Leaking Coolant?

[chunho01]

Neverending issues dear car please..

So I have:

1. June 16 Changed waterpump and thermostat
2. September 16 Fixed VCG and OFHG leaks
3. September 16 Changed radiator hose to fix major coolant leak

Two days ago, low coolant warning came on and I topped up with distilled water (I usually top up 50/50 bmw coolant, but I was in a rush).

This morning I found streams of coolant near the front of engine (cold engine; overnight). Can anyone share some thoughts?

(Ignore the dried up coolant splatter spots and focus on the wet streams; dried up spots were from the radiator hose leak back in Sept 16)

[HyeWarrior]

Willing to bet it's a cracked expansion tank.

Changed my water pump, thermostat and U pipe at 56k miles. Expansion tank needed to be replaced at 58k miles due to a similar mystery leak.

Good news, fairly easy and cheap fix.

[chunho01]

Originally Posted by HyeWarrior

Willing to bet it's a cracked expansion tank.

Changed my water pump, thermostat and U pipe at 56k miles. Expansion tank needed to be replaced at 58k miles due to a similar mystery leak.

Good news, fairly easy and cheap fix.

Expansion tank is not near that area though?

I went out to check the engine bay just now, found a droplet (after parked for 4 hours). I also noted that the coolant hoses and expansion tank are still warm to touch.
Do they normally take so long to cool?

titium vtl , tagged you guys because you replaced similar items before. Ideas?

[vtl]

Cylinder head to thermostat hose. The plastic flange crumbles over time and leaks. Buy a new hose asap before it gets worse. Very common problem, mine cracked on the racetrack lol, lucky its high up in the system so you can keep topping up.

Should be 11537552339 but double check it yourself as I dont know the exact car you have.
http://www.realoem.com/bmw/en/showpa...diagId=11_3755

[chunho01]

Originally Posted by vtl

Cylinder head to thermostat hose. The plastic flange crumbles over time and leaks. Buy a new hose asap before it gets worse. Very common problem, mine cracked on the racetrack lol, lucky its high up in the system so you can keep topping up.

Should be 11537552339 but double check it yourself as I dont know the exact car you have.
http://www.realoem.com/bmw/en/showpa...diagId=11_3755

True, you can see a bit of moisture near the rubber joint in the photo too. I felt it with my hand but it wasn't wet wet though.. maybe over time.

One other concern is, during the major coolant leak before (one of the hoses cracked badly), I had to top up with tap water just so that I could drive it to work, then top up with more tap water to drive it to the mechanics.

I checked the invoice now and don't see any coolant flush, so it might be tons of tap water in my cooling system now. Would that cause the cooling system to over-pressurise, and cause leaks near weak joints?

[chunho01]

Silly me，now that I think about it， coolant must`ve been flushed， refilled and bled during the radiator hose replacement back in September. No other way they can remove that hose without flushing.

Water expands much more than coolant， that's why I was worried it would overpressurise if it is just water inside.

Back to topic， how hard it is to replace that Cylinder head to thermostat hose? The lower section seems quite hard to access without removing a lot of parts.

[Dackelone]

Originally Posted by chunho01

Back to topic， how hard it is to replace that Cylinder head to thermostat hose? The lower section seems quite hard to access without removing a lot of parts.

You probably should also replace the water pump, thermostat(and pump bolts, they are a one time use) and U-shaped coolant hose - while your in there. It's not that hard of a job... but things are tight and its a whole lot easier on a lift.

I had my local BMW Zentrum(dealer) do my water pump & thermostat replacement - mainly bc I wanted the BMW two year warranty(good thru out Europe) bc I often drive off "the beaten path". I think my dealer charged me two hours labor to replace the pump/thermostat/hose/coolant.

The expansion tanks do crack... so it also might make sense to replace it too. Just look around the engine bay... IF you see some white marks... thats dried up coolant. So check your cooling system out.

[chunho01]

Originally Posted by Dackelone

You probably should also replace the water pump, thermostat(and pump bolts, they are a one time use) and U-shaped coolant hose - while your in there. It's not that hard of a job... but things are tight and its a whole lot easier on a lift.

I had my local BMW Zentrum(dealer) do my water pump & thermostat replacement - mainly bc I wanted the BMW two year warranty(good thru out Europe) bc I often drive off "the beaten path". I think my dealer charged me two hours labor to replace the pump/thermostat/hose/coolant.

The expansion tanks do crack... so it also might make sense to replace it too. Just look around the engine bay... IF you see some white marks... thats dried up coolant. So check your cooling system out.

Thanks Dac! Waterpump and thermostat were replaced in September. I got the 2 years warranty as well.

Now this hose is playing up... So I'll be only looking at replacing this hose.

It's only leaking a few drops at night now， thinking of delaying it a tad bit longer after Christmas...hmm...

[juld0zer]

Engine oil destroys EPDM rubber - makes it all soft and fat. You had a leaky OFH and the oil has worked its way down and weakened the rubber.

As for tap water... most workshops dont use distilled water. Big dealerships have fluids on guns and the coolant concentrate is pumped into a holding tank together with a set volume of tap water so it's ready to be dispensed via the guns. However, i top up with distilled water.