Hello,
I'm new to the forum. I'm having a problem with a 84 Excalla 28ft motorhome wanting to run at the top end of the temperature range. about 250 degrees according to the temp gage. I have removed the radiator and had it cleaned and rodded, relaced the water pump, all hoses and belts, new coolant, Prolong oil additive, oversize oil filter. It still wants to run hot. The coolant never boils over but this has to be causing a lot of ware to this engine. I purchased this RV about 6 months ago from the original owner, it has 26000 miles on it. It was very well maintained and pamperd it's entire life. I have had a tune up, replaced plugs, air filter, didn't replace the distributor cap or rotor. The engine is a 454 Chev. Any help would be appreciated.
thanks
darrell
Hi Darrell, welcome aboard!
Are you using the original water temp gauge?
If its only 10% off (hopefully to the upside) ,
you could be running at 220.
My personal opinion is running the 454 at 220 is about max. A good operating temperature in summer with A/C on is about 180-200, with temporary max of 210-220, when climbing steep hills.
If you are really running at 250, your fan clutch would never disengage. Are you aware of the clutch engaging?
The fan does kick on when I start to slow down say from highway speed entering into town. It has a idiot light on the dash that pretty much stays on all the time, as well as a temp gage. How would you go about determining the actual temperature? Oh, I did replace the thermostate with a 180 degree and heat sending switch, also. forgot to mention in previous post.
thanks
darrell
you can go with a new mechanical temp gauge or a new electrical. Either way, you will have to replace the sending unit.
Your description of the fan clutch engaging is very similar to mine. Hardly ever during highway speed and more frequently in city traffic.
As I understand it, most fan clutches engage when the temperature at the radiator reaches about 225 degrees. If that holds true in your case, it would be doubtful that you are running at 250.
Since you replaced most of the cooling components (assuming a heavy duty 4 row recore of the radiator), other mechanical items would be wrong plugs, timing off, worn timing chain and fuel delivery problems.
I agree if you were at 250 degrees the fan would be on all of the time. Mine kicks in at about 220. It also goes on when slowing down or pulling on a hill. My guess is the temperature gage or sensor is bad. One way to reduce the temperature is to wire the A/C fan to a switch. The A/C fan goes on only when the A/C is running and the coolant temperature gets to a certain value. I wired mine to an auxiliary switch which I mounted on the dash. I run this all of the time in warm weather. It also works great when you stop for a short time to get rid of the engine compartment heat.
To check your heat sensor/gage you can get a temperature measuring strip that can be mounted to the transmission case. I have seen these and they can be reasonably accurate.
Hey fellows,
Thanks for the insight. I have since found a old time drag racer here local, who is well known for his engine abilities especially carbs and he is going to do a examination in the morning on the Starcruiser. Will post findings later.
thanks again,
darrell
My temp gauge (for reference) stayed at 160 most of the time, on 92 degree and higher days, driving up interstates north thru the mountains of NC and VA. When it hit 180, the fan would kick on and bring it back down to 160 again where it cut out. In town driving it would come on once in awhile at a slightly lower temp and then kick off again at 160. I also checked my anti freeze to be sure I did not have a too high mix relative to water.
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