Coolant is leaking out from top of reservoir after driving

ALEXNICOLE

MEMBER
1995 HONDA CIVIC
166,300 MILES

This is a 1995 honda civic lx, everything under the hood is "stock" as in no mods only replace parts as they go out, and there is no a/c.

I was driving a few weeks back and felt like the car was "hot" but the gauge inside was only maybe 40%. I pulled over had nothing in the reservoir, filled it, let the car cool saw there was nothing in the radiator, so I filled that. Took it home, ran it with cardboard to find the leak didn't see anything. I replaced the radiator cap, and drove it around about 10-15 miles, and parked it with cardboard. I saw a green coolant leak coming around the oil pan and the muffler line(?) It was syrupy and only produced a 2-3 inch spot on the board.
Fast forward to today, its been sitting while I figure out my next move, drove it around the same distance as before and parked with cardboard. I noticed immediately a stream of coolant coming from under the car, popped the hood and saw it was coming from the top of the reservoir, it was totally overflowing. I have not checked the radiator again, because it was hot.

There is not any steam/smoke/liquid in tailpipe.

The radiator was replaced in 2010.

I had my oil changed 2k ago at honda, and only problem was rear brakes, which were replaced.

This car has not had mechanical problems since I got it in 2008, I don't even know where to go diagnostically from here, any and all help is appreciated.

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Wait for the engine to cool and then check the radiator coolant level. When it had run dry the other time, bleeding was not done so there could be air trapped in system. This would result in pressure in system thus the recovery tank overflowing. If the radiator coolant level is low, top up and start engine with radiator cap off for a few minutes. This would bleed the system and when the coolant level stabilises, close radiator cap. Run to operating temperature and ebnsure the cooling fans turn on and off before you stop engine. Wait for engine to coola and check radiator again.

Second thing is to check for leakages. Somewhere there is a leak as can be seen from the green stuff leaking around oil pan. You need to get under the vehicle to cjheck where it is coming from. Could be a bypass, heater, water pump pipe or even the water pump itself.