I can't figure out why...........

[WRMZ71]

I can't figure out why my dang engine keeps on wanting to overheat. It's a 350 with a .488 .510 cam, edelbrock aluminum intake, holley 670 street avenger carb, and flowtech headers. It's got a recently new heater core, brand spanking new 4 core radiator and a 190 degree thermostat. That and I got an 16" electric fan along with the regular fan on the engine. I currently don't have a shrowd on it cause the one I had before would not work with the new 4 core radiator. I was thinking I had gases passing through a bad head gasket and pressurizing the coolant system but i checked it out and I didn't have any. I'm thinking water pump might be weak, but when you fire it up and look in the radiator the water goes down just like she ought to. Anybody got any suggestions? It just cannot handle sitting in traffic for nothing, and i'm talking like 5 min when its 50 degrees out and she's getting up to 240 already.

[bigvinnie]

So you've got an electric fan, and you've got it running constant and you're still overheating...?

How are the 2 fans arranged, electric as a pusher on the front and then the stocker as a puller...???

I don't see how the electric fan isn't able to cool things down, unless it's either not mounted right, or just not moving enough cfm.... how many cfm is the fan rated at and how do you have it mounted..???

Do you also have an a/c condensor and trans cooler in front of the radiator...???

[bpmcgee]

Are you running really lean?

Brian

[COBALT]

...and are you sure your thermostat is opening? You don't have it in backwards do you? I know it sounds dumb, but...

[Bill72BB]

The first thing I would do is try another thermostat ,I might even use a 180 .
The easiest thing to isolate . JMO

[jorgensensc]

With the hot summers coming, I would maybe run to a much cooler (165 degree) Thermostat.

[SCOTI]

Hell.... yank the thermostat & see if there's any change in operating temps (no cost @ all).

[WRMZ71]

I have tried pulling the thermostat but then it overheats driving down the road at sustained speeds. I'm more than likely going to go to a way cooler thermostat for the summer but still in 50 degree weather it shouldn't heat up like it does. As far as the electric fan goes I have one its a 16" i believe i can't exactly remember and I have it on the engine side of the radiator. It is pulling air in through and the stock fan is also pulling air. I don't have a tranny cooler or anything like that and it's a turbo 350 with a 2500 rpm stall.

[WRMZ71]

oh yea and as far as the mixture goes i always had to run premium otherwise the valves would rattle under heavy acceleration. I've just advanced my timing now cause i was thinking the mark on the balancer was off and now i can run the 87 octane just fine.

[71swb4x4]

I don't think a cooler thermostat will solve your problems. All they do is open at the temp, so it will just open earlier, but if you are running above 200 both the 190 and 165 will be open, so thta won't make it any cooler.

The electric fan could actually be in the way of the engine driven fan. It would be tough for the engine driven fan to pull extra air from around the electric fan. The way I always understood it was one or the other. In some cases you can use the electric as a pusher, on the outside of the radiator pushing the air in. It may be worth a try to pull the electric fan and see if that will help. If you can find a shroud that will work those help a lot too, forcing the fan to pull air through the radiator and not letting it grab air from the engine compartment.

Shawn

[zeeklu]

I had the same problem and it ended up being a bad gauge in the dash. try the sending unit also .I swapped gauges with a spare I had on the shelf. Chris

[SCOTI]

Originally posted by 71swb4x4
I don't think a cooler thermostat will solve your problems. All they do is open at the temp, so it will just open earlier, but if you are running above 200 both the 190 and 165 will be open, so thta won't make it any cooler.

The electric fan could actually be in the way of the engine driven fan. It would be tough for the engine driven fan to pull extra air from around the electric fan. The way I always understood it was one or the other. In some cases you can use the electric as a pusher, on the outside of the radiator pushing the air in. It may be worth a try to pull the electric fan and see if that will help. If you can find a shroud that will work those help a lot too, forcing the fan to pull air through the radiator and not letting it grab air from the engine compartment.

Shawn

I would agree..... one or the other. Or, a pusher electric on the condenser side of the radiator w/the mechanical fan & the correct shroud on the engine side.

[bigvinnie]

as long as the water pump is working and the thermostat is opening, the electric fan should be pulling enough air thru the core to keep it from overheating... I'd be curious about the fan's cfm rating... you want a fan that can at least pull 2200 cfm for a V8 with a 4 row core, preferably 2800 cfm...

Are you sure your temp gauge is not giving you a false reading..??? I had a stock temp gauge that started reading in the hot range and by process of elimination it turned out to be a faulty gauge.

[Low69CST]

I think you need to have one fan or the other as well. I've got dual 12's on my radiator. A single 16 may not pull enough air. Squeeze your upper radiator hose, make sure its gettin water through it and the thermostat is opening up good.

[WRMZ71]

gauge is good, i just replaced it. The last one i had overheated to 250 and then the gauge wouldn't go back all the way down, so I was driving around with the temp gauge reading like 230 all the time and then it would go up to 250. I was like Oh my god this things gonna burn up. Replaced the gauge and all is back to normal well with the gauge at least but it still runs hot. I got me a shroud to try in there so I might have to try what you guys are saying and take out the electric fan and try to fanaggle the shrowd in there and see what happens. Originally i was gonna put the fan on the outside of the radiator but i didn't want butterflies and all them moths and crap getting up in it and ruining my investment.

[Low69CST]

I would spin off the engine fan and see what happens. That would be easier than making a shroud. If engine tempature is more consistant but still hot, go to a bigger fan. You said you were thinking of putting it on the outside of the radiator, you do know you have to get a different fan for the inside or outside of a radiator right? Inside ones are pullers and are the most efficient, outside ones are called pushers. Do you have a pusher on the inside?????

[stepside71]

Is the water pump old ? The fins on the wheel can corrode away given time. The new thermostat may be defective. Is the water pump belt properly tightened ?

[WRMZ71]

The fan is a puller and i have it on the inside (engine side) of the radiator. The fan is actually interchangable to where you can flip the blade and make it a pusher. Is there some way to test a water pump cause thats what I originally thought it was?

[jhwkns]

Have you checked the bottom radiator hose to be certain that it isn't collapsing? The suction of the of the water pump will cause this. Is there a spring inside the hose? Good Luck

[WRMZ71]

Well pulled the electric fan, put on a shrowd that covers the hole fan and took her out for a spin cause i needed gas anyway. Everything was seeming alright was sitting right around 210 but then on the way home it started getting progressively hotter. around 250, noting I turned on the heater and it was blowing cold air. I drove some more then the temp started fluctuating then finally dropped back down to 210 and the heat was at the heater again. Pulled into the driveway and let it idle there while sitting in drive and once again it shot up to 250 fluctuated a bit and blew cold air. then put it in park and revved engine up to 2000 RPM and held it there and the temp fluctuated then went down to 210 again. It's gotta be the fricking water pump is what i'm guessing. Either that or the dang heater core is plugged but the one in there is about 1 yr old and I had the system flushed when i put in the 4 core and no crud came out. anybody know of a way to test the water pump besides putting a new one on?

[racedvl]

You could take the back plate off the water pump and inspect the internals.

[WRMZ71]

RaceDvl is it just like a fan that i check the blades on?

[Jeepster376]

Sounds like you may have a big air pocket in the cooling system. preventing circulation when the RPMs are low. Start with a cold engine and the radiator cap off, and top off the coolant as it's flowing then cap it when full.

[bigjimzlll]

check your timing...bet its retarded some

[Jeepster376]

Retarded timing can cause overheating, but if your getting fluctuations of temp and intermittent hot and cold air out of the heater, you've got a big ole air bubble in the system preventing circulation.