Cooling system problem

Red93BG · 07-11-2013, 12:36 PM

Hey guys,

First a little back story, bought the car (93 BG with the 1.8 DOHC BP engine) about 6 months ago for $150 with it barely running. Spent about $500 on her and shes almost like new except for the ruddy cooling system.

When i got her, there was no thermostat in there so i bought a Dayco replacement. I also flushed the rusty looking coolant and replaced it, and all seemed ok for a while. Then about 2 weeks ago the temp skyrocketed into the red and water was leaking from the timing covers so i changed the water pump. Ran the engine with the covers off and no more leaks so all looked good. Buttoned the rest up and went for a drive. Now it doesnt get critically hot but still above normal.

When driving, the temp gauge on the dash constantly fluctuates between the two lines in this drawing:

The bot line is the normal just below half and the upper is roughly 2/3 between H and C.

It seems that the main cooling fan comes on after the temperature gauge on the dash goes above the half way mark and cools it down a bit, sometimes all the way to normal sometimes not. The longer the car is run the more often the needle moves between the two. The other weird thing is that when the needle is above the normal position the car idles at about 1100-1200 instead of the usual ~700 like its trying to turn faster to cool it down?

The other thing i have noticed is that the condenser fan never comes on, even with the ac on full ball. I tested it with the car battery and the fan works just fine. Could this fan cause the problem?

Supposed to be driving it from sydney to brisbane on the 25th Nov so need to sort this out soonish, do you guys have any suggestions on what to try here?

Thanks, Reece

project.r.racing · 07-11-2013, 01:13 PM

no thermostat???

i had a car with a busted head gasket, that would overheat, so the thermostat was removed to keep the temps down.

got bubbles in the water under rad cap?

Red93BG · 07-11-2013, 02:06 PM

I did a compression test when i got it and all compression was equal and high so i dont think its the HG. And theres no bubbling with the rad cap off since i bled the system.

The thermostat is working properly too from what i can gather. The upper hose stays cold for the first few min of operation then gets hot very quick once the thermostat has opened i guess.

project.r.racing · 07-11-2013, 02:11 PM

not much a compression test will tell you head gasket wise when the engine is cold/cooler than running temps. things move and seperate with heat.

no bubbles after coolent change? weird the bubbles would just go away...

Red93BG · 07-11-2013, 02:22 PM

The compression test was done with the engine at operating temps.
There was no bubbles before the coolant change. Only for a very short time afterwards while the air was coming out of the system.

07-11-2013, 12:36 PM	#1
Red93BG Junior Member Join Date: Nov 2013 Location: Sydney Car: 1993 323 BG Astina Posts: 3	Cooling system problem Hey guys, First a little back story, bought the car (93 BG with the 1.8 DOHC BP engine) about 6 months ago for $150 with it barely running. Spent about $500 on her and shes almost like new except for the ruddy cooling system. When i got her, there was no thermostat in there so i bought a Dayco replacement. I also flushed the rusty looking coolant and replaced it, and all seemed ok for a while. Then about 2 weeks ago the temp skyrocketed into the red and water was leaking from the timing covers so i changed the water pump. Ran the engine with the covers off and no more leaks so all looked good. Buttoned the rest up and went for a drive. Now it doesnt get critically hot but still above normal. When driving, the temp gauge on the dash constantly fluctuates between the two lines in this drawing: The bot line is the normal just below half and the upper is roughly 2/3 between H and C. It seems that the main cooling fan comes on after the temperature gauge on the dash goes above the half way mark and cools it down a bit, sometimes all the way to normal sometimes not. The longer the car is run the more often the needle moves between the two. The other weird thing is that when the needle is above the normal position the car idles at about 1100-1200 instead of the usual ~700 like its trying to turn faster to cool it down? The other thing i have noticed is that the condenser fan never comes on, even with the ac on full ball. I tested it with the car battery and the fan works just fine. Could this fan cause the problem? Supposed to be driving it from sydney to brisbane on the 25th Nov so need to sort this out soonish, do you guys have any suggestions on what to try here? Thanks, Reece

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07-11-2013, 01:13 PM	#2
project.r.racing Senior Member Join Date: Sep 2004 Location: n/a Car: n/a Posts: 10,929	no thermostat??? i had a car with a busted head gasket, that would overheat, so the thermostat was removed to keep the temps down. got bubbles in the water under rad cap?

07-11-2013, 02:06 PM	#3
Red93BG Junior Member Join Date: Nov 2013 Location: Sydney Car: 1993 323 BG Astina Posts: 3	I did a compression test when i got it and all compression was equal and high so i dont think its the HG. And theres no bubbling with the rad cap off since i bled the system. The thermostat is working properly too from what i can gather. The upper hose stays cold for the first few min of operation then gets hot very quick once the thermostat has opened i guess.

07-11-2013, 02:11 PM	#4
project.r.racing Senior Member Join Date: Sep 2004 Location: n/a Car: n/a Posts: 10,929	not much a compression test will tell you head gasket wise when the engine is cold/cooler than running temps. things move and seperate with heat. no bubbles after coolent change? weird the bubbles would just go away...

07-11-2013, 02:22 PM	#5
Red93BG Junior Member Join Date: Nov 2013 Location: Sydney Car: 1993 323 BG Astina Posts: 3	The compression test was done with the engine at operating temps. There was no bubbles before the coolant change. Only for a very short time afterwards while the air was coming out of the system.