95 brave 454 running hot on long hills

craigspeer2001 wrote:
I never really here the fan come on and the electric fans works when you run the ac i got a new clutch and water pump so will find out tonight our tomorrow morning and ill post results.

You will absolutely with out a doubt hear the fan if the clutch engages. If you do not hear it, it did not engage.

Born To Travel wrote:
The AC does not control the electric fan.. The ECM does when it senses the engine heat is above the set temp...

No but yes. The ECM knows when the AC is turned on, and automatically turns the electric fan on. It can turn the fan on for other reasons, but the ECM is programed to directly turn the fan on, when the AC is on. Otherwise when the coach is sitting still, the AC would not cool very well.

As far as the coach running hot, sensors are notoriously inaccurate. Reading directly off the ECM should give you a much more accurate reading than the gauge temp sensor. You may want to check your timing. I know it is a set it once and forget it type thing, but the first person who set it, may not have set it right. You could also fudge the timing in 2 degree increments. You can listen for knock, but it will be a little difficult to hear, as when the ECM hears it, it will retard the timing. Its best to play with timing when you can read the knock count from the ECM. This would allow you to set it right on the edge. If you blindly want to bump the timing, try it and see if there is a performance difference. If the performance does not slightly improve, then don't adjust any farther, because you are probably up against the knock sensor.

If your not hearing the clutch fan kicking in, it's probably not working. The other thing to look for is to make sure the rubber "dam" is in place above the radiator. So the air goes through the radiator instead of over the top of it. one thing that I did was to seal up any area behind the grill where the air could bypass instead of going through the radiator. The electric fans on mine are controled by the trinary switch on the air conditioning line. But I put an over ride switch on them also to turn them on when ever I want. But of course the best thing to do is a recore/new radiator but you've done that already.

The AC does not control the electric fan.. The ECM does when it senses the engine heat is above the set temp...

I never really here the fan come on and the electric fans works when you run the ac i got a new clutch and water pump so will find out tonight our tomorrow morning and ill post results.

If you suspect the fan clutch may have a problem it is pretty easy to check.

My last coach was a 1995 P30 with a 454 and the service manual had a procedure for checking the fan clutch. They said to measure the temp of the AIR coming out of the radiator. I used a metal meat thermometer. I had to drill a small hole in the plastic shroud around the fan so I could get the thermometer between the fan and the radiator.
They said to block the radiator with cardboard and run the engine at about 2000 RPM to get the engine to heat up.
The fan will spin before it's fully engaged, but it's obvious when it engages because of the noise.
It should engage at an air temp between 165'F and 195'F. If it doesn't it should be replaced.

my 94/5 bounder on a p-30/32 chassis used to run hot. I added an additional cooling fan which helped.
bumpy.

How hot is hot to you? Does the fan clutch kick in before the red area if you have the Chevy OEM gauge? Will the temp come back to normal once you climbed the hill and start descending fairly quickly(3-5 mins)?

I have a 1994 454 and I just came back from Oregon and pulled some pretty good hills there and other places.. I would turn off the AC pump starting up those hills and the worst it got was about 200 degrees on one very long pull... Do you have an electric fan in front of the condenser and is it working ok?. I also have ceramic coated headers and they seem to help too... Also a good mechanical temp gauge...

years ago had a 454 , it ran hot headers helped a lot.

ON my 454 on long pulls it would heat up.....like you, hotter than I wanted ....but not boiling.....First I installed a SW mechanical temp gauge so I knew exactly what the temp was....and then fabed a radiator spray system for exactly that problem....When on a long pull the last thing I want to do is stop uphill to cool off. When I sprayed it,it would drop the temp 25 degrees almost instantly to get me to the top.My allegro was 32 ft....and heavy.....454 and 456 rear end and would pull like a diesel in 3rd at low RPM....but would fall on its face if I shifted to second.....so hard pull in 3rd --heated up....but that's where it had its torque....