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Thread: 96 328i Coolant leak at back of engine compt.

  1. #1
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    96 328i Coolant leak at back of engine compt.

    Hey,

    I have a 96 328I convertible and I have a nagging coolant leak that has gotten really bad. It hasn't overheated and there isn't any coolant smoke/steam in the exhaust. The car is parked until I resole this issue. I haven't torn into it yet. Any ideas?

    Thanks!

    Mitch

  2. #2
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    Fix it sooner than later, if the leak develops then you can overheat. Before pulling the manifold off get you hands on a coolant pressure tester, that way you can find the leak easily.
    Attn. NEWBIES: Use the search feature, 98% has already been discussed.
    Click the search button, select "search single content type", select the "e36 sub forum" specifically, try the "search titles" then try the "search entire posts".

  3. #3
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    Yea don't drive it tell you fix it

  4. #4
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    Probably one of the hoses that run from the head, firewall-side, to the heating valves (next to, below brake vacuum cylinder). Those are difficult to get to and are often 'forgotten' to be replaced.

    If you don't want your head or head gasket to blow, don't drive it anymore until you've repaired the leak.

    I've replaced most coolant hoses, but I still have to do the ones in the back (firewall side).. They are a pain to get to. Cable harness and intake manifold are in the way, unless you have baby's hands ;-) . As I don't use the cabin heater in this very mild climate, I'll probably end up blocking the coolant output from the head, but in any other climate I don't advise this. You can check the project here, along with some charts of how the coolant hoses run: https://www.bimmerforums.com/forum/s...t-2-Is-this-OK .

    Here's a pic of the coolant hoses.. Number 5 is probably the one that's leaking, but can also be any of the other hoses in the back (valve hoses are in another realoem chart):
    eliminatie_koelslangen.png
    Last edited by ed323i; 01-20-2019 at 03:15 PM.


    1997 E36 BMW 323i
    (European) 275k km (171k miles), with following small mods:

  5. #5
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    I say pull intake manifold to change the hoses .
    It is not that much more work and you wont struggle to change the hoses.
    And you can quickly do all of them .

    Sent from my SM-N950U using Tapatalk
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  6. #6
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    And check/replace all vacuum hoses while you're there. Perhaps also intake manifold gaskets, unless they still feel flexible and healthy.


    1997 E36 BMW 323i
    (European) 275k km (171k miles), with following small mods:

  7. #7
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    Thanks fellas! I'll probably pull the intake manifold this week and look.

  8. #8
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    Just my 2 cents, but i did not have to remove the intake mani when i replaced this hose, i think i loosened the engine wiring harness under the wiper cowl, and removed the cover that sits under it, i could reach the hose clamps and push the new hose on just fine.

    No hassle with intake mani gaskets

  9. #9
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    SimonJD, Thanks.. Good to know it can be done like that.. I'll give that a try soon, as I also need to do some work there. A lot easier than removing the intake manifold.


    1997 E36 BMW 323i
    (European) 275k km (171k miles), with following small mods:

  10. #10
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    Quote Originally Posted by SimonJD View Post
    Just my 2 cents, but i did not have to remove the intake mani when i replaced this hose, i think i loosened the engine wiring harness under the wiper cowl, and removed the cover that sits under it, i could reach the hose clamps and push the new hose on just fine.

    No hassle with intake mani gaskets
    This method should work fine. You should also have more than enough space if leak is coming from one of the hoses on the side of the head. Just remove the intake/throttle body worst case.

  11. #11
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    Good news!! I pulled the intake manifold and the throttle body and found a split in the hose coming out of the back of the head. I have ordered all new heater hoses and even flushed the heater core and the heater valve. lots of stuff came out. I may just order a new heater valve since the heater has not worked in a while.

  12. #12
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    Quote Originally Posted by sportbiker929 View Post
    Good news!! I pulled the intake manifold and the throttle body and found a split in the hose coming out of the back of the head. I have ordered all new heater hoses and even flushed the heater core and the heater valve. lots of stuff came out. I may just order a new heater valve since the heater has not worked in a while.
    Best to do them all - pulling the intake does make it easy to get them replaced

    Sent from my SM-N950U using Tapatalk
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  13. #13
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    With the intake manifold off, there are a couple of things you ought to do simply due to the vastly improved access. I've had to do most of these piecemeal over the years for various issues as they occurred. I didn't have the benefit of this list then.

    a. Clean icv. 5-10 minutes with carb cleaner. Free.
    b. Replace coolant temp sensor and air temp sensor. Sensors critical to the dme. $25 each oem.
    c. Clean all contact prongs on sensors with contact cleaner,. Use soft wire wool if corrosion is present. Clean connectors with contact cleaner and stiff toothbrush.
    c. Feed and return rubber fuel lines at the bottom right near the brake booster, and the two small ones at either end of the fuel rail. Inspect carefully and replace if suspect, and if they are abnormally hard. Use new clips if replacing them.
    d. Oil separator. Overhaul it. 15-30 minutes with carb cleaner.
    e. Ohm out crank and cam sensor and make sure they are in range.
    f. Check continuity of all sensor wires from the dme clamp. 20 year old wiring, might have breaks here and there. You will not know unless you check. You'll need a simple $10 digital multimeter, which is an essential tool for car maintenance anyway.
    g. Starter. Remove and inspect the carbon ring, replace carbon ring or starter entirely if you wish. Use penetrating oil if the bolts are difficult to remove. Not cheap - rebuilt oem starter $75-$100. Carbon ring $35.
    h. Alternator. Remove back plastic cover, remove voltage regulator if your engine has it, inspect the carbon brushes. Replace with oem regulator if they are so far gone you're going to lose charging in the next 2 months. If still ok but the brushes are short, order a new one and keep till the day you need to replace it. Or if you know how to solder, get two carbon brushes and solder them in. Get the ones with a slightly higher copper content - they last longer and still cost like $5 for a pair. And with the regulator out, inspect the alternator's copper slip ring. If it looks really worn, you need to plan for a rebuilt alternator at some point in the next 12 months. At least you'll have time to get something good but cheap.
    i. Look for evidence of oil and coolant leaks you're not already familiar with.
    j. Tighten all coolant lines. If the clips look suspect and might loosen out while driving, change them or put a little silicone next to the screw on the clip to prevent loosening. It can be easily removed if you have to loosen later. Do not use glue.
    j. Do a diy smoke test on the valve cover alone through the ccv port. And check intake air bellows for any cracks. Repair if possible, replace if not.
    k. Clean the head around the intake ports thoroughly with a rough cloth and brakleen.
    l. There is a small metal coolant fitting at the back of the engine. It is often very corroded. Look at it, and replace if suspect. Not expensive - $20-$30 with the gasket.
    m. If you are a glutton for punishment, remove all the injectors and backflush them at least. Or rebuild them by replacing their microfilters. Parts are very cheap. Consider doing this particularly if your idle is not totally stable.
    n. Take a long calm uninterrupted and unhurried 2 minute look in good light at every spot on the exposed engine for any signs of trouble. Then, if satisfied, reinstall the intake manifold.
    o. Before that, take closeup shots of your valves through the intake port. Take a picture of the exposed engine. These may prove very useful for you down the line. Email them to yourself right away to ensure they are not lost.

    Yes that's alot of work and will take you anything from half a day to one day to clear if you need to do all of them, and that's not even your issue here. Now imagine doing any one of them with the intake manifold still on. Will take 2-3 times the time and you'll probably put it off if you can....which means you'll have to do it sometime later when you have no choice.

    The name of the game with our cars, is preventative maintenance so that the car functions on our clock and not we on the car's clock. And it functions well.

    I see you have flushed your heater core area. Might as well flush the engine, and backflush the radiator.
    Last edited by Thomas525; 02-04-2019 at 08:09 AM.

  14. #14
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    Forgot one thing. Now's the best time to respray your intake manifold if it looks bad and can't be cleaned off. Use high temp spray paint with gasket lines and intake ports taped off. And only use matt colours, 1 good coat is enough but maximum 2 coats. And a coat of sprayed primer before the paint if not it will flake off too easily. Some blue-gray primer looks very good on its own.

  15. #15
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    I did not know the black plastic intake manifold was painted. I’ve drilled into it and cut it and scratched it over the years and never found a different color underneath.

  16. #16
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    No the black plastic intake manifold is not painted. It is manufactured with dyed thermoplastic. But of course, after that, it can be painted. That said, the matt black colour of the M52 manifold is very nice. However, after 20 years, it is likely to be scratched up, stained, and whatnot. If a good clean does not restore it to acceptable condition, then painting it is a very viable option. You will love how it looks - provided you only use matte paint.

  17. #17
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    Wow, Thanks Thomas. Great info. I have replaced most of the items besides the sensors. Starter, alternator, cooling sys, oil sep, all vacuum lines. Running evans waterless coolant. I really need to get the car back on the road

  18. #18
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    Main octopussian cooling system hose. wtf how did I forget that? That's one of the most important stuff to check and replace if the manifold is off. It only costs $50 oem.

    Evens coolant - that's seems a dilemma. Its fantastic that it runs with zero pressure and protects the metal and does not need changing. The thing that causes aged hoses and fittings to ruptures is pressure. However, when you need to change the radiator, or any major hoses, or the water pump or thermostat, you are going to lose the evans coolant and you need to topup with more evans. And evans is expensive. And if you have a leak or a rupture, you'll need to topup with water just to get home or survive for a time, and water ruins the evans and you have to flush and replace all the evans, which is costly.

    Evans coolant also has a lower specific heat capacity. It takes like half the heat of water to rise by the same one degree in temperature. I remember calling them about it some years go and the numbers they gave me was something like that. But I suppose that is not such a big deal, because that means it cools down to lower temperatures much faster in the radiator too.

    Reading about it here has piqued my interest though..

  19. #19
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    All I know is that my car runs fine with the evans and it isn't pressure cycling all the plastic cooling system components. If I have to do cooling sys maint., I drain and capture the evans and put it back in. All parts have arrived and I will start putting it back together tonight.

  20. #20
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    Please check the wiring to all the sensors and clean the connector and sensor contacts. Its so easy to do that with the manifold out. You must, 20 year old car.

  21. #21
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    Quote Originally Posted by Thomas525 View Post
    With the intake manifold off, there are a couple of things you ought to do simply due to the vastly improved access. I've had to do most of these piecemeal over the years for various issues as they occurred. I didn't have the benefit of this list then.

    a. Clean icv. 5-10 minutes with carb cleaner. Free.
    b. Replace coolant temp sensor and air temp sensor. Sensors critical to the dme. $25 each oem.
    c. Clean all contact prongs on sensors with contact cleaner,. Use soft wire wool if corrosion is present. Clean connectors with contact cleaner and stiff toothbrush.
    c. Feed and return rubber fuel lines at the bottom right near the brake booster, and the two small ones at either end of the fuel rail. Inspect carefully and replace if suspect, and if they are abnormally hard. Use new clips if replacing them.
    d. Oil separator. Overhaul it. 15-30 minutes with carb cleaner.
    e. Ohm out crank and cam sensor and make sure they are in range.
    f. Check continuity of all sensor wires from the dme clamp. 20 year old wiring, might have breaks here and there. You will not know unless you check. You'll need a simple $10 digital multimeter, which is an essential tool for car maintenance anyway.
    g. Starter. Remove and inspect the carbon ring, replace carbon ring or starter entirely if you wish. Use penetrating oil if the bolts are difficult to remove. Not cheap - rebuilt oem starter $75-$100. Carbon ring $35.
    h. Alternator. Remove back plastic cover, remove voltage regulator if your engine has it, inspect the carbon brushes. Replace with oem regulator if they are so far gone you're going to lose charging in the next 2 months. If still ok but the brushes are short, order a new one and keep till the day you need to replace it. Or if you know how to solder, get two carbon brushes and solder them in. Get the ones with a slightly higher copper content - they last longer and still cost like $5 for a pair. And with the regulator out, inspect the alternator's copper slip ring. If it looks really worn, you need to plan for a rebuilt alternator at some point in the next 12 months. At least you'll have time to get something good but cheap.
    i. Look for evidence of oil and coolant leaks you're not already familiar with.
    j. Tighten all coolant lines. If the clips look suspect and might loosen out while driving, change them or put a little silicone next to the screw on the clip to prevent loosening. It can be easily removed if you have to loosen later. Do not use glue.
    j. Do a diy smoke test on the valve cover alone through the ccv port. And check intake air bellows for any cracks. Repair if possible, replace if not.
    k. Clean the head around the intake ports thoroughly with a rough cloth and brakleen.
    l. There is a small metal coolant fitting at the back of the engine. It is often very corroded. Look at it, and replace if suspect. Not expensive - $20-$30 with the gasket.
    m. If you are a glutton for punishment, remove all the injectors and backflush them at least. Or rebuild them by replacing their microfilters. Parts are very cheap. Consider doing this particularly if your idle is not totally stable.
    n. Take a long calm uninterrupted and unhurried 2 minute look in good light at every spot on the exposed engine for any signs of trouble. Then, if satisfied, reinstall the intake manifold.
    o. Before that, take closeup shots of your valves through the intake port. Take a picture of the exposed engine. These may prove very useful for you down the line. Email them to yourself right away to ensure they are not lost.

    Yes that's alot of work and will take you anything from half a day to one day to clear if you need to do all of them, and that's not even your issue here. Now imagine doing any one of them with the intake manifold still on. Will take 2-3 times the time and you'll probably put it off if you can....which means you'll have to do it sometime later when you have no choice.

    The name of the game with our cars, is preventative maintenance so that the car functions on our clock and not we on the car's clock. And it functions well.

    I see you have flushed your heater core area. Might as well flush the engine, and backflush the radiator.
    Wish I had this list when I had the intake manifold out two months ago ! Thanks I saved it !

    Sent from my SM-N950U using Tapatalk
    This car is AWESOME !!!

  22. #22
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    Success! The car is back on the road. Now to fix the door locks. Thanks for the help!! Oh yeah, now the heater works, first time since I've owned the car.

  23. #23
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    Quote Originally Posted by sportbiker929 View Post
    Good news!! I pulled the intake manifold and the throttle body and found a split in the hose coming out of the back of the head. I have ordered all new heater hoses and even flushed the heater core and the heater valve. lots of stuff came out. I may just order a new heater valve since the heater has not worked in a while.
    Sportbiker, that's great that you got it all fixed up. In the course of this thread, SimonJD pointed out that the heater core hoses could be accessed without removing the intake manifold. Further, sportbiker mentioned that when he flushed the heater core, lots of crap came out. In another thread, we are having a member with issues related to a clogged heater core possibly. Flushing the heater core directly at least once every coolant refresh (every 2 years) seems like an intelligent idea.

    I guess what I'm driving at is, do you think there's a way to forward flush and backflush the heater core directly with a garden hose or something, without removing the intake manifold ? Since you just worked in that area, please think about it. If possible, lets create a simple way to do that conceptually and make that part of everyone's maintenance routine.

  24. #24
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    Quote Originally Posted by Thomas525 View Post
    Sportbiker, that's great that you got it all fixed up. In the course of this thread, SimonJD pointed out that the heater core hoses could be accessed without removing the intake manifold. Further, sportbiker mentioned that when he flushed the heater core, lots of crap came out. In another thread, we are having a member with issues related to a clogged heater core possibly. Flushing the heater core directly at least once every coolant refresh (every 2 years) seems like an intelligent idea.

    I guess what I'm driving at is, do you think there's a way to forward flush and backflush the heater core directly with a garden hose or something, without removing the intake manifold ? Since you just worked in that area, please think about it. If possible, lets create a simple way to do that conceptually and make that part of everyone's maintenance routine.
    Sure is. I watched a YouTube video a while back by Chris fix and got the idea from him. I bought poly tubing from Lowe’s and a clamp on male garden hose end. When I had the heater hoses off I connected the poly tube to the center heater core pipe on the firewall and turned the hose water on slowly. A whole bunch of crap came out. I let it run for a few minutes. Then after I put it all back together and took my time bleeding the cooling system, the heater blew HOT air for the first time. I’ve gone through several NorCal winters with no heat or defrost. Much better now.

  25. #25
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    Awesome! Chrisfix is a cool dude. You must be talking about this video :

    https://www.youtube.com/watch?v=LD2LGkUycQg

    Please confirm that this can be adapted to the E36 without first removing the intake manifold.

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