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turbojimmy
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Jul 22, 2014

454 Running Hot

So I just got back from my 2nd trip in my '84 Allegro. First trip was 300-miles RT in high-80 degree weather. Engine temps fluctuated but didn't enter the red zone until the last couple of mile from my house. I was trying to maintain a 45-MPH speed limit going up a long, steep hill. By the time I got to the top the needle was solidly in the red, but it recovered quickly once I crested the hill.

So the trip this past weekend was half the distance and it was 10-degrees cooler outside. I really wasn't too concerned with the temp until the last 20 miles of the trip. It seems to like lower speeds (50 MPH or less) better so I plan my routes accordingly. For this trip, I needed to get on an interstate highway for about 20 miles (65 MPH limit). The road leading up to the highway entrance was steep and long. By the time I merged onto the highway, the gauge was flirting with the red zone.

Thankfully the highway was fairly flat for a while and it cooled down a bit. Well, it wasn't long before I found myself climbing and climbing and climbing. By the time I got to my exit, it was in the red again. In my panicked state I thought I smelled antifreeze. Once I exited I pulled off into the shoulder. I checked the overflow and it wasn't boiling over. I let it idle for a bit with the clutch fan roaring. It cooled it down a little so I went on my way. At 35-40 MPH it cooled down almost immediately.

So it seems to not like highway speeds and hills. It recovers quick, but it's not really convenient to slow down to 40 MPH and drop a gear on a 65-MPH limit highway where everyone is moving at 80 MPH.

Looking at it, both the trans oil and the engine oil run through the radiator. I've gotten advice elsewhere that I should remove that hot oil from the radiator and install external coolers. It makes sense to me - opinions?

Also - would a cooler thermostat help? I have a stock-spec in it which is probably 190-210.

Last, there's no baffling in front of the radiator to direct air into it rather than around it. Should there be? There's a fan shroud and it's perfectly in tact. Clutch fan works, but it's not really relevant at highway speeds.

I have basically the same trip coming up in a couple of weeks and it's predicted to be a bit warmer ambient temp-wise. However, it doesn't really seem to be sensitive to ambient temps - it's the work it has to do that makes it hot.

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