E36 Coolant Leak
Discussion
My incredible luck with cars appears to be continuing. The day I got the car back from the garage to fix a fuel leak, my 328i has now decided it wants to get through some coolant. The only issue is I am buggered if I can see where it's going. Now immediately (after 3 years with a Punto with a knackered HG) I started fearing the worst, however.
- No mayo in the oil cap.
- No oil in the water.
- Temperature is staying rock solid.
- Engine is running like a charm.
I noticed last night whilst fault-finding that I was getting no heat from the heater, so we bled the system and filled it up again, only to be greeted by a nice warm blast of air. I did about 20 miles in it last night with no issues, however I've gone to start it this morning only to be greeted with the infernal "Check Coolant Level" warning, which I did, and the coolant was around 3 inches below the cold mark.
So what the hell is going in? Is this because we bled the cooling system when it was hot?
- No mayo in the oil cap.
- No oil in the water.
- Temperature is staying rock solid.
- Engine is running like a charm.
I noticed last night whilst fault-finding that I was getting no heat from the heater, so we bled the system and filled it up again, only to be greeted by a nice warm blast of air. I did about 20 miles in it last night with no issues, however I've gone to start it this morning only to be greeted with the infernal "Check Coolant Level" warning, which I did, and the coolant was around 3 inches below the cold mark.
So what the hell is going in? Is this because we bled the cooling system when it was hot?
Top it up for now, and see what happens.
The coolant level senders are pretty dodgy too, they break pretty easy.
3 inches down in the side tank is only a cup full of water at the moment, so not a major problem yet, and have a look around the black thermostat housing, where the 2 rad pipes go for any white crystally deposits.
They can crack quite easily, and leak when hot, or just leak around the edges/pipe joins.
The coolant level senders are pretty dodgy too, they break pretty easy.
3 inches down in the side tank is only a cup full of water at the moment, so not a major problem yet, and have a look around the black thermostat housing, where the 2 rad pipes go for any white crystally deposits.
They can crack quite easily, and leak when hot, or just leak around the edges/pipe joins.
In my M5 - OK not the same but hang on - it was the water pump.
I attempted to change the thermostat, purely for a bit of man/car time and to make use of my tools at the beginning of the year.
Everytime I thought I had everything back together Id have a fairly substantial running leak upon startup.
Eventually I had it towed to a garage who diagnosed the waterpump. Coincidence I guess.
BMW have a weep hole on the front of the pump to denote its on its way out as the water finds its way through the bearings.
This weep cannot be seen from the top or bottom of the engine in my car and needed to be put on ramps and have decent inspection.
May be worth investigating.
I attempted to change the thermostat, purely for a bit of man/car time and to make use of my tools at the beginning of the year.
Everytime I thought I had everything back together Id have a fairly substantial running leak upon startup.
Eventually I had it towed to a garage who diagnosed the waterpump. Coincidence I guess.
BMW have a weep hole on the front of the pump to denote its on its way out as the water finds its way through the bearings.
This weep cannot be seen from the top or bottom of the engine in my car and needed to be put on ramps and have decent inspection.
May be worth investigating.
Also worth checking the lower sections of the radiator itself which are known to expand and split on the E36 when they get old.
(My 328i started using a small amount of water but I couldn't find a leak. Then one morning while on My way to work, I had steam coming out from the front grill!
. The temperature didn't rise though and luckily My local BMW dealership is half a mile up the road from work so I went straight there, where they found that the radiator had split around its base ).
Another issue is with the expansion tank on the side of the radiator which is also known to get brittle and split with age.
Both worth checking. Hope this information is of some help.
(My 328i started using a small amount of water but I couldn't find a leak. Then one morning while on My way to work, I had steam coming out from the front grill!
. The temperature didn't rise though and luckily My local BMW dealership is half a mile up the road from work so I went straight there, where they found that the radiator had split around its base ).Another issue is with the expansion tank on the side of the radiator which is also known to get brittle and split with age.
Both worth checking. Hope this information is of some help.
Thanks for your advice folks, I've got a few things to look at now if the problem persists. After work I checked the coolant and it was where it was this morning, so none leaked during the day. I topped it up (it took 500ml to get it up the the line) put the cap on and drove home. I've probably done about 90 miles in it since and have had no more warnings on the OBC. Big test will be after it cools down, but i'm hoping the coolant flush we did yesterday has cured the problem, and the low reading this morning was just it cooling down overnight. Fingers crossed!
I will probably fit the uprated water pump and thermostat housing at the end of the month even if there are no further problems as a matter of course.
I will probably fit the uprated water pump and thermostat housing at the end of the month even if there are no further problems as a matter of course.
OK bad news is it's still leaking. Good news is I think I know where its going. It appears to be leaking onto the cooling fan, and there are flicks of coolant all round it that weren't there yesterday. I can also hear what sounds like a water pump about to give up the ghost.
Anyone know where I can get one of the upgraded ones with either a metal or composite impeller?
Anyone know where I can get one of the upgraded ones with either a metal or composite impeller?
Sorry to hear that! 
It might be worth checking with BMW as they are not always expensive for everything. Otherwise http://www.c3bmw.co.uk as above or: http://www.gsfcarparts.com/ or http://www.eurocarparts.com/ecp/p/Car-Parts.
Be aware that the E36 can be an absolute pain in the a
se when it comes to bleeding the air out of the cooling system properly!, so if you bleed it and still seem to be losing coolant, it could quite easily just be trapped air in the system making it's way out.
(BMW had a right battle with mine for a day apparently and just when they thought they'd sorted it out, I picked up the car, put the key in the ignition and was greeted by a coolant level alarm!. Straight back in I go, "what the devil?" I enquire, "So sorry sir, it's been fighting us all day!, we'll take it straight back in fix it!". They said to keep an eye on the level for a couple of weeks and if there were any problems to bring it back in. It never did drop again though ).
Hope you manage to get it sorted!.
It might be worth checking with BMW as they are not always expensive for everything. Otherwise http://www.c3bmw.co.uk as above or: http://www.gsfcarparts.com/ or http://www.eurocarparts.com/ecp/p/Car-Parts.
Be aware that the E36 can be an absolute pain in the a
se when it comes to bleeding the air out of the cooling system properly!, so if you bleed it and still seem to be losing coolant, it could quite easily just be trapped air in the system making it's way out. (BMW had a right battle with mine for a day apparently and just when they thought they'd sorted it out, I picked up the car, put the key in the ignition and was greeted by a coolant level alarm!. Straight back in I go, "what the devil?" I enquire, "So sorry sir, it's been fighting us all day!, we'll take it straight back in fix it!". They said to keep an eye on the level for a couple of weeks and if there were any problems to bring it back in. It never did drop again though
). Hope you manage to get it sorted!.
Morning All,
My '28 has started behaving itself a bit better - i.e the rate of coolant loss has gone down quite majorly, however I can still see evidence of coolant being flicked round by the fan, so the car is sitting on my drive currently awaiting attention. It's still runs and drives fine, however the rattling noise when cold is getting worse, which makes me think the water pump is on its last legs.
My local BMW indie is picking it up tomorrow to invesitgate, however if it is the water pump it'll be 155 inc VAT. This is for the metal impeller version and full coolant change to BMW spec. I will report back when it is sorted.
My '28 has started behaving itself a bit better - i.e the rate of coolant loss has gone down quite majorly, however I can still see evidence of coolant being flicked round by the fan, so the car is sitting on my drive currently awaiting attention. It's still runs and drives fine, however the rattling noise when cold is getting worse, which makes me think the water pump is on its last legs.
My local BMW indie is picking it up tomorrow to invesitgate, however if it is the water pump it'll be 155 inc VAT. This is for the metal impeller version and full coolant change to BMW spec. I will report back when it is sorted.
Unlikely to be the water pump imo. My money is on (as mentioned above) the thermostat housing being cracked. There are four bolts that hold the thermostat onto the head of the block, check for cracks around the top right one (when standing infront of the car). They will be hairline, but thats all it takes when the system is pressurised.
Water pump is worth doing at the same time anyway though, god its a pain getting the clutch fan off . .
Water pump is worth doing at the same time anyway though, god its a pain getting the clutch fan off . .
bodhi said:
Morning All,
My '28 has started behaving itself a bit better - i.e the rate of coolant loss has gone down quite majorly, however I can still see evidence of coolant being flicked round by the fan, so the car is sitting on my drive currently awaiting attention. It's still runs and drives fine, however the rattling noise when cold is getting worse, which makes me think the water pump is on its last legs.
My local BMW indie is picking it up tomorrow to invesitgate, however if it is the water pump it'll be 155 inc VAT. This is for the metal impeller version and full coolant change to BMW spec. I will report back when it is sorted.
I had this once: I drove up the Alps, thrapped it all the way up and basically bent the temp needle round the max bit, and then let it cool down at the top.My '28 has started behaving itself a bit better - i.e the rate of coolant loss has gone down quite majorly, however I can still see evidence of coolant being flicked round by the fan, so the car is sitting on my drive currently awaiting attention. It's still runs and drives fine, however the rattling noise when cold is getting worse, which makes me think the water pump is on its last legs.
My local BMW indie is picking it up tomorrow to invesitgate, however if it is the water pump it'll be 155 inc VAT. This is for the metal impeller version and full coolant change to BMW spec. I will report back when it is sorted.
After a few days I noticed it'd dropped a bit of water, and was very low.
It drank heavily for a while until sorted itself out and I've never had a problem since. Very odd systems.
MickyLB said:
Unlikely to be the water pump imo. My money is on (as mentioned above) the thermostat housing being cracked. There are four bolts that hold the thermostat onto the head of the block, check for cracks around the top right one (when standing infront of the car). They will be hairline, but thats all it takes when the system is pressurised.
Water pump is worth doing at the same time anyway though, god its a pain getting the clutch fan off . .
Mine cracked in this exact position. I also had a total and utter PITA with air in the system. Took me 2 hours to bleed all the air out, i drove it left it overnight and them bam no coolant at all in the tank! filled it back up and its been dropping by an inch or so every few hundred miles!Water pump is worth doing at the same time anyway though, god its a pain getting the clutch fan off . .
FYI i did my thermo housing without removing the fan, its a bit fiddly and you need decent tools but its easier than taking the fan off etc!!
Is it an auto?
I had exactly the symptoms you describe on my E46 328 and the heat exchanger for the ATF fluid had failed. It is underneath the expansion tank on the E46, and uses the coolant to cool the ATF.
This was just after I'd had a new water pump on, and new coolant. Then, two months after it was fixed the expansion tank cracked too and threw all the new coolant away
Do it all together while you have the fan off
I had exactly the symptoms you describe on my E46 328 and the heat exchanger for the ATF fluid had failed. It is underneath the expansion tank on the E46, and uses the coolant to cool the ATF.
This was just after I'd had a new water pump on, and new coolant. Then, two months after it was fixed the expansion tank cracked too and threw all the new coolant away
Do it all together while you have the fan off
Edited by john_p on Monday 5th July 16:24
Nah it's a manual. I'll get the garage to have a look tomorrow, but given that they new about the plastic/metal impeller issue they seem to know their stuff, so we'll see.
In the meantime I have to slum it in my mum's E46 320Cd. Lovely car, but the steering is too light (on an O4 plate as well) and the engine is agricultural. I want meh 328i back....
In the meantime I have to slum it in my mum's E46 320Cd. Lovely car, but the steering is too light (on an O4 plate as well) and the engine is agricultural. I want meh 328i back....
Just had the garage on the phone. It was the water pump.......AND the radiator. 400 quid bill, get car back tomorrow. Yeowch.
Cue 2 weeks of answering the "What did you buy that old wreck for?" questions. I'd like to see what else I could have got for £1500 notes, and how much that would have been to fix....
Cue 2 weeks of answering the "What did you buy that old wreck for?" questions. I'd like to see what else I could have got for £1500 notes, and how much that would have been to fix....
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