GO FISHING, use SLABSAUCE Fishing Attractant
Results 1 to 3 of 3

Thread: E34 535i overheating fix...

  1. #1
    Join Date
    Feb 2005
    Posts
    22

    Default E34 535i overheating fix...

    Reading the head gasket probs off the troubleshooting page...was EXACTLY what my 1990 e34 was doing...As advised, took car to pro shop and had tests carried out to determine if new gasket was required...Nothing wrong...Added new coolant, bled system and road tested...Same problem re-occured...gauge
    reading up to red, back to 3/4 mark and then back to centre...Plus, sitting at idle gauge backing up to red...

    Had ex bm dealership mechanic look and went straight away to radiator by-pass hose and expansion tank. With motor off blew airline gently down by-pass hose disconnected at both ends...cleaned hose at expansion tank end and blew hose line again, then reconnected hose. With cap off expansion tank, cleaned gunk out of coolant inlet hole, located just under expansion tank lip/cap position, with wire... Topped up coolant loss and with cap still off ran motor. Revved engine 'til coolant rose in expansion tank to just below overspill and could now clearly see coolant discharging from cleaned inlet hole into expansion tank. Checked rubber rings in cap were still flexible/supple. Ran motor for 60 seconds and system had self-bled out air. Replaced cap and checked gauge...Gauge returned to just under dead centre. (and has stayed ever since.. (7days). Car now idles fine in aussie summer temps too...

    Previously: in last 12-24 months have replaced entire cooling system components. Now each end of Spring, remove radiator and with air-line, gently blow off/out copius quantities of dead bugs behind grill/in front of auxillary fan area.. and fit new thermostat ready for summer weather....

    Footnote: Ex bm bloke explained 1/. As coolant wends it's way through rings in
    expansion cap to ensure they're not brittle/stiff/buggered etc...
    2/. To always check new expansion tank for coolant inlet hole being clean and clear as made by injection mould process, and inlet hole easy to miss for obstructions...Sure enough, mine had a tiny bit of plastic obstructing the inlet hole...

    Hope any of the above is of help...
    Cheers,
    Bayviewsbb

  2. #2
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,249

    Default good hint

    "To always check new expansion tank for coolant inlet hole being clean and clear as made by injection mould process, and inlet hole easy to miss for obstructions...Sure enough, mine had a tiny bit of plastic obstructing the inlet hole..."
    --------------------
    I got a new one 2 months ago. Just checked it when it was installed. Return od the coolant was a bit less than on the old one. But I did not check that further as cooling is o.k. But anyway, I will check that out now. Maybe it has not that much effect now, as we have winter here now compared to your summer in AUS.

  3. #3
    Join Date
    Mar 2005
    Location
    Long Beach, CA
    Posts
    2,563

    Default

    Quote Originally Posted by bayviewsbb
    Reading the head gasket probs off the troubleshooting page...was EXACTLY what my 1990 e34 was doing...As advised, took car to pro shop and had tests carried out to determine if new gasket was required...Nothing wrong...Added new coolant, bled system and road tested...Same problem re-occured...gauge
    reading up to red, back to 3/4 mark and then back to centre...Plus, sitting at idle gauge backing up to red...

    Had ex bm dealership mechanic look and went straight away to radiator by-pass hose and expansion tank. With motor off blew airline gently down by-pass hose disconnected at both ends...cleaned hose at expansion tank end and blew hose line again, then reconnected hose. With cap off expansion tank, cleaned gunk out of coolant inlet hole, located just under expansion tank lip/cap position, with wire... Topped up coolant loss and with cap still off ran motor. Revved engine 'til coolant rose in expansion tank to just below overspill and could now clearly see coolant discharging from cleaned inlet hole into expansion tank. Checked rubber rings in cap were still flexible/supple. Ran motor for 60 seconds and system had self-bled out air. Replaced cap and checked gauge...Gauge returned to just under dead centre. (and has stayed ever since.. (7days). Car now idles fine in aussie summer temps too...

    Previously: in last 12-24 months have replaced entire cooling system components. Now each end of Spring, remove radiator and with air-line, gently blow off/out copius quantities of dead bugs behind grill/in front of auxillary fan area.. and fit new thermostat ready for summer weather....

    Footnote: Ex bm bloke explained 1/. As coolant wends it's way through rings in
    expansion cap to ensure they're not brittle/stiff/buggered etc...
    2/. To always check new expansion tank for coolant inlet hole being clean and clear as made by injection mould process, and inlet hole easy to miss for obstructions...Sure enough, mine had a tiny bit of plastic obstructing the inlet hole...

    Hope any of the above is of help...
    Cheers,
    Bayviewsbb
    Good Catch by your mechanic.

    Ralph Mendoza Jr. - Long Beach, CA

Similar Threads

  1. Overheating :(
    By sal_park in forum 5 Series BMW
    Replies: 2
    Last Post: 09-24-2009, 02:31 PM
  2. Is your M50 overheating ?
    By shogun in forum 5 Series BMW
    Replies: 3
    Last Post: 06-13-2007, 01:13 AM
  3. e34 535i sudden overheating
    By Toomas in forum 5 Series BMW
    Replies: 11
    Last Post: 06-26-2006, 10:10 AM
  4. Overheating!
    By leetsauce4000 in forum 5 Series BMW
    Replies: 16
    Last Post: 10-31-2005, 08:51 PM
  5. 535i head gasket replaced...still overheating
    By bergie33 in forum 5 Series BMW
    Replies: 10
    Last Post: 09-23-2005, 07:49 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •