Coolant level dropped quickly

babel

Hi Guys,

Have my car (318ci) booked in with AC Car sales for this weekend but I was hoping to get some opinions on how bad the problem is in the mean time.

I checked the coolant level on Sunday and everything looked fine. Went for a drive that evening and also on Monday. On the way home Monday evening the low coolant light came on. When I got home and checked it the coolant had dropped to 0! I filled it this morning and 5 minutes down the road it was empty again. Filled it again, left the car at home and took the train to work. The driveway seemed to be wet under the car but I am not sure if it was wet enough to empty the tank.

Any ideas what could have caused the coolant level to drop so quickly?

Thanks

uprooted shane

now i dont know much about cars, but this seams very werid to me, when you did check it, how hot was the car and was it left running?

what im thinking is, and i dont even know if its possible, but if the car was over heating, it might be drawing so much from the coolant that its evaporating it, but then again, fiveminutes to do that is a bit mad!

sham08

My 316i does this as well but I don't have any wet patches below my car ever, but I have to top up the coolant every 1-2 weeks. I have brought it to a garage and they ran it for 2hrs at high revs to see if it would overheat which it didn't, the bloody coolant didn't even drop so they couldn't do anything with it. But regularly when I'm caught in traffic the temp starts increasing. I can't understand why the coolant disapears if it doesn't leak out of the engine at all

BrianD3

Wet patch under the car and dropping coolant is often due to a water pump leak. I have seen water pumps which leaked a bit and ones which leaked a lot.

Even if the tank has emptied there may still have been a significant amount of coolant in the system.

mike65

Any signs of white smoke on a warm engine? If there is the coolant getting inside the block I would say.

Sometime you loose coolant through a tiny leak in the rad that causes the liquid to dissapear as a little stream of steam which may not be obvious.

Mike.

sham08

Do you have to replace the rad then or is there something you can put into the rad/ coolant?

DublinDilbert

Is it an E36 or E46??

If its an E46 it sounds like it could be the expansion tank which is cracked... based on the amount of water your describing it should be very easy to spot where its coming from.... pop the bonnet and have a look....

rebel.ranter

I'd prefer to see a puddle under the car if the coolant is going down. At least then you could blame a burst/cracked pipe (€50) or a loose connection (€3), or a damaged radiator or expansion tank (€200), or a cracked thermostat housing (€30). The other option could be a faulty radiator cap (€6), it may be letting off pressure too soon, with the water escaping as steam. There was a recall on a lot of 1980s/1990s BMWs with this issue.

However the final possibility is a failed head gasket (€500- €1000 incl. labour). This failed gasket allows water to move in to oil ways and/or combustion chambers. This is the most expensive problem to rectify. in my opinion the car is never the same with a replaced head gasket. That's just my opinion.

Check the underside of your oil cap. Normally one of the tell-tale signs of a blown head gasket is a mayonaise-type substance on the base of the oil cap. It's basically water & oil mixed.

Good luck.
(approx parts prices in brackets)

babel

Thanks for the responses...

It is an E46, the water temp guage in the car stays right in the middle all the time and I have not seen any smoke come out of the engine at all. I am hoping there is just a leak in a pipe or something, not a blown head gasket!

sham08

Its an 1997 E36.

I have never seen any white smoke coming out of the exhaust and the oil is always jet black so I don't think there is any coolant getting into the oil. But the oil level does drop somewhat I put in 1.5litres about 2 months ago and it does seem to have dropped somewhat since then, but again no oil patches under the car.

sham08

babel wrote: »

I am hoping there is just a leak in a pipe or something, not a blown head gasket!

+1

rebel.ranter

sham08 wrote: »

......the oil is always jet black so I don't think there is any coolant getting into the oil...

Check the base of the oil cap.

Oh forgot to mention above the the radiator drain plug seal coudl eb gone, the plug itself is normally blue in colour, it's €2 to replace. It was one of the cheapest faults I had to fix!

Tails142

please tell me 'cracked thermostat housing (€30)' is a typo - I paid 300 in a garage recently =D

rebel.ranter

Tails142 wrote: »

please tell me 'cracked thermostat housing (€30)' is a typo - I paid 300 in a garage recently =D

Eurocarparts.com do them for £30 STG (so a semi- typo), housing only. It's about €120 for housing & thermostat together at the main dealers. Did that €300 price include labour, new thermostat, new coolant?

Eoin

rebel.ranter wrote: »

I'd prefer to see a puddle under the car if the coolant is going down. At least then you could blame a burst/cracked pipe (€50) or a loose connection (€3), or a damaged radiator or expansion tank (€200), or a cracked thermostat housing (€30).

This is exactly what happened to me - had a cracked pipe (they are only plastic) and a leak in the thermostat housing. My coolant light was coming on after about 30 mins. I had my water pump replaced a few weeks before. The garage said that this could have restored the full pressure of the coolant system, causing some parts that had been there for 120K miles to go.

JimmyCrackCorn!

rebel.ranter wrote: »

Eurocarparts.com do them for £30 STG (so a semi- typo), housing only. It's about €120 for housing & thermostat together at the main dealers. Did that €300 price include labour, new thermostat, new coolant?

Its a pain of a job depending on the car and how bad access to it is. Did my thermostat last Friday. 300euro is allot. Was it a main dealer?

OP any sign of smoke or steam. Any puddling(get car to temp and running to look for leaks). Do you know how to use a compression tester. Is there any sign gunk on rad cap or oil cap?

Water pumps are designed to leak as a sign they need changing/refurb.

Check all this out.