My car seems to be overheating again. Why I have no idea anymore.

When I first got the car it ran fine, no overheating or any problems. After a few months I went to start it up again (had been working on the interior) it ran fine. I drove it around but it would overheat. So I flushed the coolant and replaced the fan and the thermostat.

Today was the first time I got to drive it around again. Drove it around for 10 minutes or so before it started to overheat. Pulled it into my driveway and my coolant reservoir was boiling. It was actually filled up to the top. I also noticed that neck where the thermostat is housed was leaking very very slightly. I didn't notice any other leaks anywhere. I know the coolant is circulating fine as I would run the car with the radiator cap off and I could see the coolant circulating. I think I am going to go get a 160 thermostat and replace the 180 I have in there. I will take a look at my water pump too to see if that might be a problem but I doubt it is if it's circulating the water.

Anyone have any other suggestions? Radiator is stock, I've replaced the radiator cap like a week ago. Fan is an aftermarket one and I have an air dam in place.

 

fans working good?

a 160 degree should be fine but it shouldnt get that hot with a 180. stock thermostat on my l98 i think was 195 and i didnt have cooling problems unless i sat in traffic on 90 degree days, as the fans came on at 225 degrees.

once i got a 170 degree stat and lowered the fan turn on temps, it ran COOOL.

i'd try the T stat and flush the radiator. also drill some holes in the T stat. drill 4 small diameter holes in the tstat ring, and that way coolant will flow alittle while the stat is closed and once it hits the temp its rated at, it will open up and get full flow.

Another option i'm not sure if its available is a waterpump overdrive pulley. get a smaller pulley and it should spin the pump faster to flush more water thru the system, thus cooling it off quicker

 

I checked just now and when it got up to operating temp I could hear a hissing coming from the water neck. Not sure if it's where the water neck meets the block or where the hose is. Tighting up the clamp on the hose didn't do anything.

I wonder if that might be a problem cause then wouldn't it not get up to the correct pressure and thus boil at a much lower temp?

 

MavViper, unless I missed it, you did not mention your coolant fan switch. You need to check and see if it is working. A lot of people post about over-heating cars and find that the wire that attaches to the switch is burned, gone or not attached. Look on the passenger side of the engine between #6 & #8 cylinder for the switch, it is easier to see from under the car. You want your thermostat and fan switch to work together so check the switch first. Do you have single or dual fans?

 

single fan but I have it wired up so that the fan comes on when I turn on the ignition. Ya it will burn out the motor on the fan sooner but keeps my engine cooler (supposedly).

 

Did you use sealant on the thermostat housing when you installed it? Did you torque the bolts(25#)? When is the last time you flushed the radiator? If it sat for awhile, it could be full of all sorts of nasty stuff.

 

Definitely solve the hissing. Without proper pressurization, coolant will boil
much quicker -- obviously not a good situation.

And just because you see coolant flow at the top of the radiator, doesn't
mean you have adequate flow through the entire core. And if the system
wasn't adequately maintained prior to the extended shutdow, sediment
collection sounds very likely. A good flush (the stronger 2-component
stuff) & fresh A-freeze is the cheapest, most effective PM for your
cooling system.

Good luck,
kk