Getting Hot :( Help

[78mali350]

Okay so today i decided to take the malibu out on it's first real road trip. Granted it was only a forty five mintue trip it was a trip none the less. Anywho. When i am in town driving around i am normally just about 190 degrees. I can drive the car with a steady foot at 65mph and only run a temp of 210 degrees. The minuted i run the car up to seventy five the engine temp starts to climb and didn't stop really, of course i didn't try to make it to either. The car is pretty basic it used to be a 305 with the turbo 200 transmission and now it's a 350 with a turbo 350 transmission. So my question is why does it all of a sudden get hot on me? doesn't make sence to me.

What do i need to do?

Oh and the rediator was boiled out pressure tested and something else when we put in the motor so it is like brand new.

any help would be great

 

[smooth_358]

hows the clutch fan? How many row radiator

 

[Tony_SS]

Sounds to me like you a flow problem - dont take that personal 😉 190 around town is on the hot side too. Start throwing dollars at it - cheapest stuff first.

1. I would start by making sure that in fact your gauge is accurate. Is the sender coming from the head, like factory?

2. Replace the t-stat. It may not be opening to allow the coolant to cycle. I always us a 180 and drill 3 holes in it. Make sure its installed the right way. Run it, and make sure both hoses are getting hot and not collapsed.

3. Water pump may be failing and not pushing the coolant though. They are cheap enough to replace. Also check that your fan clutch isnt out - they'll make noise when the go.

4. Replace the radiator with a new 3 core brass, or an aluminum one from a 2000 z28 camaro.

That ought to fix it.

 

[R/T kota]

4. Replace the radiator with a new 3 core brass, or an aluminum one from a 2000 z28 camaro.

Will that fit with out any modification?

 

[Tony_SS]

4. Replace the radiator with a new 3 core brass, or an aluminum one from a 2000 z28 camaro.

Will that fit with out any modification?

It did in my old 84 Monte SS. I just had to slightly bend down of the trans cooler lines.

 

[85 Cutlass Brougham]

You can also use the aluminum radiator from a IROC Z. I have one, but have yet to put it in yet. I did verify that it fits by test-fitting it in a Regal at the junkyard I pulled it from.

 

[78MC-BBC]

you could also always remove the mechanical fan & clutch and replace them with the electric fans from a dodge intrepid, the cool my big block perfectly and is a common swap into g-bodies now.

 

[HFX]

You may be running too much timing from what you are saying. At 75 you should be getting plenty of airflow from the grills for the clutch not to matter. Other issues could be you aren't getting enough flow. Check your lower radiator hose for collapsing at higher RPM's when warm. If you keep it in 2nd and keep the engine RPM's the same, does the temperature climb also? Water flow can be from deposits in the block, thermostat that can't flow enough, improperly sized pulleys, or water pump issues (cavitation, impeller worn etc).

Make sure your air damn below the radiator is in place along with the diverters.

Electric fans will help free up horsepower on the strip. However, a 5 or even 7 blade clutch fan should keep your 350 happy. If you have a 2 core brass radiator it may not be quite big for 350. A 3 core though will keep almost any engine cool without issue even with the A/C on.

I just changed my clutch after I noticed the temp was very high when I went to adjust my new carb a bit the other day. It was up over 210 (and I have a 160 stat right now at an idle). It didn't change with engine RPM. Turned it off and it took about 5-6 seconds to stop. Put a new one in, stops in about < 2 seconds after the motor stops. Temperature is about 185ish with A/C running at idle. Bringing the car up to 1100-1500 rpm immediately drops the temperature down to 160. This is on a 307 with a 3 core, so you are a bit different. Going down the highway at 65 I'm getting around 175ish.

 

[Tony_SS]

Good points HFX, check the timing... I would find the root of cause before putting electric fans on it though.

 

[HFX]

I should mention, you need to check both the initial timing and the amount of advance on the timing.