E46 Fanatics Forum banner
  • Hey everyone! Enter your ride HERE to be a part of October's Ride of the Month Challenge!
1 - 20 of 46 Posts

·
Registered
Joined
·
135 Posts
Discussion Starter · #1 ·
okay. so a few days ago as i was driving to work i had my heater on. few moments later low coolant light came on. so i suspected a heater hose might be cracked and turned my heater off. the low coolant light turned off.
After i parked my car i made sure there was no water puddles or wet marks underneath. i came back to check for leaks a couple of hours later and huge puddle of fluid underneath. but i could see that there was 2 different colours green and blue. i knew blue was the coolant. green ??

so i inserted the key and turned on the ignition. low wiper fluid light came on. i went and checked the tank. it was drained to almost empty. i had filler it just a couple of days ago. i am not worried about that now. il look into that later.

so before i left work i topped off the coolant. i did not do a bleed because i suspected a cracked heater hose.

since then i am constantly loosing coolant everyday. just a little. so i top it off once every 3 days.

today though was weird. i topped it off yesterday and today morning while driving to work i had the temperature displayed on the dash ( thanks to the OBC functions ). i was keeping an eye on the temperature and it was holding steady at 98-99 deg C. and then all of a sudden it shot up to 120 deg C, i immediately pulled over and while i was about to stop the temperature came down to 82 deg C. and started to warm up to 98 deg C. i am guessing some air in the system might have caused the temperature fluctuation.

i park again on a dry spot come back to check after 3 hrs. i look underneath and i see coolant dripping slowly drop by drop right under the crankshaft pulley. ( thats the one at the very bottom. correct me if i am wrong).

Maintenance history :

after the ET blew up mid way i changed it along with the upper and lower radiator hose, i replaced the thermostat after i saw it was failing almost overheated my engine that time.

FYI :

i have tried to open the ET cap slowly to make sure the cooling system holds pressure ( by the hissing noise of the air rushing out) when the engine was cold. it holds pressure fine although i believe thats why the leak is becoming worse. stress on the weak point in the system.

the first time i bled the system with the leak present, i turned my heater on and it was fine. no low coolant light. ( this is when i was driving so could not check for leaks). came back home checked underneath the car and puddle of coolant underneath. almost all of the coolant in the heater core was gone and low coolant light came back on. refilled the coolant with heater off. have not turned the heater on since then.

there is no white goo in the radiator cap or the oil filler cap. no sweet smell in exhaust when engine cold or at operating temperature. so no blown head gasket.:woot:

the thing thats confusing me is that today i saw the coolant dripping from the front of the engine when it was parked up a slope. but the heater is at the back of the engine. am i missing something here. i dont want to open something thats not related to my problem and waste time. i have my finals coming up and need to study as well..

now back to the problem at hand. can anyone please tell me which components to i have to check for leaks and if any tips on how to check.
DIY please. i cannot afford to take it to a shop.

i am already spending money on coolant just to fill it up..

sorry for the long post.

TIA
 

·
Premium Member
2016 340i & 2002 325Ci
Joined
·
3,623 Posts
Check the water pump by removing the pulley, see if it's wet under the shaft/where it mounts to the timing chain cover. My leaked a few weeks ago, took removing the pulley to properly diagnose it. The Saleri pump is $37 at RMEuropean. Good luck.
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #3 ·
Check the water pump by removing the pulley, see if it's wet under the shaft/where it mounts to the timing chain cover. My leaked a few weeks ago, took removing the pulley to properly diagnose it. The Saleri pump is $37 at RMEuropean. Good luck.
thank you. will do that.
 

·
Registered
Joined
·
15 Posts
Get a flashlight and look down in between the intake manifold and the oil filter housing. You should see a bunch of rectangular shapes formed into the block. Are they wet or full of coolant? If so the problem is not the water pump or the thermostat... It would be the heater core (rigid plastic, probably brittle) pipe that comes out of near the front/top of the the head.

Sent from my LGLS992 using Tapatalk
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #6 ·
Get a flashlight and look down in between the intake manifold and the oil filter housing. You should see a bunch of rectangular shapes formed into the block. Are they wet or full of coolant? If so the problem is not the water pump or the thermostat... It would be the heater core (rigid plastic, probably brittle) pipe that comes out of near the front/top of the the head.

Sent from my LGLS992 using Tapatalk
i would not have thought about that. thank you.
 

·
Registered
Joined
·
6,473 Posts
i have tried to open the ET cap slowly to make sure the cooling system holds pressure ( by the hissing noise of the air rushing out) when the engine was cold. it holds pressure fine

th

TIA
With a cold engine, the system should NOT holds pressure. Where the built up pressure came from?
 

·
Premium Member
2016 340i & 2002 325Ci
Joined
·
3,623 Posts
With a cold engine, the system should NOT holds pressure. Where the built up pressure came from?
If I check my coolant in the morning, after sitting for 12+ hours, there's a slight hiss when I open the cap. This is normal.
 

·
Registered
Joined
·
6,473 Posts
" almost all of the coolant in the heater core was gone and low coolant light came back on."

How can you tell the coolant in heater core is gone?
You seemed to believe the heater system was leaking. Why?
 

·
Registered
Joined
·
15 Posts
This is a PSA.

It might not fix your problem today but its worth knowing.

Last year, I replaced the expansion tank, water pump, thermostat and all the easily accessible common hoses that everyone else does, I thought I had the system fixed. Until it was low again. The first time it was low was a few weeks later, I assumed I did not bleed it right... next time it is low I assume I must have done something wrong somewhere... Could not figure it out. FINALLY, after about 6 months, one day the low coolant light came on again, and this time it overheated instantly. I parked it immediately. It took forever to re-fill as it lost a lot of coolant rapidly. The heater core inlet pipe broke. No more tiny crack that NEVER was easily visible.

Even if you find your leak and are lucky enough that it is just a water pump or something, you need to address those rigid pipes under the manifold before you get stranded. Someday, it will happen. They are brittle.

Sent from my LGLS992 using Tapatalk
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #13 ·
With a cold engine, the system should NOT holds pressure. Where the built up pressure came from?
hmm..thats weird.. it actually does hold pressure just enough to make a hissing sound.. i have checked that with a couple of other e46 and found the same.
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #14 ·
" almost all of the coolant in the heater core was gone and low coolant light came back on."

How can you tell the coolant in heater core is gone?
You seemed to believe the heater system was leaking. Why?
thats because the first time i lost coolant was as soon as the heater was turned on. since then everytime i turn on the heater coolant leaks out like its peeing.

i havent used the heater since then. coolant leak is now reduced to dripping. i am guessing one of the heater hoses is leaking but i do not know how it can still leak when the heater is off...!!! :banghead:
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #15 ·
This is a PSA.

It might not fix your problem today but its worth knowing.

Last year, I replaced the expansion tank, water pump, thermostat and all the easily accessible common hoses that everyone else does, I thought I had the system fixed. Until it was low again. The first time it was low was a few weeks later, I assumed I did not bleed it right... next time it is low I assume I must have done something wrong somewhere... Could not figure it out. FINALLY, after about 6 months, one day the low coolant light came on again, and this time it overheated instantly. I parked it immediately. It took forever to re-fill as it lost a lot of coolant rapidly. The heater core inlet pipe broke. No more tiny crack that NEVER was easily visible.

Even if you find your leak and are lucky enough that it is just a water pump or something, you need to address those rigid pipes under the manifold before you get stranded. Someday, it will happen. They are brittle.

Sent from my LGLS992 using Tapatalk
i was thinking of replacing the heater hoses along with the thermostat gasket. i assume that could be a point of leak as well...
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #17 ·
how do i replace the heater hoses and how many are there ? i was watching some DIY videos and all of them were shot after the hoses had been removed. any help here is appreciated.
TIA
 

·
Registered
Joined
·
135 Posts
Discussion Starter · #18 · (Edited)
this is the cooling system parts catalogue i found at real oem for my VIN.

if i am correct the hoses i need to replace or check for leaks are hose numbers 5, 6 and 8 along with new o-rings.
 

Attachments

·
Registered
Joined
·
146 Posts
Have you thought to check your radiator for leaks? The sides of the radiator are pressed from the factory and will eventually give up over time. Fill the system run the car and look for the leaks on either side of the radiator. Its not always easy to spot due the ET and you may have to look from underneath. I know WP and thermostat are the first place to look and are cheap and easy fixes. Let's hope it's not the hard lines under the intake manifold. Good luck!
 
1 - 20 of 46 Posts
Top