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Engine Temp Incresing

money pit

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I live in So. Calif. The temps are running in the high 90/100 degree range. I was driving on the freeway and noticed the temps were getting close to 250 degrees (AutoMeter gauge). I had to turn the heater on to cool the engine down to 190 degrees. I just had the radiator rodded out, new 180 thermostat, fan clutch is new, checked the timing, factory style fan shroud, and have fresh 50/50 mix of antifreeze. When I bought the 360 engine, I had it rebuilt. I didn't have the water pump pulley so I bought one on Ebay. The problem with this pulley was the belt hit the water pump housing, which I ground down. I ended up replacing both the water pump and crank pulleys because of alignment problems with the power steering pump. I purchased these pulleys from Vintage Air. They are supposed to be factory correct. The new water pump pulley is larger than my Ebay pulley, could this be the problem? The water pump belt drives the water pump, the A/C, and the alternator. Or, is the ambient air just too hot? Thanks.
 

Juan Veldez

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There is an additive for the coolant called "Water Wetter". I have heard a lot of positive comments about it knocking the temp down 10 degrees or so. It also allows you to go around 70 water/30 anti-freeze which in turn aids in better cooling also. This would be the cheapest and first try at fixing the problem, IMO. Then you need to dive into all those other items you mentioned that may not be working properly. When you say driving on freeways in so-cal, you mean mostly stopped? Does the problem occur while maintaining speeds above 50mph? If so, that can narrow down things to look at.
 

money pit

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There is an additive for the coolant called "Water Wetter". I have heard a lot of positive comments about it knocking the temp down 10 degrees or so. It also allows you to go around 70 water/30 anti-freeze which in turn aids in better cooling also. This would be the cheapest and first try at fixing the problem, IMO. Then you need to dive into all those other items you mentioned that may not be working properly. When you say driving on freeways in so-cal, you mean mostly stopped? Does the problem occur while maintaining speeds above 50mph? If so, that can narrow down things to look at.
I forgot to mention, I replaced the radiator cap (16 LBs). The temp increased on the freeway with a constant speed of 65 MPH. I'll try Water Wetter. Thanks.
 

Steve340

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250 is to hot. I would try the thermostat first - at least it is easy to replace.
 

money pit

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250 is to hot. I would try the thermostat first - at least it is easy to replace.
Thermostat is new. When I check the temp with a IR thermometer, the top hose and thermostat housing is about 245 and the lower hose is about 200. The temp gauge is located near the thermostat housing. Thanks
 

themechanic

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Sounds like you have the wrong pulley ratio. Water pump to crank pulley ratio was 1:1.
 

Juan Veldez

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Proper tension on the belt, not slipping? Just remember the fan itself is mostly to keep it cool at a stop light as 65mph wind going down the highway is fine without a fan, in most cases. That's why you normally hear an electric fan kick on when you come to a stop at a stop light, and clicks off when your up to speed. But you do need to turn the water pump! After the engine is hot for a while, turn if off and squeeze the top radiator hose. It should be solid and not collapse easy, indicating an air leak, unless it is really hot and coolant is escaping from the boil over hose. This isn't a 14:1 compression or twin turbo type of motor is it? Cause that bad boy would run hot when it's triple digits out!
 

Jm73340

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Thermostat is new. When I check the temp with a IR thermometer, the top hose and thermostat housing is about 245 and the lower hose is about 200. The temp gauge is located near the thermostat housing. Thanks
If the water entering the engine is in fact 200* your radiator is not cooling. Either not enough airflow or the radiator is shot.
 

money pit

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If the water entering the engine is in fact 200* your radiator is not cooling. Either not enough airflow or the radiator is shot.
The radiator was just rodded out. I have a 26 inch radiator in a 22 inch opening. Could that be the problem? I've seen postings that say it shouldn't matter. I have a six blade fan with a new fan clutch. Does a 7 blade fan move more air? Thanks
 

money pit

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Proper tension on the belt, not slipping? Just remember the fan itself is mostly to keep it cool at a stop light as 65mph wind going down the highway is fine without a fan, in most cases. That's why you normally hear an electric fan kick on when you come to a stop at a stop light, and clicks off when your up to speed. But you do need to turn the water pump! After the engine is hot for a while, turn if off and squeeze the top radiator hose. It should be solid and not collapse easy, indicating an air leak, unless it is really hot and coolant is escaping from the boil over hose. This isn't a 14:1 compression or twin turbo type of motor is it? Cause that bad boy would run hot when it's triple digits out!
The engine was rebuilt, stock, no modifications except a Performer intake. I have a 26 inch radiator that's in a 22 inch opening. The radiator was just rodded out. The hoses are firm, no leaks, new 16 lb. radiator cap. Thanks
 

Challenger RTA

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I forgot to mention, I replaced the radiator cap (16 LBs). The temp increased on the freeway with a constant speed of 65 MPH. I'll try Water Wetter. Thanks.
That sound like a stuck open thermostat.
A new thermostats can be bad. coolant won't stay in the radiator long enough to cool down.
 

money pit

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That sound like a stuck open thermostat.
A new thermostats can be bad. coolant won't stay in the radiator long enough to cool down.
I think I'm missing something. Don't you want the thermostat open when the engine is hot?
 

money pit

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No! only above the heat rating. Say it's rated 190 it will open somewhere around 200.
I see what you're saying. I have a 180 deg thermostat. the car runs normally around 210 deg. in the hot weather it's running close to 250. Thanks
 

Challenger RTA

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I would pull thermostat and test in hot water. I might be open when cold. you want no gap at all. no day light at all.
 
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Steve340

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With the engine getting that hot the thermostat may not be opening correctly - so it is a good idea to test it.
New is no guarantee it is working correctly unfortunately.
 

One of few

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Someone else had a similar heating/cooling issue, and if I remember right, he went to a 195 degree thermostat and his problems went away.
 
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