This thread is posted for folks who may be having this same problem. I had a
rebuilt 455 installed in my coach. The engine temp., from the first day,
ran hotter than the OEM engine. I didn't have a manuel water temp. gauge,
just the OEM dash gauge. Installed the manuel gauge and discovered that on
flat land the engine temp. was 215 to 220 degrees and in the mountains it
would be 230 and plus. When I told the engine builder, he changed the
radiator, water pump, fan clutch and thermostate. This helped some, but, in
order to keep my engine heat down, I could only drive 55 M.P.H. any faster
and the engine temp. soared. Went to a local speed shop that had an
engine/exhaust analyzer. This machine indicated that the carburator was the
culprit causing the engine heat. Carburator specialist cleaned the carb.
thoroughly, replaced throttle shaft bushing, installed size 74 jets, new
metering rods, idle air bleeds and high speed intermediate air bleeds.
Specialist explained that todays fuels are far inferior to fuels of just 10
years ago, (i.e.) oxygenated and reformulated and our older engine's need
to be set up to run on these. Took my coach out on the interstate with toad
and drove 70 M.P.H. with ambient air temp. 82 degrees and my engine temp.
climbed only to 190 degrees. My thermostate is a Robert Shaw part #330-180.
Since I routinely drive 60 to 65 M.P.H. I am now a happy camper. Total cost
was $350.00 for the rebuild, $45.00 for the analyzer plus tax.
Jim Bolick
'73 Painted Desert
rebuilt 455 installed in my coach. The engine temp., from the first day,
ran hotter than the OEM engine. I didn't have a manuel water temp. gauge,
just the OEM dash gauge. Installed the manuel gauge and discovered that on
flat land the engine temp. was 215 to 220 degrees and in the mountains it
would be 230 and plus. When I told the engine builder, he changed the
radiator, water pump, fan clutch and thermostate. This helped some, but, in
order to keep my engine heat down, I could only drive 55 M.P.H. any faster
and the engine temp. soared. Went to a local speed shop that had an
engine/exhaust analyzer. This machine indicated that the carburator was the
culprit causing the engine heat. Carburator specialist cleaned the carb.
thoroughly, replaced throttle shaft bushing, installed size 74 jets, new
metering rods, idle air bleeds and high speed intermediate air bleeds.
Specialist explained that todays fuels are far inferior to fuels of just 10
years ago, (i.e.) oxygenated and reformulated and our older engine's need
to be set up to run on these. Took my coach out on the interstate with toad
and drove 70 M.P.H. with ambient air temp. 82 degrees and my engine temp.
climbed only to 190 degrees. My thermostate is a Robert Shaw part #330-180.
Since I routinely drive 60 to 65 M.P.H. I am now a happy camper. Total cost
was $350.00 for the rebuild, $45.00 for the analyzer plus tax.
Jim Bolick
'73 Painted Desert
