My '95 Civic overheats. It has a new radiator, thermostat, and hoses (less than 2 years old). I checked the fan motor and it works. I checked the relay and it seems to work. The water pump seems to be working, but I'm unsure how to test it for sure. It gets hot and then loses coolant. At first it was losing coolant out of the overflow, but then I put a new radiator cap on it and now it seems to be exiting out the lower radiator hose @ the connection point???
What might be causing it to overheat?
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The idle also tends to fluctuate between 1000-1500± rpm. I read on another site that perhaps there is air in the cooling system that may cause it. Anyone have an idea or experience with this problem?
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Could my overheating and idle fluctuation be related some way?

Thanks.

 

You could have air in the system, or a blown head gasket. Try a leakdown test and see if you get bubbles in the coolant, or a coolant system pressure test to see if it holds pressure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drdisco69 &raquo;</TD></TR><TR><TD CLASS="quote">You could have air in the system, or a blown head gasket. Try a leakdown test and see if you get bubbles in the coolant, or a coolant system pressure test to see if it holds pressure.</TD></TR></TABLE>

 

how do you perform a leakdown test or a coolant pressure test.? im a noob i know

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtakvtrak &raquo;</TD></TR><TR><TD CLASS="quote">how do you perform a leakdown test or a coolant pressure test.? im a noob i know</TD></TR></TABLE>

coolant pressure test is done with a pump you connect to the radiator cap...you pump pressure into the cooling system and see if it holds on the gauge ...if it doesnt you have a leak....

leakdown test is done with a leak down gauge and an air compressor...

you have to set each cylinder at top dead center one at a time where the piston will be up and the valves closed... you then connect the gauge to the spark plug hole and pressurize the cylinder with a regulated 100 psi of compressed air..

the gauge will tell you what percentage of that 100 psi is being "leaked" out of the cylinder and you can listen or look for where the4 compressed air is getting out

headgasket you will see some bubbles in the radiator with the cap off

intake valves you will hear air leakign out of the throttle body

exhaust valves you will hear air leakign out of the muffler

piston rings you will head air from the crank case leakign out the oil dipstick hole or oil cap

 

Upon further inspection/troubleshooting I wonder if there is some blockage. I ran the engine for a good while and the fan didn't turn on until the engine was already hot (according to the temp. guage). Also, the 2 heater hoses at the firewall were somewhat warm, but nowhere near as hot as the other hoses.
Blockage?
In addition to that where is the air bleed bolt at? The Haynes book says it's on the thermostat housing, but I can't find it. It's in the picture, but I think the pictures in the book are of a '92 or '93 model, where mine, as previously stated, is a '95. I was going to bleed it, but...