bayviewsbb
11-29-2005, 11:17 PM
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
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