carl0s Posted October 14, 2007 Share Posted October 14, 2007 Does anybody know anything about these motors? I found bimmerforums.com or whatever ages ago, but the signal to noise ratio is too low to be useful on there, coupled with lots of model differences, and general yankiness (LHD differences). Our 318i is showing some funny signs. A while ago whilst driving I noticed the temperature gauge creeping up from its usual 50% position to 75%, 80% whilst stuck in traffic. For the rest of the journey (a 2hr journey off camping), it was perfectly fine whilst the car was moving, but once stuck in traffic it started creeping up again. I decided we must be low on coolant, and after arriving and allowing the engine to cool off/depressurise, I had a look and the plastic expansion tank/end tank whatever it's called, which has a hot/cold fill point on it, well the level was right at the bottom, when it should be near the top. So I added some water & ethylene glycol coolant mix. All seemed fine then on the way home, but I have noticed since that there may be a leak. Not seeing any signs on the driveway or anything, but I go back to the car a few weeks, maybe month later, and the level is back right down again. I googled, and leaking radiators is a common problem because the plastic (looks like HDPE) end tank is mounted to the radiator with clips/gasket, and these seals apparently perish after time. It's a funny setup, because this end-tank thing is actually part of the radiator, and the radiator-cap is fitted to this tank, not the metal parts of the rad. So anyway, there's that. A possible leak, but here are the odd things: The interior heaters work then don't work. When the engine temp apparently goes mental, the heaters stop blowing hot air. Then during the journey the temp needle will go back to 50% and we'll get hot air again. I had decided that perhaps we were really low on coolant and that it wasn't flowing through the heater matrix properly. Now yesterday, on our way to York, we got it all again, except that this time the temperature needle seemed dead half of the time. It was at zero (actually, below zero, as if the ignition is turned off). Then it would go to 50% like it should, then whilst stuck in stationary traffic it would go : dead, mental (80%), then a little closer to 50% (normal), then mental, then it'd die again. Before departing York, I checked the radiator and the coolant was right down to the bottom again, so I topped up, but it only took about half a litre to bring it back to the "COLD, FULL" point, which isn't much really is it? Unless there were air pockets everywhere and an empty heater matrix? The needle remained dead (-10%) for good portions of the 1hr30 journey home. Does anybody have a clue?!? cheers! Here's what the radiator looks like. You can see the plastic end tank on the left of the picture, with the frosted white filling part: Quote Link to comment Share on other sites More sharing options...
absz Posted October 14, 2007 Share Posted October 14, 2007 the water pump on the bmw's have a plastic propeller and is very common for them to fail. which will cause overheating and poor heater output due to lack of circulation. run the engine without the rad cap if the coolant starts over flowing within the first few minutes of engine running then i'll put it down to the water pump. also place your hands around the heater pipes and the pipes will feel cold. Quote Link to comment Share on other sites More sharing options...
carl0s Posted October 15, 2007 Author Share Posted October 15, 2007 the water pump on the bmw's have a plastic propeller and is very common for them to fail. which will cause overheating and poor heater output due to lack of circulation. run the engine without the rad cap if the coolant starts over flowing within the first few minutes of engine running then i'll put it down to the water pump. also place your hands around the heater pipes and the pipes will feel cold. Thanks abs. I'll give this a go. What's the theory behind the overflowing with no cap test? Quote Link to comment Share on other sites More sharing options...
Guest InnocentSupra Posted October 21, 2007 Share Posted October 21, 2007 Try http://www.bmwland.co.uk by far the most visited BMW forum in the UK. Quote Link to comment Share on other sites More sharing options...
creative Posted October 23, 2007 Share Posted October 23, 2007 Try http://www.bmwland.co.uk by far the most visited BMW forum in the UK. not quite! right fella..... your initail symptons of the temp rising in traffic is the viscous fan on its way out. The temp staying low once running is the stat stuck open. Where does it look like the leak is from? have a look around the stat housing as these are plastic and do fail (only a tenner from gsf) Might be worth just changing the viscous fan, stat and housing and the waterpump. All fairly common to fail on these. If that doesnt solve it you may have a blocked heater matrix but odds are replacing the other bits will fix it. dont forget the viscous fan nut is lefthand threaded. Is it an M40 engine? if so I know my way round these pretty well.... I swaped my M40 318 engine for a M50 6pot when everyone else said it wouldnt be worth it! where abouts you based fella? can sort it out for you if you are near me. Quote Link to comment Share on other sites More sharing options...
carl0s Posted October 23, 2007 Author Share Posted October 23, 2007 ooh.. both of you, thanks for the feedback. I've been so busy I've been scanning the forum but not replying or reading much. The thing that concerns me, re: fan, is the leaking. If i get under the front of the car, the bottom of the rad is wet, and there's generally a bit of water on the car when we leave in the morning. Any ideas why the inside heaters would play up too? Engine type.. dunno! It's silvery looking, rather than black plastic, 4-cylinder, 1994 car. Amanda has gone to work in it so can't look at anything right now. I'm in Manchester. cheers Quote Link to comment Share on other sites More sharing options...
creative Posted October 23, 2007 Share Posted October 23, 2007 yeah I think thats the m40.... same rad as mine as well. The rads can go and usually crack around where the pipes connect. not often the heater matrix goes but they can become blocked but not very often. the reason for them not working will be air locks. If you do have a leak it can also draw air in at that point which causes the airlocks. I would be looking at the fan, stat and housing and the water pump. All diy'able and would take maybe an hour to do. The hardest part is bleeding the air out...sometimes takes 2 or 3 goes! as for the leak. Have a look around the pipes and make sure the clips are all tight. you should be able to spot a leak as it will be green where it leaks out. check the fins on the rad itself as these can pop as well, usually after overheating which causes extra pressure in the system and they fail if they are weak. £100 in parts would sort it all out, including the rad. oh and your only down the M62... im in wakefield if you want me to do it for you one night. Quote Link to comment Share on other sites More sharing options...
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