Where has all my coolant gone??

[Jon K]

Hey guys, M50B25 motor... I got a "coolant level" ding the other day... figuring i might have a leaky gasket or heatercore thing gone wrong or something, I accepted a little bit of GRADUAL coolant loss... I haven't topped my coolant since this time last year. However, after topping it off, I started the car and drove 130 miles to get home again and have "coolant level" again. Being down the Jersey Shore i had no access to tools or anything so I just kept dropping distilled water in her until finally at home. Now I need to find out what's wrong. I have coolant sprits on the pulley directly below the water pump. This to me says either loose hose or some sort of leak. The alternator pulley has some residue (greenish blueish) on it and there were some small wet spots on my driveway. This doesn't seem to be a headgasket problem. My temperature, even with the leaking coolant never goes above the half-way mark. Is there any common reason why coolant would be falling out of the front of my engine?

[MBXB]

Jon,
Check the water pump and all hoses for leaks? Use a real bright spotlight, like one of those 1 mill candlepower jobs, while the engine is running?

[John 535is (Sydney)]

Water pump has probably failed on the inside. Lets water drip out slowly when engine in running. On the up side, very easy and relatively cheap fix. Takes less than 30 minutes (once the engine has cooled down). While your at it you can check the condition of the belts. Good time to put a new one on and put the old one in the spares box.

John 535is

[Paul in NZ]

I had a split hose......would only lose coolant when runnibg..tell tale was bright(insert the coolant colour of choice here)puddles in traps and crevices visible with a torch.Try squeezing all of the hoses when your in the garage and if you hear a squelching sound you have found the culprit. And Jon check out this (http://www.bimmer.info/forum/showthread.php?t=5803) post,havent you done this?

[WarrenBrown]

Check the thermostat housing also, the original part is plastic, many places sell aluminum replacements. Don't forget to replace any ground wires that are bolted to the front of the engine. The motronic doesn't like them being disconnected.

Warren
91 318is
95 525iT

[philbyil]

Ok...M50 motor and if this is the original water pump...you will need to do the following :
1. Replace the water pump for metal impeller type.
2. Replace thermostat
3. Replace thermostat housing with ALUMINUM housing.
4. Replace your hoses while you are at it.....

All of the above parts can be obtained from BMA.

[Jon K]

I had a split hose......would only lose coolant when runnibg..tell tale was bright(insert the coolant colour of choice here)puddles in traps and crevices visible with a torch.Try squeezing all of the hoses when your in the garage and if you hear a squelching sound you have found the culprit. And Jon check out this (http://www.bimmer.info/forum/showthread.php?t=5803) post,havent you done this?



I checked the two hoses going to the waterpump, they are both not split. I cannot visually see where the leak is coming form. I THINK it's from the waterpump... my engine temperature gauge says its normal, never goind above half way. I keep topping the water off until I can get it fixed. It can't be the head gasket can it?


Paul,

I didn't do an Ipod, I have a CarPC hooked up to a 7" touchscreen and a second Alpine headunit which has a 6.5" LCD... I have an XBox hooked to the Alpine and a computer hooked to the 7"

[bfd]

I have a 90 535i, 5 spd, 96K miles and am having a similar problem. Although I've found some "leaking" hoses, and have since tighten all of them down. I've checked the interior to see if the heater core was leaking and found no leaks anywhere, yet, I still seem to lose coolant.

I've checked everything. Usually, the blue coolant is readily noticeable. I do have the original water pump, but hear no noise and supposedly the water pump on the M30 engine has a metal propeller and is not known to cause trouble. Similarly, the M30 engine has a metal thermostat housing and no leaks there. Any other suggestions of where to look? Thanks!

[e34]

Buy the sealer, u pour it in the radiatior and it worked great for me and my moms car, i was like putting collant like every 5 days but after that it stopped. U can find that in pepboys.

[632 Regal]

dont recommend your Ideas on a BMW board.

just kidding!!! LOL if it worked for you it might work for a lot of others. Great idea!

[Paul in NZ]

sorry Jon my bad

[Jon K]

Examined the engine... looked like the headgasket blew... the area around the headgasket on the frontside of the motor was appeared to be dripping green blue coolant... i pulled the crank case cover on the front side to confirm the gasket was not leaking.. no coolant inside or at the edge of this cover. We pulled the belts and such and replaced:

1) T-stat
2) T-stat housing
3) Water pump
4) Coolant

My car is a 1992 BMW 525i, M50 24v non-vanos... it should have had a plastic t-stat housing and a waterpump wtih a plastic impeller... but it had a metal housing with a waterpump with a metal impeller... anywho, it seems that the gasket on the waterpump that was in there was completely obliterated... it looked like it melted and took shape of the grove that is on the waterpump. I will get pics, but *knocks on wood* so far I think I have fixed my coolant leak after ~75miles no coolant ding. It only took like 35miles previously. Lets hope.

[Geoff Hoad]

If its the original change it now. Most people are lucky that it starts to leak and gives plenty of warning. Becaue whenit does go you risk warping the head if it overheats.

Had the experience of planning to change the water pump, ordering the part from BMW and the day before I picked it up the sodding thing went. Very lucky managed to get the engine temp down quick and no problems. That is if you don't count the tow home... :)