coolant bottle emptying

geordie1980 · 09-01-08, 01:47 PM

hi all

just wondered if anyone has come accross this. When i fill my coolant/expansion ( on my 1984 80 saloon) tank it seems to be dry almost immediately after a decent run yet shows no signs of overheating. The previous owner says this was always the case and he had no problems just wondered if this was normal? sounds dodgy to me.

The hoses coming from the tank seem fine so i can only assume a leak in the rad but, as i say there appears to be no overheating problems even on a long run.

thanks

john

Coxy · 09-01-08, 02:09 PM

hmmmm, must be a leak somewhere for it to be losing that much water. It might only be a small leak in the rad which isn't noticeable on standstill but when being driven and the engine gets hot and there's a lot of pressure in the system, then it would lose quite a bit of water.
A quick fix would be to drop some rad weld into the tank and run the engine for 15. I had the exact same problem with My T25. For nearly a year, i'd have to top up the tank after after run but could never find a leak. I poured in the some rad weld and have never had to top it up since.

randall977 · 09-01-08, 03:18 PM

Another common place for a leak is the hose connection at the rear of the block which feeds the interior heater matrix. It's quite well hidden at the back and the coolant can trickle down over the gearbox - though there is oftern a puddle on the ground to indicate this. Is any coolant on the ground after the car has been parked a while?

TheTwelveQuidKid · 09-01-08, 08:46 PM

I had a mystery water loss on my old BMW 525e last year. As with this, there were no obvious signs of a leak anywhere. The only clue was this. When reversing the car out of the drive (after it had been parked up overnight) there was a small trail of water, which seemed to come from the bellhousing. I can only guess, because I didn't investigate further, that it may have been one of the core plugs on the rear of the engine block, which was only accessible with the gearbox removed. Because it wasn't losing much water (less than a pint a week) I didn't bother about it.

I've always been wary about using radweld after it blocked the thermostat in a 1.6 Audi.

Coxy · 09-01-08, 09:53 PM

Now you've said that, just another thought as I've just had to deal with a similar thing on my BMW, and that turned out to be a very small crack in the head gasket and the water was trickling out at the end of the block. The way I sourced where the leak was coming from was to give the engine a good clean, then leave her running for 20 minutes and then getting under the car and seeing if I could see a signs of a water trail as most of it will turn to steam before it drips onto the floor so you won't hardly notice the leak anyway.

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09-01-08, 02:09 PM	#2
Coxy 4 Ring Mafia Classic Audi Club Member Join Date: Jul 2007 Location: on the side of a hill in Shropshire! Posts: 28,215	hmmmm, must be a leak somewhere for it to be losing that much water. It might only be a small leak in the rad which isn't noticeable on standstill but when being driven and the engine gets hot and there's a lot of pressure in the system, then it would lose quite a bit of water. A quick fix would be to drop some rad weld into the tank and run the engine for 15. I had the exact same problem with My T25. For nearly a year, i'd have to top up the tank after after run but could never find a leak. I poured in the some rad weld and have never had to top it up since.

09-01-08, 03:18 PM	#3
randall977 Mr Typ 43! Classic Audi Club Member Join Date: Sep 2007 Location: Oxfordshire Posts: 838	Another common place for a leak is the hose connection at the rear of the block which feeds the interior heater matrix. It's quite well hidden at the back and the coolant can trickle down over the gearbox - though there is oftern a puddle on the ground to indicate this. Is any coolant on the ground after the car has been parked a while?

09-01-08, 08:46 PM	#4
TheTwelveQuidKid Grown up member Join Date: Dec 2007 Posts: 422	I had a mystery water loss on my old BMW 525e last year. As with this, there were no obvious signs of a leak anywhere. The only clue was this. When reversing the car out of the drive (after it had been parked up overnight) there was a small trail of water, which seemed to come from the bellhousing. I can only guess, because I didn't investigate further, that it may have been one of the core plugs on the rear of the engine block, which was only accessible with the gearbox removed. Because it wasn't losing much water (less than a pint a week) I didn't bother about it. I've always been wary about using radweld after it blocked the thermostat in a 1.6 Audi.

09-01-08, 09:53 PM	#5
Coxy 4 Ring Mafia Classic Audi Club Member Join Date: Jul 2007 Location: on the side of a hill in Shropshire! Posts: 28,215	Now you've said that, just another thought as I've just had to deal with a similar thing on my BMW, and that turned out to be a very small crack in the head gasket and the water was trickling out at the end of the block. The way I sourced where the leak was coming from was to give the engine a good clean, then leave her running for 20 minutes and then getting under the car and seeing if I could see a signs of a water trail as most of it will turn to steam before it drips onto the floor so you won't hardly notice the leak anyway.