e46 coolant light coming on occaisionally.
Discussion
the coolant light on my 325 has started coming on intermittantly. usually for around 1 min then goes off again. the coolant levels are fine and i have been checking it daily since this has been happening.
the temp gauge itself sits steady in the middle and i dont have any other issues with excess heat.
dodgy sensor?
the temp gauge itself sits steady in the middle and i dont have any other issues with excess heat.
dodgy sensor?
It comes on as the engine is coming up to temperature? Mine did this and it was, indeed, a slow leak caused by a tiny split on the coolant reservoir neck. Seems once the car was up to temp, the light would then go out.
Strangely a pressure check didn't pick up on this at first and, fortunately for me, when it do let go (big style!) it was just as I'd pulled onto the driveway!
This year has seen the radiator, thermostat housing and said reservoir replaced.
Mine's a '53 plate e46 330i Sport auto saloon on 151k miles.
Strangely a pressure check didn't pick up on this at first and, fortunately for me, when it do let go (big style!) it was just as I'd pulled onto the driveway!
This year has seen the radiator, thermostat housing and said reservoir replaced.
Mine's a '53 plate e46 330i Sport auto saloon on 151k miles.
a1burns said:
My 330ci has started doing this again this week, last time it was low but haven't got round to checking yet...
Mines getting to nearly 75k so hoping I don't need to do a cooling system overhaul! Will check levels and for cracks tonight or at the weekend
It's not too expensive. £500 all in. You could end your engine with one overheat.Mines getting to nearly 75k so hoping I don't need to do a cooling system overhaul! Will check levels and for cracks tonight or at the weekend
pidsy said:
What do you get for your £500?
Can it be done on your driveway or is it really a garage job?
I checked my hoses last night and couldnt find any leaks.
On the E39: radiator, water pump, expansion tank, viscous coupling and hoses and labour. I get a garage to do it because I don't want to risk it going wrong. Can it be done on your driveway or is it really a garage job?
I checked my hoses last night and couldnt find any leaks.
Yup, I did the above work when the radiator needed replacing on my E46 330Ci. It was all relatively easy to swap it all out and with the youtube diy videos made it simple, driveway job for me.
I had to also get a new electric fan motor as the old one had given up the ghost (which I only noticed when I got stuck on the M4 in horrible stop-start traffic.)
Pidsy, are you getting any vibration in the car at certain speeds? That might cause the coolant sensor to come on/off?
I had to also get a new electric fan motor as the old one had given up the ghost (which I only noticed when I got stuck on the M4 in horrible stop-start traffic.)
Pidsy, are you getting any vibration in the car at certain speeds? That might cause the coolant sensor to come on/off?
Edited by roadmo on Monday 9th September 14:57
roadmo said:
Yup, I did the above work when the radiator needed replacing on my E46 330Ci. It was all relatively easy to swap it all out and with the youtube diy videos made it simple, driveway job for me.
I had to also get a new electric fan motor as the old one had given up the ghost (which I only noticed when I got stuck on the M4 in horrible stop-start traffic.)
Pidsy, are you getting any vibration in the car at certain speeds? That might cause the coolant sensor to come on/off?
no vibrations that i can feel at any speed. i have noticed that the light comes on when the engine is under heavy load i.e exceleration up to motorway speed, overtaking. it comes on for around 1 minute then goes off again. coolant itself is at normal level.I had to also get a new electric fan motor as the old one had given up the ghost (which I only noticed when I got stuck on the M4 in horrible stop-start traffic.)
Pidsy, are you getting any vibration in the car at certain speeds? That might cause the coolant sensor to come on/off?
Edited by roadmo on Monday 9th September 14:57
I've had this recently, coolant light comes on very briefly when the engine is cold, then vanishes again. Temperature is rock solid in the middle, car runs fine.
Only difference on mine is it's a 330d rather than one of the petrol models. I thought the cooling system on the diesels was a bit more robust?
Only difference on mine is it's a 330d rather than one of the petrol models. I thought the cooling system on the diesels was a bit more robust?
I had this on our 99 E46 328i. Changed the coolant level sensor and the overflow tank to no avail. Eventually spotted that when the engine was hot the upper rad hose swelled slightly. So I replaced it and all was fine. My theory is that after 150K miles the heat and pressure within the cooling system caused the aged hose to stretch just enough to cause the low coolant level to come on for a few minutes. It was quite predictable - drive 1.5 miles on B roads, wait at a roundabout, drive a mile or 2 on a 70mph dual carriageway and the light would come one for 30 seconds. Somehow related to the cooling system coming fully up to temperature.
phelix said:
I had this on our 99 E46 328i. Changed the coolant level sensor and the overflow tank to no avail. Eventually spotted that when the engine was hot the upper rad hose swelled slightly. So I replaced it and all was fine. My theory is that after 150K miles the heat and pressure within the cooling system caused the aged hose to stretch just enough to cause the low coolant level to come on for a few minutes. It was quite predictable - drive 1.5 miles on B roads, wait at a roundabout, drive a mile or 2 on a 70mph dual carriageway and the light would come one for 30 seconds. Somehow related to the cooling system coming fully up to temperature.
That is pretty spot on. I'll run it up to temp tomorrow then check the hoses again (It was cold last time I checked)Can you tell me where to get an e46 (328i auto) cooling overhaul done for £500?! (Or did you mean just parts??)
I priced up the parts and it came to £430 ish (rad, rad cap, rad hoses, water pump, expansion tank, fan clutch & fan clutch tool, thermostat, antifreeze). A local BMW specialist (Surrey) wanted £900.
I priced up the parts and it came to £430 ish (rad, rad cap, rad hoses, water pump, expansion tank, fan clutch & fan clutch tool, thermostat, antifreeze). A local BMW specialist (Surrey) wanted £900.
Edited by switch007 on Sunday 15th September 20:46
Edited by switch007 on Sunday 15th September 20:46
I have had so many coolant system issues on my E46 Manual trans 2000 323i (108K miles)
1st was a hairline crack in the reservoir fill bottle, the crack was on the left front radius corner looking down from the top (direction of crack was top to bottom) was about 3/4" long. This is a common problem, can only see it "weeping" when engine is hot and crack on the bottle is under pressure from boiling coolant, the bottle is supposedly HT PA66 GF. Hi temp Glass filled Nylon--(under designed imo)
I replaced it myself, some of the hose connection / reconnection were a bittch to remove and replace, suggest replacing all connecting hoses when changing reservoir bottle.
The bottle crack was a symptom of The fan motor not operating at idle--thus the system would get too hot if I did not drive it but left the car idle for 15 to 20 mins. mechanic replaced fan cost $280.00. angry at myself for not DIY on that one cause its easy to replace fan on the manual tranny e46 with parts on line at about $80
constantly chasing micro-leaks in the system, topping off coolant, replacing temp sensors, replaced thermocouple/thermostat, almost all coolant sensors on coolant lines and system,
IMO-the Coolant systems "suck" (poor design) on the e-46. seems I've read they start to show problems around 100K miles and then one problems leads to another--constantly chasing down micro-leaks. takes diligence, $, and patience--best of luck!
1st was a hairline crack in the reservoir fill bottle, the crack was on the left front radius corner looking down from the top (direction of crack was top to bottom) was about 3/4" long. This is a common problem, can only see it "weeping" when engine is hot and crack on the bottle is under pressure from boiling coolant, the bottle is supposedly HT PA66 GF. Hi temp Glass filled Nylon--(under designed imo)
I replaced it myself, some of the hose connection / reconnection were a bittch to remove and replace, suggest replacing all connecting hoses when changing reservoir bottle.
The bottle crack was a symptom of The fan motor not operating at idle--thus the system would get too hot if I did not drive it but left the car idle for 15 to 20 mins. mechanic replaced fan cost $280.00. angry at myself for not DIY on that one cause its easy to replace fan on the manual tranny e46 with parts on line at about $80
constantly chasing micro-leaks in the system, topping off coolant, replacing temp sensors, replaced thermocouple/thermostat, almost all coolant sensors on coolant lines and system,
IMO-the Coolant systems "suck" (poor design) on the e-46. seems I've read they start to show problems around 100K miles and then one problems leads to another--constantly chasing down micro-leaks. takes diligence, $, and patience--best of luck!
pidsy said:
the coolant light on my 325 has started coming on intermittantly. usually for around 1 min then goes off again. the coolant levels are fine and i have been checking it daily since this has been happening.
the temp gauge itself sits steady in the middle and i dont have any other issues with excess heat.
dodgy sensor?
the temp gauge itself sits steady in the middle and i dont have any other issues with excess heat.
dodgy sensor?
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