Need some Experienced E30 advise

#1

So, at RA two weeks ago right before the start of the race Deb was taking the car out for HPDE session and before she got going the car dumped all the water on the grid. I had it towed back and took it home without seeing anything terribly obvious (Robert looked around as well, didn’t see anything). Well, I’ve been lazy and weather been great, so I didn’t touch it until today.

This morning - filled her back up with water, let it idle and get pretty nice and warm - not a drop anywhere. Took it for a spin around the neighborhood - nothing, not a drop anywhere.

So, for Jim Levie, Al, Robert, Travis, etc - what in the world can leak so bad 2 weeks ago and not so much as even make a drop today?

Needless to say, I’d hate to get to VIR and find out the problem is still there. Should I just replace everything? Thermostat, housing, water pump? All the hoses are pretty new and I imagine they would drip if there was a crack. Anyways, I’m at a bit of a loss here.

#2

Did you happen to see if the catch can was full? If it was, there is the possibility that you have a leaking head gasket. A diagnostic for this is:

Make sure that the system is fully bled, then drive the car for a while. Re-bleed and see if a significant amount of air is released. More than one drive/bleed cycle may be necessary for a proper diagnosis.

If not that, then suspects could be:

Loose hose clamp
Bad water pump seals
Failing radiator
Cracked reservoir

Most of those are solid failures, meaning that once the leak forms it will always be there. But a loose clamp or a bad water pump may only leak when the system pressure is high.

Bleed procedure:

  1. Using ramps or a jack get the front of the car 1’ or more higher than
    the rear. That will make the radiator and bleed screw the highest point
    on the engine and facilitate removal of air.

  2. With the bleed screw open, add coolant until no more air comes out of
    the bleed.

  3. Leave the filler cap off, or at least loose, and set the heat for max
    temp and fan speed. Leaving the cap loose will prevent air that’s still
    in the system from causing a “coolant fountain” once the engine heats
    up. Start the engine and allow it to warm up to operating temp. As it
    warms up occasionally crack the bleed screw to release any air and top
    up the coolant as necessary.

  4. Once the engine is at temp bring it up to 2000-2500 for a few seconds
    several times. Then crack the bleed until no more air is released. At
    this point the heater should be throwing lots of hot air, which
    indicates that the heater core is filled with coolant. You may have to
    repeat this a few times to get all the air out.

  5. Drive the car a bit, allow it to cool back down, and recheck the
    bleed for air. Over the next few days you may get very small amounts (a
    few bubbles) of air out of the bleed screw.

#3

My water pump went out on the way home that weekend. It was a slow leak over several hours of driving until I pulled into a gas station and then it dumped another gallon where I parked. After it cooled I filled it up. I was fine the next 2 hours home. If you have the mechanical fan installed grab it and see if you feel play. If your water pump is really bad it will move. Also if your alternator/fan belt feels looser than normal it is probably the pump. Having the belt to tight can damage the pump. That is probably what I did to mine.

If you still have the original heater core the plastic ends will probably pop. This should be obvious when your windshield fogs up.

#4

This is a little embarrassing to admit but I have over heated my car 3 or 4 times. With no mechanical fan, and a bad electrical fan resistor, this has happened to me if I forget to turn the fan on.

Each time I just refilled the system, bled it out and it has been “fine” There may be some issues, none that I have seen but I have no leaks or cooling issues and it seems the coolant and oil are staying away from each other. I first did this 4 years ago and the last time I did it was Road Atlanta in December…at night… Dont ask.
Each time the expansion tank has relieved the pressure through the pressure cap…or whatever that is called.

Anyway, take that for what it is worth, hope it helps.

Thanks,
Brian

#5

Check The catch can!!!

In April, I lost a radiator hose during a session, but I ran for almost 2 laps with the needle in the red. I replaced the hose and everything was fine for the rest of the day.

The Next day about half way thru the day my car started gradually over heating, but cutting the session short I was able to make it thur the day. each time the catch can would be full/overflowing.

Once I got home I Thought I found the source of the over heating (bad fan, thermostat and proper bleeding).
Ran the car in my driveway(30+ mins) and a few times around the block with no problems.

Next track day the first session is fine, the next session we get black flag all and I have sit in the pits idling. the temp started to creep up so I turned off the car. Black flag over and go back out, temp is still a little warm but figure some air would make it better. Temp did not get better, started getting worse after 2 laps and I pull in the paddock. Catch can Is full of water. let it cool and refill.

I make it about 3 laps in the next session and the temp is too high head to the paddock. Catchcan is full again and with oil in the water. I am Pretty sure my Headgasket is blown or worse.

the only thing I can think of is that the HG was failing before, but once the engine is mildly cool it is very hard to detect. Once the engine got Really Warm the HG couldn’t hold it anymore. The Head should be coming off this week, but with 100 degeee temps, I am in no hurry.

The theory: HG is letting combustion gasses in to the coolant

You can get test strips to see if exhaust gasses are getting in to the coolant

#6

Thanks guys - it seems all signs are pointing towards HG.

Jim - I’ll be bleeding the car although I have no heater core, but I’ll follow the other steps.

Dan - I checked the catch can and it’s only 1/4 full. I marked it and as I drove around and ran the car in the driveway the level did not go up. It just seems crazy that it would dump everything out idling on grid, but won’t even drip while being revved and run at home.

#7

That is not surprising. If it happens to be a head gasket problem, and if the leak is small, it will take while to pump up enough pressure in the cooling system to cause the cap to lift and vent coolant. At street speeds you may have to drive the car for 20-30 minutes to build up enough air in the cooling system to be detectable.

#8

Alex, you can be lucky like Jones or unlucky like Dan. it has happened to me both ways.

So you’ll not know until you know, and driving around on the street (ask me how I know) doesn’t usually tax the cooling system enough to show that the HG is going bad.

Now where is the problem that started the problem?. You need to find the leak.

Fred had one this past weekend at a crack in the overflow bottle.Stroup had a loss of coolant at a loop-hose that eliminated his heater core.

I’ve been stupid and left hose clamps not so tight.

RP