dimsim 2 Report post Posted July 26, 2016 I've read of some the common issue with these, expansion tank, radiator side tanks, temperature sensor o'ring and dont seem to have any of these problem. There is a tiny little bit of white residue on the expansion tank but it doesnt seem to get bigger yet i still lose maybe 100-200ml over an open road journey of about 50km. I read here that the heater matrix can also be a problem but dont have a coolant smell inside and dont appear to have any water inside either. Ive had a good look around the block and cant see anything obivous. I did take than fan and shroud off and had a good look on the inside of the radiator and it looked clean and dry - should it take it right out and look from the other side? Does anyone have any other suggestions in what to look for? Thanks Very small amount of white staining at top of radiator header tank Header tank stain up close Expansion tank looks fine Quote Share this post Link to post Share on other sites
gjm 3258 Report post Posted July 27, 2016 Keep praying it's not the heater matrix... I didn't find any damp inside the car, but I could smell coolant so hopefully that'll not be your problem. Quote Share this post Link to post Share on other sites
Rubix 434 Report post Posted July 27, 2016 Do you hear any bubbling/gurgling from the expansion tank right after you shut the car off? If there's residue on the expansion tank then there's coolant leaking - could be a failing tank cap, or possibly something like the heater control valve failing and causing over-pressurisation (hence buggling/gurgling) of the system, making it bubble out the top whilst driving, I had this exact issue in my M54 after replacing the entire cooling system, failed HCV was cause. On your dash (with car running), hold the trip meter in until it flashes into test mode (About 5-7 seconds), click it until the number hits 19, wait one second, click it again to put it into test mode (19.1) then click it to 7 to show current coolant temp. useful for open road driving to see if you're overheating at all. Quote Share this post Link to post Share on other sites
allan 295 Report post Posted July 27, 2016 Two things spring to mind,1. the "O" rings used to seal the radiator hoses they can become deformed also become hard. 2. A crack in the internal skin of the expansion tanks not common. Get the cooling system pressure tested when it is cold Quote Share this post Link to post Share on other sites
dimsim 2 Report post Posted July 28, 2016 On 27/07/2016 at 6:03 PM, Rubix said: Do you hear any bubbling/gurgling from the expansion tank right after you shut the car off? If there's residue on the expansion tank then there's coolant leaking - could be a failing tank cap, or possibly something like the heater control valve failing and causing over-pressurisation (hence buggling/gurgling) of the system, making it bubble out the top whilst driving, I had this exact issue in my M54 after replacing the entire cooling system, failed HCV was cause. On your dash (with car running), hold the trip meter in until it flashes into test mode (About 5-7 seconds), click it until the number hits 19, wait one second, click it again to put it into test mode (19.1) then click it to 7 to show current coolant temp. useful for open road driving to see if you're overheating at all. Thanks Ill try that. I did just buy a iCarsoft i910-II and found I could query the engine sensors. I did notice that one of the cooling system temps was 144 degrees! Is that temp that's within spec of normal use? I however noticed the coolant level drop again overnight so I removed the lower engine cover off and found a drip! Pulled it all apart again today and took the belt and pulley off the water pump and saw a drip coming from the hole in the bottom - phew... so guess its a water pump. Certainly couldn't see any leaks form the thermostat housing. I gave the water pump pulley a bit of a shake to see if it that was where the leak was and now after putting it back together its seems to be spewing al lot more water out with the belts and fan flicking it all over the place...! I suppose this is new as I have noticed this before when the engine was either hot or cold. Have a water pump hopefully arriving tomorrow, so will replace and hopefully that is that! Will update after. Quote Share this post Link to post Share on other sites
dimsim 2 Report post Posted July 28, 2016 22 hours ago, allan said: Two things spring to mind,1. the "O" rings used to seal the radiator hoses they can become deformed also become hard. 2. A crack in the internal skin of the expansion tanks not common. Get the cooling system pressure tested when it is cold Thanks Allan - I've looked and looked all around the hoses, tanks, radiator, temp sensors for leaks and haven't found a thing. After looking at youtube videos of other E46's I've realised that mine is actually quote tidy. Anyway as per above it looks like it was a small leak form the waterpump that wasn't visible until taking the pulley off as it was water travelling from the WP down the front of the head/block then dripping onto the bottom engine cover. Hopefully have it sorted tomorrow Quote Share this post Link to post Share on other sites
dimsim 2 Report post Posted July 28, 2016 (edited) On 27/07/2016 at 1:09 PM, gjm said: Keep praying it's not the heater matrix... I didn't find any damp inside the car, but I could smell coolant so hopefully that'll not be your problem. Yeah I know what you mean. I was working at Shelly's when I had to do a recall that required the removal of a brand new E36 dash. While it was quite cool to take it all apart and get it back together you never know if you going to end up with any nasty rattles or squeaks! Actually that one was a breeze, I must have been the dash specialist as the next one I got was a Citroen - if you've ever had one of those out you'll know what I mean by "how many green wires does this thing have!" The French must have been colour blind. Edited July 28, 2016 by dimsim 1 Quote Share this post Link to post Share on other sites
Olaf 3317 Report post Posted August 13, 2016 Graham, whats the story with the heater matrix? I am getting a whiff of coolant at startup, and am closely monitoring coolant use now. Everything under the bonnet has been replaced except radiator (water pump, pulleys, sensors, thermostat, expansion tank, rad hoses). cheers... Quote Share this post Link to post Share on other sites
jom 98 Report post Posted August 13, 2016 Heater valve? Quote Share this post Link to post Share on other sites
gjm 3258 Report post Posted August 14, 2016 3 hours ago, Olaf said: Graham, whats the story with the heater matrix? I am getting a whiff of coolant at startup, and am closely monitoring coolant use now. Everything under the bonnet has been replaced except radiator (water pump, pulleys, sensors, thermostat, expansion tank, rad hoses). cheers... The heater matrix is the first component used in the build of an E46. This is place in on the floor, and incidental things like the chassis, suspension, interior and so on are then bolted to it. This means replacement is a major job. OK - it's not quite that bad, but to replace the heater matrix in an E46 requires removing the front seats and the entire front dash with all controls and so on. Basically, strip the interior from the front end of the car. 2 Quote Share this post Link to post Share on other sites
Young Thrash Driver 1020 Report post Posted August 14, 2016 Eh, BMW's have cooling issues? Since how long has that been a thing??? If all it is is a waterpump, then I'd say that's as good as winning Lotto Quote Share this post Link to post Share on other sites
zero 1162 Report post Posted August 14, 2016 Did the waterpump replacement fix the problem? Quote Share this post Link to post Share on other sites
dimsim 2 Report post Posted September 6, 2016 (edited) Yes, pump was leaking from the little hole underneath and dripping down the front of the engine but so was the radiator tank by the top hose. In the end replaced the radiator and the water pump and all good. Was pretty tricky to determine if the radiator was leaking as it's kind of hidden but for future reference is anyone see's any white staining around that area then its likely it needs replacing. I guess a pressure tester would have picked this up but I didn't have one. The radiator leaking was pretty evident after I had done the pump and replaced the coolant, as there was fresh coolant under the top hose at the radiator. With cooling systems in these being an issue my recommendation would be if you are doing a radiator, do the pump at the same time and if you doing a pump make sure you take the radiator completely out and inspect it carefully along with the expansion tank. Edited September 6, 2016 by dimsim Quote Share this post Link to post Share on other sites
