I typically use a 160 degree thermostat on all of my engines. After many
hundreds of thousands of miles experience I feel its a good choice. My
reasoning is that heat is a major factor in the thinning and breakdown of
oil. With the 160 degree thermostat, after 3000 miles, my oil still looks
like honey.
>You're correct, it was 15w-50 Mobile One I used rather than 20-50. What I
>saw was, that with the 160 degree thermostat, the oil pressure indicator
>(stock gauge) would be nearly pegged to max most of the time ....
The stock oil pressure gauges are often not very accurate and are certainly
not very linear. I would suggest testing your oil pressure sender. I used
compressed air to test mine and made a note of the actual pressure for each
tick mark on the dash gauge. The full scale reading was 60psi.
>If I had kept the 195 thermostat, it would have been lower.
Maybe a little lower but my experience is that its not a lot lower. The
Mobile-1 15W-50 does not change viscosity very much over the temperature
range.
>I'm a believer in the theory that you only need 10 psi of oil
>pressure for each 1000 rpm.
I am using Quaker State 10W-40 with a 160 degree thermostat and I get about
50psi at 2600rpm.
>My only concern with the 160 deg thermostat is that the engine is
>getting warm enough to burn out the moisture in the crankcase on moderate
>drives. I know it does on long trips.
My experience is that the 455 comes up to temp very quickly. I have never
seen any signs of moisture build-up in any of my engines that use the 160
degree thermostat. You may have a problem with very short trips in cold
weather (below freezing) but that is also true of a 195 degree engine as
well.
>What are you thoughts?
My thinking is that the 195 degree thermostat is a product of 1970's
emissions requirements. Prior to the 70's, most engines ran at lower temps.
If I recall correctly, car engines where set to 180 degrees (so the heaters
would work well) and truck and tractor engines where run at 160 degrees to
minimize wear.
I would not worry about the high oil pressure unless you suspect that there
is a blockage somewhere. When it comes to oil, higher pressure is usually
better.
Also, keep in mind that the engine thermostat is only half of the
temperature control system. There is also a thermostat on the fan clutch.
Once the outside air temp gets to about 75 or 80 degrees, the engine
thermostat will be fully open and the fan clutch will control the engine
operating temp. So if you really want to keep the engine at 160-170 degrees
during the summer then you will have to adjust the thermostat on the fan
clutch. Of course the trade-off is the fact that the fan makes more noise
when its warm outside.
Dave
Ann Arbor, MI.
73 Sequoia (26'/455/EFI/HEI)
hundreds of thousands of miles experience I feel its a good choice. My
reasoning is that heat is a major factor in the thinning and breakdown of
oil. With the 160 degree thermostat, after 3000 miles, my oil still looks
like honey.
>You're correct, it was 15w-50 Mobile One I used rather than 20-50. What I
>saw was, that with the 160 degree thermostat, the oil pressure indicator
>(stock gauge) would be nearly pegged to max most of the time ....
The stock oil pressure gauges are often not very accurate and are certainly
not very linear. I would suggest testing your oil pressure sender. I used
compressed air to test mine and made a note of the actual pressure for each
tick mark on the dash gauge. The full scale reading was 60psi.
>If I had kept the 195 thermostat, it would have been lower.
Maybe a little lower but my experience is that its not a lot lower. The
Mobile-1 15W-50 does not change viscosity very much over the temperature
range.
>I'm a believer in the theory that you only need 10 psi of oil
>pressure for each 1000 rpm.
I am using Quaker State 10W-40 with a 160 degree thermostat and I get about
50psi at 2600rpm.
>My only concern with the 160 deg thermostat is that the engine is
>getting warm enough to burn out the moisture in the crankcase on moderate
>drives. I know it does on long trips.
My experience is that the 455 comes up to temp very quickly. I have never
seen any signs of moisture build-up in any of my engines that use the 160
degree thermostat. You may have a problem with very short trips in cold
weather (below freezing) but that is also true of a 195 degree engine as
well.
>What are you thoughts?
My thinking is that the 195 degree thermostat is a product of 1970's
emissions requirements. Prior to the 70's, most engines ran at lower temps.
If I recall correctly, car engines where set to 180 degrees (so the heaters
would work well) and truck and tractor engines where run at 160 degrees to
minimize wear.
I would not worry about the high oil pressure unless you suspect that there
is a blockage somewhere. When it comes to oil, higher pressure is usually
better.
Also, keep in mind that the engine thermostat is only half of the
temperature control system. There is also a thermostat on the fan clutch.
Once the outside air temp gets to about 75 or 80 degrees, the engine
thermostat will be fully open and the fan clutch will control the engine
operating temp. So if you really want to keep the engine at 160-170 degrees
during the summer then you will have to adjust the thermostat on the fan
clutch. Of course the trade-off is the fact that the fan makes more noise
when its warm outside.
Dave
Ann Arbor, MI.
73 Sequoia (26'/455/EFI/HEI)
