Coolant overflowing the bottle... no overheating... bad radiator cap?

[AcIdBuRn02ZTS]

Hey guys...

I picked up an '87 turbo 5spd car a few weeks back... pulled it out of a field with 135k on the odometer where it had been parked due to fuel pump failure. I just got the car road worthy today and put it through its paces..

Car stays nice and cool (just a tic below middle of the gauge)... no steaming from the exhaust or under the hood... no misfires... etc..etc..

When I parked the car, I noticed I had a trickle and I opened the hood and the intercooler was wet along with the overflow cap on the bottle had popped off.. bottle was full. The bottle may have been over full before taking it for a drive so I'm not sure if that could be the issue... or if perhaps the ancient radiator cap could be weak... I had driven it roughly 50 miles... some highway, some backroads, with a couple 2nd-3rd pulls.

No other symptoms... no other leaks. Heat works.. no gurgling... no milky oil.. coolant is clean... (which I flushed the coolant system and changed the oil in the process of getting it running.. both were clean). I'm not gaining any oil and I'm not getting any steam out of the exhaust... car runs strong... not popping the dipstick out of the tube or anything of the sort. No milk under the cap either...

So.. is this early symptoms of hg failure or could it be something as simple as an old radiator cap leaking? Should I go on and strip test the coolant just for giggles?

Thanks guys
-Chris

 

[hvyman]

make sure the cooling system is full. fill the overflow to the proper level. and then drive and see where its at.

 

[AcIdBuRn02ZTS]

Will do.. I'm going to go on and pick up a different cap in the morning as the one thats on it looks terrible. I suctioned the bottle down to the full mark and topped off the radiator...

It could very well still have air in the system as well from flushing it out... I filled the system from the heater hose until it flowed out of the cap... I had drained the block and everything... but I suppose its possible that it still has air in it since this was the first driving trip it has made.

Thanks for the advice... I'll post up tomorrow what comes of it.

On another note, the car had been sitting atleast 6 years.. its a bit on the rough side to say the least. lol

 

[MK3pizzadriver]

"Full" on the overflow bottle should actually read "hot". Don't forget the coolant expands as the car heats up, so yeah of course it's going to overflow out of the bottle if it's too full to begin with.

 

[supraguy@aol]

All in all, it does sound like a bad radiator cap could cause this issue.
Lets hope, at least.

 

[AcIdBuRn02ZTS]

Well..

I went down to the parts house and picked up a new cap.... suctioned the overflow bottle down to the "FULL" line and topped off the radiator.

I just got back from an hours drive... 20 minutes or so of 80mph interstate... some back roads... and several 2-4 wot pulls... got back home and let it idle for a bit.

First thing I noticed was it took a good bit longer to come up to opperating temp... not TOO long... just longer then it has since I got it running.

The electric aux. fan is kicking on at idle but the gauge is staying just a tic below middle. Hot heat as well.

So I shut it down and checked the overflow bottle.. it was about 3/4 full which is to be expected... no leaks or overfilling... lid was still in place. I'll check it in a couple hours to see if it pulled the coolant back into the radiator as it cools.. if not, I'll replace the hoses going to and inside the reservoir... but so far, all is looking good.

I'm glad because I'm really wanting to dip this thing this coming weekend... hg job was going to eat up those funds and push it back a week or so. Car is currently 5 different colors as the previous owner had a minor fender bender in it... and while it was sitting for 5+ years, his kids used the hood as a jungle gym... I had the parts laying around to get it straight... but it certainly looks funny. Now that I'm pretty sure its mechanically sound, I dont feel too bad about spending a little money to make it look decent.

-Chris