COOLANT IN THE TRAY BELOW THE ENGINE
- Thread starter Robert63
- Start date
Attleborough, Norfolk
Robert63 said:
I recently spotted something similar in my wife's car. Turned out to be the seals in the bottom of the expansion tank.
However, that was all on the passenger side (RHD), so unless you have evidence of it running across I guess yours must be a separate issue.
EDIT: Just dug around to discover yours is a 2.2. A google of the engine bay seems to show the expansion tank on the drivers side, so maybe it is that? No real way to be certain without getting the under-tray off and having a good look up there.
Don't get me wrong I bloody love driving the car, and yes she is old now but only done 75k mileage genuine with full service history. And when washed and polished still looks stunning . To get something newer would cost a lot more, it was me having a bit of a rant that's all. I don't think the leak is coming from the headlights because the car hasn't left our garage since January. Thanks everyone.
Robert63 said:
Have you had it running?
Usually the expansion tank only starts to leak when the water gets hot and pressure increases.
If it has sat for that long then it is more likely to be a seal somewhere.
Only caveat I'd put on that is that a very slow leak would usually be drying as it went and you'd be more likely to see dry deposits where it has evaporated.
As I said before, tray off and under you go with a strong torch.
All M54 engined Z4s (2.2, 2.5 & 3.0) have the same cooling system with the expansion tank down the side of the radiator on the nearside/passenger side (UK cars)enuff_zed said:
I had a leak a few years back from the o-ring on the temp sensor that is mounted at the top end of the radiator bottom hose just where it is connected to the thermostat housing. It is number 5 in this diagram
The leaking coolant runs down the underside of the hose and drips on to the undertray at the front drivers side of the engine. You can replace just the o-ring or the complete sensor. A bit tricky as access is quite tight and you may lose some coolant. I fitted a new sensor with green Viton o-ring that I bought on Ebay for about £8
patriot66 said:All M54 engined Z4s (2.2, 2.5 & 3.0) have the same cooling system with the expansion tank down the side of the radiator on the nearside/passenger side (UK cars)20200605_162743.jpgenuff_zed said:
I had a leak a few years back from the o-ring on the temp sensor that is mounted at the top end of the radiator bottom hose just where it is connected to the thermostat housing. It is number 5 in this diagram20200605_162805.jpg
The leaking coolant runs down the underside of the hose and drips on to the undertray at the front drivers side of the engine. You can replace just the o-ring or the complete sensor. A bit tricky as access is quite tight and you may lose some coolant. I fitted a new sensor with green Viton o-ring that I bought on Ebay for about £8
20200605_164145.jpg
Thanks for the clarification. I had no experience of the 2.2 so googled it. The engine bay images appeared to show the expansion tank on the drivers side, hence my posts earlier. I hope this hasn't mislead the OP?
I’ve just checked the coolant tank. I topped it up couple of days ago. And this morning it was completly dry in the tank and all coolant was in the tray under the engine. Normally it was never that bad . It was always between maximum and minumum levels. I just had to top it up every couple of weeks. Hope it won’t be an expensive fix
Coldquest said:
Well I just had exactly the same issue on my wife's 2004 2.5i auto.
I believe it was probably the o-ring seals in the bottom of the expansion tank where it push fits onto the manifold below it. However, for all the faff of getting it out, I wasn't prepared to risk putting it back together then finding the tank was leaking, so I bought a new one, which came complete with seals.
On advice from people on here I also changed over the o-rings in the hose connections that I had to remove. Luckily I had a big box full of various sizes.
One issue that slowed me up; I removed the old expansion tank and as I turned away I heard a crack. There's a thermostat sits in the bottom of the manifold, held in place by the tank. Obviously the plastic had weakened and the spring inside blew it apart. So I had to wait a few days for a new one.
I am not sure if this is only fitted to automatics though? Something to do with cooling the transmission oil I think?
Best to find out though, and have a new one ready if you need it.
It wasn't a difficult job and there's loads of tutorials on line that I referred to.
Robert63 said:
I used a trolley jack and lifted it onto axle stands. But to do that I had to lift at the rear jacking point until it was high enough to put the stand under the front one. Fine for the first side, but on the second side there comes a point where the car is balanced on just the axle stand and the jack!!!
So I've since purchased a pair of ramps.
Another option is to run it up on some suitable planks?
I used axle stands so I could get the wheels off, as it let a bit more light in, but in hindsight you can leave the wheels on and run it up on blocks or ramps.