Over Heating

[johnm]

The water pump failed, that was the start. New pump thermostat all ok. for around 200 miles then overheating, drained and bled the system ok for around 60 miles - overheating again. Head off, gasket between cylinder and water leaking - head inspected no cracks. New gasket, thermostat. Head skimmed & new bolts, did several short trips no problem no water loss, car runninin well. Did 80 miles no problem, parked it all day did 8 miles gauge way up in the hot zone.
Home on a trailer, new radiator as after bleeding found it not warming all the way accross the top, idled for 30 mins no problem drove it 3 miles temp climbs.
Had a thought from other forums, possibly blockage in heater matrix causing intermitent cavitation of the hoses - followed by air lock and when that gets to the pump - no pumping- appreciate ideas or offers for one otherwise superb coupe!
Looking for the right madly frustrating smilie -

[97alpineM3]

I've actually seen that happen twice since I've been working on these motors.. the cause was:

The past owner induced the wrong type and make of coolant into the system durring the cars early years.. and ran it for many years to come.. thus causing a breakdown of the coolant... this happens when the silicates in the forumla begin to drop out too quickly thus foruming a gel like blockage... which over time.. will cause this problem... a blockage which then produces the cavitation.. and so forth.. so yes... this is most likely your problem.. as you have narrowed the problem down fairly well..

The solution on the other hand isnt all that great... on both of my past occurances.. the fault was found in the inlet ports of the block.. and inward... it also happend around the cooling lines of more than one cylinder.. causing the problem...

I hope your problem does not reach this far... and I hope you find a better answer...

Good Luck,

Les

[johnm]

Originally posted by johnm@Feb 1 2005, 01:25 PM
The water pump failed, that was the start. New pump thermostat all ok. for around 200 miles then overheating, drained and bled the system ok for around 60 miles - overheating again. Head off, gasket between cylinder and water leaking - head inspected no cracks. New gasket, thermostat. Head skimmed & new bolts, did several short trips no problem no water loss, car runninin well. Did 80 miles no problem, parked it all day did 8 miles gauge way up in the hot zone.
Home on a trailer, new radiator as after bleeding found it not warming all the way accross the top, idled for 30 mins no problem drove it 3 miles temp climbs.
Had a thought from other forums, possibly blockage in heater matrix causing intermitent cavitation of the hoses - followed by air lock and when that gets to the pump - no pumping- appreciate ideas or offers for one otherwise superb coupe!
Looking for the right madly frustrating smilie -

[snapback]284136[/snapback]

[johnm]

[quote=johnm,Feb 1 2005, 01:25 PM]
Sorry, new to the forum

Hi Les
Thanks for your reply. When the head was off we ran it through a cleaner as a precaution - but it did look clean before, no visble residue as we suspected a rad weld or similar may have been used previously.

We checked the solenoids int the heater area and they seem to work, tend to think these solenoids are go or no go and unlikely to be intermitent(?) also if these are intermitent can't see it causing a problem other than poor heating.


So next step is heater matrix removal and probable replacement.

Frustrating thing is I have had the car for 2 years done around 20k still only got 76k on the clock, and up till this have not spent at all apart from servicing.

thanks again

John