Help me with my temperature situation

[Car #4]

I have a 440 with Edelbrock top end kit. 26” three core aluminum rad with shroud, no electric fans. Temp gauge is OER, the numbers I give you are best guess according to the gauge. From cold start I run easy and temp goes up to about 180 and holds. I punched it hard once this evening for about 1/4 mile and temp goes to about 195. If I do that a few times temp will go to 115-120. But every time the temperature goes up it will hold at that level. It seems the cooling system can maintain a temperature but not reduce it. What are your thoughts? Thanks

 

[khryslerkid]

Do you have a spring in your lower radiator hose to keep it from collapsing?

 

[Don Frelier]

How far is the fan into the shroud?

 

[snakeoil24]

Fan needs to be 2/3 in shroud with no more than1/4 from blade edge to inner diameter of shroud and have you checked if clutch fan is shot?

 

[PurpleBeeper]

In general, your cooling system "can't quite keep up". I think we need to know, "When it gets hot and stays there, are you continuing to drive at highway speed, or are you cruising around town stop & go?"

Here's my thinking. You need 1. Overall cooling capacity 2. Air flow 3. Coolant that transfers heat well 4. Coolant flow

1. Capacity --> It sounds like your radiator should be plenty big enough & a shroud is a good thing. I think you're good on that assuming that radiator is all plugged up with crap (is it?)

2. Air Flow --> A good point made by Don. Is your mechanical fan sticking into the shroud and pretty close to the radiator (good) or sitting way at the back side of the shroud (bad for air flow)? There's some optimal distance fan/radiator/shroud which I'm sure you can search for here. Also, is that fan clutch working? Does it lock up & spin fast when the engine heats up or does it keep on spinning at half-assed speed? Is the radiator clean (good) (& A/C condenser if you have it) or is it full of dirt/leaves (bad)? Is there a pretty much un-obstructed air flow path into & through the radiator? (e.g. no turbo intercooler, no oil cooler, no trans cooler, etc blocking radiator)

3. Coolant Heat Transfer - You're not by any chance running that Evans (no water) coolant are you? It doesn't transfer heat well. Have you checked the strength of your coolant (those little float things) to see if it's close to 50/50? Side note - I had a car once that was overheating...finally realized I have put "coolant concentrate" (bad) (the straight stuff) and not 50/50 antifreeze (good). Lastly, Is your radiator full? Have you replaced the radiator cap? (good cap with correct pressure cools better)

4. Is the water pump working? Is the belt tight? If the pump is really old and/or you've not really changed your coolant often? "Sometimes" the water impeller on the inside of the water pump can rust away from years of crappy coolant in the system. It's rare, but does happen.

How far is the fan into the shroud?

Good calls, both Don & Kid....good calls.

 

[hunt2elk]

Wouldn't hurt to buy a cheap infrared temp gun just to verify your oem gauge as well.

 

[diesel_lv]

General reference on measurements. As for the 3 row aluminum radiator, how many rows is irrelevant if the rows are not big enough each and the fins per inch and spacing of the rows are not correct. I only use 2 row aluminum that are 1" to 1.25" per row. These are capable of cooling 496" 610hp engine in 125° AZ summer temps.

 

[Car #4]

Easy reply first…I did temp gun it after I got home. Readings seemed about what I would expect. Was actually surprised how hot the coil was. Didn’t know that.

 

[Car #4]

Do you have a spring in your lower radiator hose to keep it from collapsing?

I can squeeze hose tight so I guess not. I think I have a couple. I’ll put one in just to be sure.

 

[Car #4]

How far is the fan into the shroud?

About 2/3 in the shroud. 1.5” between blade and shroud.

 

[Car #4]

PurpleBeeper,
1. “when it gets hot and stays there I continue to cruise at highway speed.
2. On the point of air flow, I have Classic air conditioning and the condenser is nearly as big as the rad which will definitely reduce airflow through the rad. I was not running A/C and when I have I’ve shut it off if the temp get too warm which has helped.
3. I believe it’s 50/50. Here’s the thing, the car had no overflow bottle (68 Charger). I would have coolant half full in top rad tank. Go for a run and after it cooled down I could not see coolant so I figured it pissed it out the overflow hose. I recently put a 2x15 bottle on. I know the coolant has gone into it because it’s wet inside. But once again I can’t see any in the rad.
4. I bought car rebuilt. It has about 2500 miles since then. I have to believe the water pump is good but I have not seen it off the motor.

 

[diesel_lv]

Radiator level on these should be 1" below bottom of Radiator opening. Drive it to operating temp, then shut off and let cool completely. Then check after completely cooled off and top off if necessary. After that, it should maintain the level without puking. Have you rented a pressure tester for radiator n cap. Test both. A bad cap or very slow leak at a hose connection will cause it to have those symptoms too.

 

[Geoff 2]

Do you have a corrugated upper rad hose?

 

[Car #4]

Do you have a corrugated upper rad hose?

No.

 

[451Mopar]

I had an issue sort of like that, but worse. Driving easy, 55 MPH engine did not overheat. If I drove hard, or 70 MPH, the car would overheat, and the temp would just keep climbing even after slowing down. Would have to pull over, shut off engine and let engine cool way down before it would cool correctly again. I think it had a bad head gasket that allowed cylinder pressure to get into the cooling system and then the system would air-lock blocking normal coolant flow. This was an original 440 with steel shim head gaskets.
My car was also a 4-speed manual, so no trans cooler in the radiator.
With automatic trans, I run the trans output line to an external cooler than from cooler to radiator, and then back to trans return line in rear of trans.

 

[R413]

I had a similar problem. Turned out the carb was lean, different carb and coolant temps we’re then perfect. Car ran great and didn’t have lean surge or anything.

I first focused on cooling system and swapped changed a lot of parts with no help. Fans, pumps, t-stat, radiator, additives, etc.

 

[Car #4]

I would say if anything I'm running rich. Don't know how that might affect things.

 

[Don Frelier]

The first thing would be to keep the radiator core covered with liquid.
If you keep needing to add fluid and it's below the core everytime you check it then you are losing it somewhere.
If there is not a noticeable leak or coolant smell you almost assuredly have a head gasket or head leak.

 

[66Satellite47]

Car#4, if you are losing coolant, it is going somewhere. Either the cap is bad and it's going out the overflow or maybe a head gasket. If the level in in the rad starts dropping below the top tubes, it gets hot.

 

[Don Frelier]

Good point try a new cap first.