Observation with Rislone

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My daily driver junker truck is a 1992 F150 with the 4.9 . . . Operating temp is always just under 210F (read on a mechanical gauge).

To try and quiet a lifter tick, I added a bottle of the Rislone concentrate to the Traveller 15w-40 that's in it, probably at about the middle of an OCI.

Truck was/is immediately running about 5 degrees cooler. Nothing else was changed.

I don't think it was any reduction in viscosity, as it ran the same temp on SN 10w-30.

Any thoughts?
 
Originally Posted By: kschachn
My first thought is that I'm surprised the thermostat isn't regulating it to the set temperature.


True
It should still run the same temp.
 
Originally Posted By: kschachn
My first thought is that I'm surprised the thermostat isn't regulating it to the set temperature.


Only to some extent under ideal conditions. Example.. In stop and go bumper to bumper traffic on a hot summers day the fan(s) may not be bringing enough air across the radiator to extract the heat from the coolant as air coming through it at driving speeds. It can and many do eventually overheat.
The thermostat cant open more than fully.
A reduction in friction will reduce the amount of heat generated inside the engine and absorbed by the cooling jacket. Make sense?
 
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I 'blame' the 210ish temps to an old/partially clogged radiator . . . but it's consistently run there for years.

I can watch the thermostat open and close (it's a 195F) but I'm not measuring temp at the thermostat housing . . . the bulb is basically in the water jacket between cylinders. Temps vary depending on where you're taking the measurement.

. . . example, assuming the thermostat is close to accurate at 195F . . . when coming up to temp, my gauge goes to 215 before the 195 thermostat opens and drops it back down. Water temp is a 'localized' measurement, not average. Thermostat housing is getting less heat generated and much more airflow than the side of the block.

Once you're consistently over 195 (which you should be for fuel efficiency) it's the radiator's job to regulate the temp.

I haven't worried too much about the temp. Just curious about the drop.
 
Originally Posted By: Trav
Originally Posted By: kschachn
My first thought is that I'm surprised the thermostat isn't regulating it to the set temperature.

Only to some extent under ideal conditions. Example.. In stop and go bumper to bumper traffic on a hot summers day the fan(s) may not be bringing enough air across the radiator to extract the heat from the coolant as air coming through it at driving speeds. It can and many do eventually overheat.
The thermostat cant open more than fully.
A reduction in friction will reduce the amount of heat generated inside the engine and absorbed by the cooling jacket. Make sense?

The first one, yes. The second one no. In order for the second scenario to work and actually lower the temperature of the coolant would require him to magically be operating right at the heat load that just barely keeps the thermostat open. Otherwise the thermostat would just throttle down slightly and keep the same temperature. Overall heat rejection lower, OK I'll envision that. But not a lower temperature. That's controlled.
 
Right. As long as the engine was still controllable by the thermostat your right. If the thermostat was wide open and air movement was not drawing as much heat as being generated then a reduction in friction will reduce the temperature.
By how much I have no idea as most of the heat is from combustion being transferred to the cooling jacket.
 
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I think the Rislone might have thinned the oil which in turn cooled the engine better than the 15W40 was.
 
Cap is fine and thermostat is fine, both are about 1.5 years old . . . truck has run this oil and this temp for about 100,000 miles and ran the same temp with the predecessor rad cap and thermostat (that I changed out when I replaced the original water pump (at the 25 year mark).

Yes, 210F is close to boiling . . . with no glycol and no pressure.

The good cap and pressure are exactly what allows it to run just fine at 210.

210F is absolutely normal operating temp for the majority of 'modern' engines out there, dummy gauges have just made us forget that.


I don't think that it was the thinning of the oil that reduced the temps . . . truck ran the same temp with 10w-30.
 
Throw in some MMO and really watch this thread take off.


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The Rislone product is about a 20 grade oil so a reduction in oil viscosity is possible.


Using a 15W40 in an engine engine speced for a 30 grade oil will raise engine temperatures slightly, so if the 40 grade temp was lowered by the thinning the oil with a 20 grade, the temp difference might be a few degrees.


Rislone can clean certain engine components such as VVT valves and hydraulic lifters.
 
How many quarts does your crankcase hold?
The Rislone may need longer to work. Or it may need another 16.9oz application, a thousand miles prior to an oil change. I've used it with success in the past. Any engine that holds more than four quarts may need more than just 16.9oz. I know Walmart sells the Rislone in quart bottles and I've had better results using the quart bottle over the Concentrate.

It's probably too late to add the quart bottle. That will thin the oil too much. So try another 16.9 if need-be..... should your crankcase hold 5-6 quarts capacity, using a thicker oil like 15W40.

Just my opinion -- my experience working at home with Rislone and gas-driven engines in the past 45 years.
 
Originally Posted By: MVFarms
My daily driver junker truck is a 1992 F150 with the 4.9 . . . Operating temp is always just under 210F (read on a mechanical gauge).

To try and quiet a lifter tick, I added a bottle of the Rislone concentrate to the Traveller 15w-40 that's in it, probably at about the middle of an OCI.

Truck was/is immediately running about 5 degrees cooler. Nothing else was changed.

I don't think it was any reduction in viscosity, as it ran the same temp on SN 10w-30.

Any thoughts?


It is possible, 5 degrees F is quite minimal and it is possible to be impacted by additive added. I have similar observation with Lubegard added to the oil as well. It keeps engine oil temperature colder by 1-2 degree Celcius and the engine takes longer before reaching operating temperature.
 
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