348 Coolant Overflow / Leak - Help :(

Hi all. After running my car up on the drive earlier, noticed a puddle underneath, coolant! I have traced it and it came out of the overflow pipe that originates at the header tank neck. It dawned on me that I had had the filler cap off when cleaning and hadn't secured it fully, ie only screwed it on half it's travel. I have secured it properly and reset the level, (6cm under the neck whilst cold). I re-started the car, let it run and when up to temperature, coolant, a fair amount streaming from the overflow. Does anybody have any ideas? Now majorly concerned...No sign of cross contamination in either the oil or coolant. Fan is running fairly early on. Not sure what the temperature should reach before going back down again, but had the car at approx the 3/4 mark before I turned it off due to the overflow.

Thanks

Paul

 

Thanks for the reply. Do you know what fans should be running and when out of the 3 fitted? Temperature seems to be running too high and I don't want to let it overheat. Seems the coolant is coming out the overflow everytime it comes up to temperature / pressure so I think I do have a problem. Hottest I have let it get is 3/4's before turning off. Could this be coolant cap related?

 

I have seen them, 2 I think. Although the tank wasn't completely empty before top up and I had completed a hundred mile trip without any temperature issues, although at a fairly constant speed, no real traffic, so not sure it is air. This may sound obvious, but can somebody tell me out of the 3 fans, which is water, and which is oil? Are both fans (water/coolant) meant to run at the same time? Is there any tests I can make?

Thanks


Paul

 

Thanks for taking the time to reply. I think I may be nearer the source of the problem. I have seen the oil cooler fan run, but not noticed then coolant fans work. I have looked at the fusebox in the passenger footwell and noticed that the LH fan fuse has blown, so i'm wondering if this fan not running is causing the car to heat up too much on idle, hence the coolant is expanding more than usual and coming out the overflow. Does this sound likely?

I have only recently purchased my car, and the only drive was 100 mile trip home, all at a good speed and not ever stationary for more than 2 minutes, so I guess cooling wouldn't have been an issue due to the constant airflow through the rads. This problem has only appeared since letting it idle on my driveway. As it stands, I cannot get more than a 3cm of water in the expansion tank without it overflowing, and the temperature just keeps on rising to a point i'm not comfortable and switch off. Hopefully this makes some sense

Paul

 

Incase this is any use to anybody, my leaks are now all gone

It was a combination of things. The fuse had blown for one of my cooling fans, so on idle, the car was running warmer than usual, causing the coolant to expand more than normal, exiting through the overflow. After this, I was paranoid so put some cardboard under the car to seek out any other leaks!

I then noticed another leak, seemingly directly below the waterpump (you can imagine my thoughts at this point..!) The hose that joins to the heater feed pipe (short 's' shaped hose behind the air plenums) had a slight tear around the jubilee clip. I then thought I would check the remaining hoses. What I did notice at this point was that the coolant tank hose was slightly damp. This again was damaged under the jubilee clip where it attaches.

Both hoses replaced with silicone, proper clips, system blead, nice steady temperature and no more leaks! Just for good measure, I have also replaced the coolant cap!

Thanks all for your help and hope this helps somebody else in future. On the next service I am having all remaing hoses changed!

Paul