Hi All

I am losing water from my 2001 3 Series touring (318i SE) - I have been advised to change the thermostat as the rad is not getting hot.

I can not find where the water is escaping and a pressure test proved inconclusive. Does anyone know if adding k-seal is a good idea or not? In the past I have owned some vehicles which I have been advised not to add k-seal or rad-weld as it buggers it up.

Any thoughts and/or advice would be appreciated.

THANKS!

k seal will only seal a leak wont it.

thermostat is a popular fault, had the same thing on my car, same engine by the looks, another thing as i had a temp gauge which had a mind of its own was the temp sensor.

both are fairly cheap to do and also fairly easy with a bit of mechanical knowledge.

Regardless of the thermostat or sensor, if I put K-Seal in to stop the leak will it do any harm to the engine and cooling system?

;)

Change the Thermostat/sensor first, then you won't lose any of the K-Seal's quality... I put a bottle in mine in Spring and the needle has NEVER dared to pass half way ;)

Alot of people swear by this k seal ive never used it so i couldnt comment on it

In all honesty I cant see it damaging your engine. I do not suggest it as a solution. Both Thermostat/sensor can be changed in no time at all and YOU can do them both.

The water may not be passing because there is an airlock as well. Open the bleeder valve and raise the car as high as you can safely get it from the front. Fill with water until water comes out the bleed hole and if it isn't coming out, run the engine with the cap off and look for little bubbles in the coolant. Water can only flow if there is a consistent amount and water being heavier then air, air will resume at the top

Right, first hand experience.

We sell Kseal at work and when my 318 was loosing coolant, i thought why not give it a go.

This stuff has copper and ceramic in it. When it sets, it literally sets as hard as glass. The water outlet on the back of the head seemed to be the cause of my troubles. So i decided to replace the plastic pipe. The old plastic had fractured with age, and the Kseal had fused the broken plastic to the inside of the head casting. The was no way to removed it with out taking the head off. I had to cut down the new pipe and make a paper gasket and seal it with gasket cement. Nightmare job.

If yours is the M43 engine, I would suspect the head gasket. I chased a coolant fault around on mine for many months, no CO in the coolant, no oil or cream cheese anywhere. Eventually after replacing most of the plumbing, the new parts held the water long enough for the culprit to finally be found, the head had corroded on number four, just enough to allow the gsket to finally fail.

Propably not what you want to hear, but I would definatley start to consider head gasket. Especially if your hoses are getting hard at normal temps.

Having said all the above, we've had guys buy the stuff to go in K series Rover's and it has fixed those head gaskets, and that's a dog of an engine IMO.

Basically, check out all other stuff before you try it. I'll keep all crossed that i'm wrong.

John.

Update

So I have now owned the car for a few weeks and the past 10-14 days have not required any water - how strange. When I was adding water it never took too much to get to the correct level so am wondering if there were air locks etc which have now cleared.

I am changing the thermostat at the weekend before going to Butlins (3 hr drive) as the rad is not getting hot (so the BMW techies at the garage said). Have not had any issues with over heating since the initial drive from buying the car so am hopeful it is sorted - either that or the BMW is a reincarnation of CHRISTINE and is fixing herself - now that would be handy!

Thanks for the help, Im sure I'll be asking for more advice soon!

Didnt get to change the thermostat - before I had chance the coolant bottle decided to give out (could have been worse). I guess the hot water pressure got too much and blew the seal - had to wait until after Xmas to buy the parts though as had no money left for it but have them now and just waiting for an opportunity to get them fitted.

I wonder if the leak will still be an issue?

Personally I do not use K seal or such like, as the previous post suggest it is very much a short term fix, tends to get put in cars at car auctions, It stops the leak, but tends to bugger up and clog up everything it touches

From personally experience if there is a cooling problem on a BMW, it’s probably the Head gasket on its way out, However it is worth checking the radiator as they do have a tendency to bow at the bottom which can cause all manner of problems!