How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Robert Your Own Question
Robert, BMW Technician
Category: BMW
Satisfied Customers: 4708
Experience:  Fully qualified 19+yrs exp/self employed technician in the UK
Type Your BMW Question Here...
Robert is online now

318iSE expelling or leaking litres of coolant from the system;

This answer was rated:

318iSE expelling or leaking litres of coolant from the system; diagnosis head gasket; tests support this; gasket replaced; coolant continues to be lost but at a lesser rate; what other possible causes?


Hopefully i can help..

What actual tests did they perform?

Does the engine acutally overheat still / and excessive vapour/smoke from the exhaust?

Have you noted any coolant on the ground under the car since or prior?

Was the cylinder head checked?

Customer: replied 3 years ago.

The mechanic did the 'gas' test twice and on each occasion the testing probe turned to the appropriate colour indicating that there was a 'blown' head gasket. He then changed the gasket but the system has continued to lose water, but not at as high a rate. According to my wife whose evidence is not totally reliable, the temperature did not rise to excessive levels at any time. Coolant was observed on the ground on a couple of occasions. I do not think the head was checked when the mechanic changed the gasket but I am not absolutely sure about this, he is generally honest and reliable. In any case could he judge a warped head simply by observation? I don't think there was exhaust smoke or overheating at any time

Hi..there thanks for your reply..

No sadly you cant diagnose a warped head intially with it on the engine - however it depends on the extent of how the heads warped, that has to be checked if a engine has overheated alot..sometimes you can check with the head on a bench clean off all the old gasket traces and use the edge of long steel rule to check how level the head is..if there are any gaps seen or light comes through between the head and the edge steel rule..even shone torch along the opposite side..either way any gaps/light coming through would be a sign of the heads i say it depends on the extent of the warp or the head itself could even have very small hairline which case the head needs to be tested at a specialist to confirm that..and if the heads at fault then another one has to sourced..

.Yes i know which test you mention in regards ***** ***** test checking for exhaust gas within the coolant system...Have they tried pressure checking the coolant system itself..If as you describe coolant has been seen on the ground then that would be one of things to have investigated at least id say..doing a pressure test on the coolant system can often highlight exactly where the leaks coming from.they need to build up pressure in the system according to the psi on the cap and then check for that leak you talk off..thats most likely why your still loosing coolant at the moment and maybe just showing up when the engine under running temp mostly...But like i say above givin that you have noticed coolant on the gorund on a few occassions i would certainly get them to carefull check and see exactly where that leaking out from and rectify - after which ensure they do bleed the system properlywith the heater set wide open to hot as these do have habit of being pig to somecases having to jack the car up high at the front to get the air out the thats what i do from here certainly try and find out where that leaks is and hopefully once thats fixed or found should stop the coolant loss..I do hope this helps
Robert and other BMW Specialists are ready to help you