924Board.org

[d12-Matt]

In the Haynes manual it says the cooling system holds 2.11 gallons, but when I filled it up last time after flushing it, it only took about 1 gallon. After running the engine for a while, the water level is still full. Is this normal or do I have blockage somewhere that's preventing half of the water from draining out?

[wdb]

I dont know this car well,but it is a common problem with most cars that an air bubble trapped in the head prevents refilling the system.fill your overflow tank to the top and check it after a drive.when the engine heats up steam and pressure will drive the air out,then when the car cools,,a vacuum is formed in the cooling system,and the water in the overflow tank is drawn into the system ,but be carful if your system is very low ,driving should be short because of the danger of over heating. :maybe idleing in the driveway would be better,can keep a close eye on it.

[ This Message was edited by: wdb on 2002-01-10 11:09 ]

[d12-Matt]

I ran it for about 15 minutes just idling in the driveway. At first it seemed to be working alright; the temperature was about 1/2 on the gauge. But then I turned off the heater and it started slowly going up until it got to maybe 7/8 and that's when water starts dribbling out of the overflow valve thing and the engine has trouble idling by itself. So I shut the car off, let it cool down, and checked the water level again: it's still full though.

So far I have flushed the system with radiator flush chemicals twice and replaced the fan switch with a lower temperature one. The coolant still seems to have crud in it, so maybe I need to use a garden hose and spray full blast in there or something?

[wdb]

discribe crud,the water could be brown to orange from rust,black to gray from deteriorating rubber hoses,thick black sludge,if the P/O put stop leak in the radiator,creamy biege from oil in the water.have you been having a problem with over heating. To check if you have a leaking or blown head gasket,disconnect the coil wire(someone state if this is safe to do with this ignition system),remove the radiator cap,and look into the radiator,while someone else is turning the key,if your head gasket is leaking pressure or blown,the water in the radiator will rise and spill out of the radiator,evry time the piston nearest the leak in the head gasket,comes up on the compression stroke,because it is pushing air into the cooling sytem.If you think you have a bad head gasket,re torque the head bolts first and check it again.I assumed I had a bad head gasket,and didnt think much about the two loose head bolts,just to find the head gasket was fine,it was the two loose bolts that was letting the pressure from the cylinder into the cooling system.back to flushing,I have used a flush kit that came with an adaptor,that you splice into the heater hose and attach you garden hose to,and let it run for awhile.

[wdb]

there should be a hose,connected from just under the radiator cap,to the over flow bottle and it needs to be submerged in water,you should not be able to see water dribbling out of the overflow hose.if this hose has cracks or leaks in it,it wont hold the vacuum,and wont fill your radiator.the way it works is when you fill your radiator with cold water and put the cap on to seal the system. when your car heats up the water expands and takes up more volumn and spills into the over flow bottle,then when the car cools the water takes up less volumn and the water in the over flow is sucked back into the cooling system,to keep it full always.

[ This Message was edited by: wdb on 2002-01-10 13:18 ]

[Roger Hall]

Have you checked the thermostat. Ive have not worked on my cooling system, but I would check it out.

[d12-Matt]

When I first got the car it would overheat within a few minutes of turning it on. Now it seems to work fine as long as the car is moving. If I stop and idle the temperature goes up. The fan works fine though, it even continues to spin for a while after I turn off the car sometimes.

It was like dark grey or black flakes in the coolant. There used to be so much stuff in there that the first time I pulled the drain plug, nothing came out. It was just caked with that stuff.

I think the head gasket is good, because I did a compression test and all 4 cylinders showed like 140-150 PSI.

I took out the thermostat and boiled it in a pot of water and it opened up, so I think it works.

I'm not sure if I understand which overflow hose you are referring to. Here's a picture of the overflow tank:



I see water dribbling out of #1. Should there be a hose attached to that, or were you talking about #2?

[wdb]

see I was right when I said That I didnt know these cars well. I had to go look at my car,924 doesnt have a seperate overflow,I assumed they were just like american cars.that little red button behind #1 is the air trap,remove that red plug to let out the air,so you can fill it up. the black flakes are probably some kind of stop leak product,which might be difficult if not impossibe to get out completely.you might consider having your radiator cleaned by a pro,they take the end tanks off and push a rod through the water passeges,to get out the gunk,and reattach the tanks.(cost like $50) after you get your system cleaned out,watch for leaks,just in case the black stuff was a quick and easy way to fix a leak before selling the car , Sorry for the confusion,I need to do my homework.

[ This Message was edited by: wdb on 2002-01-10 17:22 ]

[d12-Matt]

I drained the system and refilled it twice today while testing the thermostat. Now it seems like the temperature stays less than 1/2 on the gauge even when I'm stopped and idling. However, idling at 2000 rpm makes the temperature slowly go up until it eventually overheats.

Could it be that my water pump isn't working well enough and pumping too slowly? My other thought is that the 1.8 ohm resistor for the radiator fan actually reads 2.2 ohms, so maybe the fan is spinning too slowly?

[wdb]

if your ignition timing is to far advanced it will cause you to overheat,so will vacuum leaks,and running lean,is your radiator grill full of bugs,mud and grime,restricting airflow.is your metering plate hanging up,if its not moving you will run lean at higher RPM's.is there a bad ground some where causing your o2 sensor or temp sensor to read incorrect voltages. change your thermostat. thats all I can think of

[Peter_in_AU]

you didn't say whether you opened up the bleed valve to bleed the air out of the system. Did you?

[d12-Matt]

I opened the bleeder valve but I don't think there was any air in the system (you could see water all the way up inside). But that reminds me, opening the bleeder valve when draining it let out a LOT more coolant. Last time I didn't do that, which I think explains why I was only able to add 1 gallon when refilling it before.

My radiator grill is nice and clean, and the water came out really clean today as well. Hey maybe it is the timing, because when I first got the car I fiddled with it but I'm not even sure if I set it properly. Thanks, I'll look into these things tomorrow.

[Peter_in_AU]

bleeding the cooling system is actually quite and involved process. Perhaps someone would reply with the procedure. I haven't had to do it on mine.

The Haynes outlines the process in the "cooling" section. I would suggest having a good read of the Haynes and giving it another go.