Coolant Issue

[brandondan1]

Hey guys, I've been having problems with my coolant light coming on intermittently when the car reaches operating temp. Sometimes it'll come on, and sometimes it wont. My car also starts to heat up past the halfway mark when driving slowly or idling, quicker than it should.

I tried bleeding the system using the screw on the thermostat housing, but every time only coolant comes out. If I try to open the reservoir cap when the check light is on, i hear gushes of air, and by the time the cap is off the level is high again and the light goes off. Also, when I squeeze the hoses, I can hear 'swishing' like there's air in the system

Should I just drain the whole system and try to fill it up again? I've never had a problem like this before.

[jlevie]

A car that is running hot when idling with the A/C off can be suffering from a bad fan clutch, bad thermostat, or air in the cooling system. If it only happens when the A/C is on the aux fan may have failed. In this case my first suspicion would be the fan clutch, and you can easily test that. if it checks out okay replace the thermostat.

[brandondan1]

Thanks. Well, my fan clutch is good, I tried the newspaper method. I also replaced the thermostat a few months ago, but I guess it could still be faulty.

I think you're right about there being air in the coolant system, I just can't seem to get it out though. Gonna completely drain the system, refill and bleed and see if that gets me anywhere.

[rcko]

Dan, bleed the thing again. Let the cap of the reservoir (engine cold) and let thing idle and watch the fluid level. Then when hot open the thermostat housing screw and let that bleed also. Also dont forget the heatercore fluid by setting the temp switch to full hot and getting the water to circulate through it. If possible, maybe dont have to, but you can raise the front of the car a bit also to help the air bubble fwd and out.

Also Dan, we been having some pretty hot weather here. FOr refence mine been running a hair to the cold side of the middle and when idling like in a stop light it goes a bit past the middle towards the hot. IF idling for long with the ac on in this weather it will register about 3/4 of the way to hot but never past that

[dark89e30]

As a tech the next thing I'd do is a block test. This is a tube with special fluid that changes color if there are any HCs (from exhaust gas) in the coolant. It'll pretty much change color whenever there is a blown head gasket.

[thereisnoyun]

coolant temp sensor

check the coolant temp sensor. Because if you sensor is bad, it'll think the card isnt warmed up and it would either idle higher and heat up faster or the like. Coolant light? mine came on here and there, but it turns out my check panel was busted.

[brandondan1]

Thanks guys. I really hope it's not the head gasket. I replaced it just last year when I had what looked to be oil in the coolant. Ever since then there has been no visible mixing (oil in coolant/ coolant in oil).

I have a coolant temp sensor that should be coming tomorrow. The old one I took off snapped and the sensor was corroded as hell. My car would idle higher when cold than hot, but does that necessarily mean the sensor was functioning properly?

Would that sensor cause my car to misfire due to too much fuel being sent? I changed my coil/wires/plugs/cap/rotor/o2/exhaust/air and fuel filters out, as well as ran seafoam and CRC guaranteed pass, but there's still a slight misfire at idle, and the car is running rich.

I think my next steps would be CPS and AFM... starting to get a little pricey ><. I'll let you know how it goes!