptly got bonged with a check control "coolant level" warning. Switched off, pulled the bonnet catch and jumped out again to check the level of the expansion tank.

Level appeared to be okay at the 'cold' mark. Unscrewed the cap to check that little air purging nozzle to see if it was 'dribbling'; all okay. Had a quick check of all the water hoses (the ones I could readily see that is!). No noticable leaks. Scratched my head for a few seconds, replaced cap, closed the bonnet, jumped back in and drove to Gatwick.

On the way there and on the return everything appeared to be okay. Coolant and oil temp. normal. Got back home, parked up and left it to cool down. The following day or the day after, I checked the level again in the expansion tank. This time it was low, below the cold mark but not empty. So, just topped it up with a liittle bit of water. A couple of days after that, took her out for a spin...no more bongs. Great, problem solved!:)

Wrong! Drove the machine to work yesterday evening and left it parked up for about 12 hours. This morning, I noticed a wet patch on the ground just below the front spoiler and to the right, towards the driver's side (LHD). Dabbed the patch with a tissue and noticed blue tinged stain. A coolant leak somewhere? Jumped in and started her up...bong! Coolant level warning again.

As I was tired and just wanted to get home, I took the risk and drove it. Nothing untoward happened on the way back; coolant and oil temp. normal. Got back, left it for a couple of hours whilst I picked up a few parts from the stealers. When I returned, decided to give it another check.

The wet patch has appeared again, the expansion tank is virtually dry, but all main water hoses appear to be intact. However, as I peered downwards between the the air box and oil filter, I noticed that the radiator well - just below the oil cooler - is wet with coolant. It also looks like coolant has sprayed across the alternator air duct and further towards the rear onto the front axle support. The inner part of the front wheel is also exhibiting signs of coolant spray.

Gentlemen, I maybe wrong but I think it might be the radiator. Apologies for the narrative being a bit stacatto, I'm just a little tired zzzzz at the moment (just finished nights), but any advice and comments will be greatly appreciated as always.

Kurt
 

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My advice:

dont drive it again until the problem is rectified. You've been extremely lucky so far not to overheat and cook your motor.
 

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Discussion Starter #3
Quick update.

After leaving the car to stand for about 6 hours this afternoon, I checked the expansion tank coolant level again. The tank seems to have refilled itself to just below the cold level mark – has the system re-pressurized or de-pressurized itself? :dunno:

Anyway, turned on the ignition and got bonged again. So, took off the expansion tank refil cap and topped up with just under 1 ltr of de-ionised water (did not have any approved anti-freeze available). Turned on ignition again; no bongs!

Obviously, the leak appears to occur when the engine is running and under load and shortly after switching off.

Really don't know what to make of this fellas; so it's off to the local dealers to see if they can diagnose the problem.

Will keep you posted on this.

Kurt
 

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Good morning Kurt,

Have you pressure tested the radiator? Have you replaced all hoses and any gaskets that may have failed? Have you checked the coolant temp sensor for leaks around where it screws in or perhaps the unit itself leaks when it gets hot? Have you checked the thermostat housing for leaks? (Had that problem with my 540, loads of fun to diagnose but once found made all the difference in the world). Have you tried the "Black Light" trick? (I think your "blue" coolant will still luminesce). Have you pressurized the system and crawled around looking for the what sounds to be pin hole leak? Good luck and Happy Motoring
 

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Discussion Starter #6 (Edited)
Sorry fellas, I don’t have the facilities or the wherewithal to pressure test the radiator. All the water hoses seem fine and don’t leak when the engine is running. I’m still sticking to my theory that it is a very small hole in the bottom right (drivers) side of the radiator.

<O:p</O:p
I could of course be wrong, but from flash (first check control warning) to bang (second check control warning and lack of coolant in the expansion tank) has taken about 10 days.
<O:p</O:p
Thanks for the replies so far. I will keep you posted on the eventual outcome.

Kurt
 
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