Loosing coolant after engine is shut down.

[Drago]

Prior history:

Changed out the upper radiator hoses a few months ago. Bled system per the Haynes manual and all was good. Changed out the lower hose last week, bled the system again and all was well until three days ago.

Current situation:

When the car is driven the coolant temp gauge moves in a normal manner (normal operating range on the gauge) but when I stop the car for more than a couple of minutes coolant spills out of the drain hose on the expansion tank. I'm loosing roughly a half gallon at a time. Temperature at the time of engine shut down is normal.

Any idea why this might be occurring? Water pump and thermostat were replaced with new units about 5K miles ago.

One other question....and I think this *might* be the reason for the expansion tank over flowing (feedback anyone?).....when you've finished bleeding the system do you wait until the engine has cooled down before topping of the expansion tank? That's what I've been doing (I have a serious aversion to opening a hot cooling system which stems from an incident while working on my old '72 Chevelle a number of years ago, the scars have finally healed, thanks very much) and I think that by letting it cool down I may be over filling the tank, leading to the blow off while parked. Do you guys pop the cap directly after bleeding the system and if so is the car running while you do this?

All replies are appreciated and thanks in advance.

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Marc
'86 944 NA

[eimkeith]

bad radiator cap...

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keith
'86 951 redNeckarsulm

[Drago]

A coworker of mine thought it might be a blown head gasket that's pushing air (exhaust) from the cylinder into the water jacket.

Any of you guys who've had a blown head gasket experience this sort of problem?

I really hope this is not the case.

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Marc
'86 944 NA

[Cebu]

85.5 944na..Had the problem of coolant dump after shutdown. Bled system again with heater at full hot and blower on high. problem solved.

[AFJuvat]

Sounds like a trapped air bubble (always bleed with the heater on). Check your cap and your thermostat.

AFJuvat

[Obin Robinson]

Originally posted by AFJuvat:
Sounds like a trapped air bubble (always bleed with the heater on). Check your cap and your thermostat.

AFJuvat

when my 924 was spitting out coolant, and my friend's 924 was spitting out coolant... it was an air bubble in the system in BOTH situations.

the BEST thing to do... honestly... seriously... is to pay $40 or so and have the coolant system flushed out. or, do it yourself for about $20 or so. it's the BEST thing i've ever done to my cars when they had coolant problems.

air bubble, bad radiator cap, and stuck thermostat are all possible causes though.

good luck!

obin

[Drago]

Thanks to all who've taken the time to post.

The coolant system was flushed when I bought the car some 5K miles ago (along with a new water pump and thermostat).

I checked the coolant level again last night before leaving work and it needed another half gallon or so. When I got home I immediately topped off the expansion tank and bled the system again (with the heater on full blast hot). There was initially nothing but coolant coming out the bleed screw. After a few moments this stopped and air was escaping. I finished bleeding and topped off the exp. tank to the minimum and parked it for the night. Drove it to work this morning with no problems.

I'll check it again when I leave work today, if I have to add another half gallon of coolant I fear that I may have a blown head gasket that's forcing air into the cooling system on the compression stroke (leak between the cylinder and water jacket). I'm also prepared to bleed the system in the parking lot if I have to.

Nothing like working on your Porsche in the employees parking lot.

Posted, I will keep you.

My car and it's coolant:

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Marc
'86 944 NA