overheating.

[jrp928]

New to me 89 BG, 230k kms. Can do 20kms from cold, gauge behaves ok (just below centre, so thermostat seems ok), but on stopping there is coolant pissing out the reservoir overflow. Once or twice noticed fluctuations dependant on revs - idling, temp climbs a bit, raise revs, drops back. Also seen to climb on going up a hill. Plugs are completely clean (near new), runs very well, lots of power, revs freely, so dont think its a head gasket. I have been told the water pumps can suffer erosion of the rotor to the point it cavitates or doesnt do it job well, which might cause this problem? The way it blows frothy coolant out seems like trapped air in the system, so is there a way to thoroughly burp the system? Or do I have to dismantle all the little hoses and replace/clean them? Any idea what $ it will cost to do a water pump in Melbourne please?
TIA
jp

[Dogo]

maybe the fan isnt working?

[BigMal]

I would start by flushing the radiator and changing the thermostat. If not then it
maybe time for a new water pump but usually they leak when rooted. If you do
change the waterpump may as well replace the timimg belt while its all apart.

[jrp928]

Fan is working fine, cycles in and out ok. As for thermo, why would temp climb to normal and stabilize - indicates to me that thermo is opening at correct temp. If it was sticking shut, temp should misbehave more; if stuck, previously I have seen temp rise very quickly, and on siwtch off produce banging noises as pressure force it open and it clangs shut...no happening here. Anyway, its cheap enough to replace, but I doubt thats it. Coolant recently changed. My sons bg had a stuffed pump recently, and it was leaking...
thanks,
jp

[Rupewrecht]

Sounds a bit like a water pump. The ex-gfs Mirage had the vanes of the water pump completely erode away, and then once warm the temp would fluctuate and go waaay up on any sort of incline.

[boostedbatman]

This may seem like im reaching but this was enough to do all the above on my v6
My pressure cap on the overflow bottle
even when inspected it seemed fine but once changed as last resort the problems went away
The spring in the cap is designed to compress at a certain pressure, being that a cap is never thought of by the manufacturers as a part that should be built to last the spring will get a bit old and soft with age (just like the struts on your car). Also the rubber seal is cheap and nasty and they figure the spring only has to last as long as the seal so no need to spend big on development here. So we wear the brunt of it in the end
Check it out

[89sp1.8]

as of yesterday my car is overheating...i can strt it from cold and let it run and it will climb to normal temp and stay there.but if i drive it and then pull up at lights or stop the car, the heat rises very quickly.but if i take off and start to drive the air cools it down pretty quick.pretty sure fan still working...thinkin either thermostat is sticking,or possibly when driving for some reason fan stops workin..?any ideas?

[jrp928]

Going to change thermo asap, check for crap in there, hope I find something. pressure cap on BG is actually on the radiator, and its new. The cap on the overflow is passive here, just a cap with an inlet going to bottom of tank for suck back, and an overflow at top.
keep the ideas coming.
jp

[jrp928]

Changed the thermo, no change. radiator held 10psi for 15 minutes , no drop visible AT ALL, so dont think system is leaking as such. Unpredictable pressure....finally got temp to rise to 3/4 scale idling , after a run around the block, couple of hills. The radiator seems to be hot all over, so I dont think its blocked anywhere. one Curious symptom was a temp rise idling, that came down when a few revs were applied....sign of an eroded water pump impeller? Also doesnt seem to suck back all the overflow tank when it cools down....but cant see any leaks in the hose to reservoir, or in the pick up pipe?
jp 89 bg

[andrewgrazier]

Originally Posted by 89sp1.8

as of yesterday my car is overheating...i can strt it from cold and let it run and it will climb to normal temp and stay there.but if i drive it and then pull up at lights or stop the car, the heat rises very quickly.but if i take off and start to drive the air cools it down pretty quick.pretty sure fan still working...thinkin either thermostat is sticking,or possibly when driving for some reason fan stops workin..?any ideas?

yeah mines doing that too
it seems it always has, so i thoguht id get it fixed a while ago.
first the water pump was replaced because the old one i didnt think was working. then the radiator was replaced as well. it hhas a new thermostat in it too. the fan then wasnt working so ive replaced the fan with a different one from the standard one but it seems to be more powerful.

and it still overheats so ****ed if i know. im gonna take it somewhere soon n get someone else to look at it.
ive also tryed wiring on the fan so its always on
you can do that in the diagnostic box n its easy to do. al thoguh i could hear the fan always being on when the engine got up to temp