vanishing coolant mystery

bryanthompson · bryanthompson's Garage

I've been losing a bit of coolant lately... I have to refill maybe a quart or so every two days, but there's no sign of where it might be going. I'm prepared to order oil cooler seals & take on the job, but there's no sign of either oil in coolant or coolant in oil.

It's been really cold here lately, so I haven't been able to really inspect for leaks. I just had the cooling system flushed twice in the last 3 months, new hoses and everything. It's possible that the clowns at the place I'll never go to again (yes, i'm bitter) missed a hose clamp, so that'll be the first thing I'm going to check.

But... if no coolant in oil, and no oil in coolant... then what?!

nynor · 01-03-2005, 09:14 AM

check spark plugs for steam cleaning.

IceShark · 01-03-2005, 09:44 AM

If you are losing a quart every two days so that you are now up to gallons of replacement fluid there should be some sign. Let the car idle when hot for a half hour and see if it is dripping on the ground. And look at the catch spots like that valley along the spark plugs to see signs of whatever color antifreeze you are losing. Probably should also check the heater core for leaking inside.

You are not going to miss gallons going into the oil (and oil usually leaks into coolant first due to the higher pressure) so the only other thing would be head gasket and it is going out the tailpipe. Look for white smoke.

bryanthompson · bryanthompson's Garage

Nynor - I just got back in from checking the plugs, and according to my haynes, they look alright. Just a tiny bit of black soot, but not much at all. I think that was from when it was burning rich because of a bad o2 sensor.

Ice - I'll let it warm up and idle for awhile. I've noticed that my thermostadt still works, becuase last night I had to pull over to de-ice my windows (21 deg outside and sleeting... it sucked) and the car did get to the middle mark and the fans kicked on. At this time of the year, going down the highway at 65, the temp gauge is always barely over the first (not farthest left, but the mark between straight up and all the way left... if that makes sense) Does that sound right?

Oil pressure going down the highway when not fully warmed up is just under 5 bars, after warmed up it's about 4. Then when idling and warm, it is between 2 and 3 bars. From what I've read that sounds normal.

Would my pressure be going nuts if I had a bad gasket somewhere? Or is it too subtle to notice?

IceShark · 01-03-2005, 10:29 AM

You have an early 944 so that temp mark sounds like the 80 C mark which is about right at speed in sub freezing weather. Oil pressure sounds good.

A bad head gasket can pressurize the coolant system, a LOT! You will squirt coolant down the overflow tube. Again you should see it.

Why did you have the cooling system flushed twice in the last 3 months? Since this has been done recently I would put a bad hose install, loose clamp, etc., high on the list and you are leaking somewhere you haven't spotted yet. If it is on the hot motor the coolant may evaporate and not show up on the ground so you need to search for the dried antifreeze dye.

bryanthompson · bryanthompson's Garage

The first time I had it changed, I did it because it had been a few years since the PO had it done. After the guys flushed it, there was a hose rubbing on a fan. I adjusted it as well as I could, then took it back to them. They replaced the hose and re-flushed.

I just got back from getting an estimate on my fresh dent, so I'm letting the car run for a little while to check for leaks. So far, nothing from heater core, and not much on the cardboard under the car. I'll let it go a little while longer and check again. I think what's on the cardboard right now is just from ice melting, but I want to let it go and make sure.

bryanthompson · bryanthompson's Garage

A ha! I just went back out there and looked at my cardboard. Lots of water from meltage, but I found probably 3 or 4 tablespoons of coolant coming from the water pump area. Sounds like water pump now... Much better than a head gasket, but still sucky.

So... Is there any way to tell if it'd be a water pump gasket or if it's the water pump itself?

Looking at my records... They did not replace the water pump when they did my belts/rollers 17,000 miles ago. Maybe it's time?

IceShark · 01-03-2005, 12:25 PM

Could be - watch it now you have a clue where it is coming from.

The hose that fits on the water pump to radiator can be a bugger where it goes over the exit port on the water pump. That could be on its last legs and chewed up. Water pumps only last about 40,000 miles though so it could be leaking out of the shaft bearings.