After I got off the highway last night from driving in 20 degree temps for about 15 minutes, I check under the hood and felt my radiator hoses, and the thermostat had not even opened! I checked the oil and felt it on the dipstick and it was cool to the touch. This is with Mobil1 10w-30, my first fill with synthetic in my Corolla. With dino, it would alsways run hotter, and the oil would be at least warm-hot if touched. Is Mobil 1 that good at removing heat or what? My Grand Am was the same way, even though it knocked bad with Mobil 1. I thought normal oil temperatures were something to be achieved in cold weather to burn off moisture and fuel. At the rate I'm going with Mobil 1 and cold temps, I'd have to drag race up a lonmg hill several times to get any heat in my engine it seems! Thermostat was just replaced also and it puts out great heat from the heater.
oil and coolent temps with Mobil 1?
- Thread starter Drew99GT
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Hi,
it does take a considerable time to get the oil temps up ( called the engine's "core" temperature )on some engines
On my Porsche 928 928S4 V8 it takes about 30 minutes for all systems to reach core operating temperature. The cooling and oil systems have large volumes on this engine
Some engines will take shorter/longer times and many will simply run low oil temps during winter months and/or with short runs
In winter, some engines ( especially all alloy ) only circulate coolant within the engine as the thermostat never reaches a significant "open" stage
Some Euro engines use the radiator as a "heat sink" especially for this reason - the thermostat controls the bottom hose ( entry to the block ) and not the top hose ( exit from the block ). This avoids thermal shock and avoids intermittent low coolant temps at the bottom of the cylinder walls. It prolongs engine life because of this more stable core temperature
I have monitored my engine temperatures for nearly 12 months ( at seven points ) and in an oil change from a 15w-50 ( Shell Helix Ultra synthetic ) to a 5w-40 ( Delvac 1 ) no measurable variance has occurred over 6600kms
Regards
it does take a considerable time to get the oil temps up ( called the engine's "core" temperature )on some engines
On my Porsche 928 928S4 V8 it takes about 30 minutes for all systems to reach core operating temperature. The cooling and oil systems have large volumes on this engine
Some engines will take shorter/longer times and many will simply run low oil temps during winter months and/or with short runs
In winter, some engines ( especially all alloy ) only circulate coolant within the engine as the thermostat never reaches a significant "open" stage
Some Euro engines use the radiator as a "heat sink" especially for this reason - the thermostat controls the bottom hose ( entry to the block ) and not the top hose ( exit from the block ). This avoids thermal shock and avoids intermittent low coolant temps at the bottom of the cylinder walls. It prolongs engine life because of this more stable core temperature
I have monitored my engine temperatures for nearly 12 months ( at seven points ) and in an oil change from a 15w-50 ( Shell Helix Ultra synthetic ) to a 5w-40 ( Delvac 1 ) no measurable variance has occurred over 6600kms
Regards
I should have explained better that I was actually driving for a total of about 30 minutes up to the point where I checked the oil etc. My car has a cooling system desigened like you mentioned; where the lower hose controls the thermostat. How can that decrease thermal shock? At least on my car, the cooled coolent hits the bottom of the cylinders first as it travles back through the engine, just like any other engine?
Very few people ever notice engine/oil temp drops when using different oils. However, Series 2000 Amsoil does seem to have this ability and it's mainly due to it's Friction Modifiers. Redline as well. Mobil 1 has FM's but not the same level as S2k I would think, due to cost. So, I'm not quite sure why your seeing this with Mobil 1.
Hi,
Drew the coolant is warm not cold. In cold conditions in a "normal" cooling system the bottom hose is "cold" - in a heat sink system it is warm to hot depending on capacity and design ( coolant flow etc. ). All of the cooling system prior to the thermostat including the radiator being part of the heat sink. The top hose and bottom hose achieve almost an equilibrium
VW-Audi, Porsche and some others have used this system for some years
I must admit that even in Porsche circles it is hard for some to grasp the concept but it works very well indeed in practice
Regards
Drew the coolant is warm not cold. In cold conditions in a "normal" cooling system the bottom hose is "cold" - in a heat sink system it is warm to hot depending on capacity and design ( coolant flow etc. ). All of the cooling system prior to the thermostat including the radiator being part of the heat sink. The top hose and bottom hose achieve almost an equilibrium
VW-Audi, Porsche and some others have used this system for some years
I must admit that even in Porsche circles it is hard for some to grasp the concept but it works very well indeed in practice
Regards
My Turbo 4 Volvo's oil temp with 10W30 Mobil 1 will not get above 160F-165F on the Highway at speed if the temperature is below 40F outside. Normally it doesn't rise above 180F - 185F at 60 to 85 F. In traffic with the AC on the oil temp will rise quickly if above 75 degrees outside.
I have seen an oil temperature 290 degrees while sitting in traffic. The minute I got into clean air the temperature dropped very rapidly. It dropped faster than I ever saw the Dino oil drop from a high temperature of 220F - 230F.
I'm wondering what it will be running when the temperature drops below 10 degrees F.
It does have a factory Oil cooler.
I have seen an oil temperature 290 degrees while sitting in traffic. The minute I got into clean air the temperature dropped very rapidly. It dropped faster than I ever saw the Dino oil drop from a high temperature of 220F - 230F.
I'm wondering what it will be running when the temperature drops below 10 degrees F.
It does have a factory Oil cooler.
Doug, when I said "cooled" I meant that it passed through the radiator, not that it is cool to the touch or something
Absolutely positive that it is "no longer" stuck open. When I first bought the car, it was stuck open and I replaced it on the second day of owning the car cause it had no heat from the heater and the gauge never even moved at all from the cold position.
Hi,
Drew - what sort of car do you own?
Normal cooling systems operate the way you describe
Another feature of the heat sink system on the VW range ( all ? ) for instance is that the oil cooler ( oil/coolant exchanger & mounted on the oil filter housing )rapidly warms the oil to the cooling system's thermostat "crack" point establishing an initial equilibrium. This brings the oil rapidly out of filter by pass too
On my 928 S4 the cooling system's thermostat cracks at 83C being fully open at 98C. It is very rarely ever fully open even at 35+C ambient
with the system being stabilsed at about 85C-88C
The 928's oil cooler thermostat opens at 87C being fully open about 90C. It is a oil/coolant exchanger mounted in the radiator
My other cars have "normal" cooling systems
Regards
Doug
MY02 Subaro Outback 2.5 manual ( Delvac 1 )
MY98 BMW Z3 2.8 manual ( Delvac 1 )
MY89 Porsche 928 S4 Auto ( Delvac 1 )
Drew - what sort of car do you own?
Normal cooling systems operate the way you describe
Another feature of the heat sink system on the VW range ( all ? ) for instance is that the oil cooler ( oil/coolant exchanger & mounted on the oil filter housing )rapidly warms the oil to the cooling system's thermostat "crack" point establishing an initial equilibrium. This brings the oil rapidly out of filter by pass too
On my 928 S4 the cooling system's thermostat cracks at 83C being fully open at 98C. It is very rarely ever fully open even at 35+C ambient
with the system being stabilsed at about 85C-88C
The 928's oil cooler thermostat opens at 87C being fully open about 90C. It is a oil/coolant exchanger mounted in the radiator
My other cars have "normal" cooling systems
Regards
Doug
MY02 Subaro Outback 2.5 manual ( Delvac 1 )
MY98 BMW Z3 2.8 manual ( Delvac 1 )
MY89 Porsche 928 S4 Auto ( Delvac 1 )
The car in question is a 94 Toyota Corolla.
What I don't get is that I've expereinced the complete opposite in cooling systems as you've described. In my Corolla which apperently has the "heat sink" style routing, the lower hose stays ice cold, even when I've been driving for a while in cold ambient temps, which tells me that the thermostat is still closed. You indicated that in this style of system, the lower hose should be warm or about equal to the upper hose
The upper hose is always very very hot, even when the thermostat is obviously closed (lower hose ice cold). Geez, maybe I need to check the "calibration" of my sense of temperature or something
What I don't get is that I've expereinced the complete opposite in cooling systems as you've described. In my Corolla which apperently has the "heat sink" style routing, the lower hose stays ice cold, even when I've been driving for a while in cold ambient temps, which tells me that the thermostat is still closed. You indicated that in this style of system, the lower hose should be warm or about equal to the upper hose
Hi,
Drew - what you described is quite normal if the ambient is quite cold as you describe ( 20F/-6C )
The system will indeed be in by-pass and may stay there for the whole journey. Depending on coolant flow, the bottom hose will indeed be cooler than the top hose until the thermostat opens ( if it does ) and then a degree of equilibrium should take place but only if the ambient is high enough and the engine has been running/working long enough
As mentioned earlier some engines will run in by-pass all winter in cold climates.
How many radiators have you heard of frozen solid, heater working and car boiling without anti-freeze? The Driver saying "...but I warmed it up before I drove off..."!
Regards
Drew - what you described is quite normal if the ambient is quite cold as you describe ( 20F/-6C )
The system will indeed be in by-pass and may stay there for the whole journey. Depending on coolant flow, the bottom hose will indeed be cooler than the top hose until the thermostat opens ( if it does ) and then a degree of equilibrium should take place but only if the ambient is high enough and the engine has been running/working long enough
As mentioned earlier some engines will run in by-pass all winter in cold climates.
How many radiators have you heard of frozen solid, heater working and car boiling without anti-freeze? The Driver saying "...but I warmed it up before I drove off..."!
Regards
I seriously doubt you will see much of a temp difference between Mobil 1 and dino oil. There is just not al whole lot of difference in the frictional properties-considering that most of the engine heat is produced by combustion and not friction. I would tend to agree with the above suggestion. Thermostates fail whether new or old. I have put several stats in over my many years that were defective right from the git-go.
Hi,
Al - I agree
As well, the thermostat may remain closed slighter longer if indeed the lower frictional losses resulted in a lower oil/core temperature
Academic with normal engines due to the coolant's thermostat, light viscosity synthetic oils in Auto transmissions, gearboxes and diffs do show a measurable and sometimes very significant reduction in core operating temperature
Regards
Al - I agree
As well, the thermostat may remain closed slighter longer if indeed the lower frictional losses resulted in a lower oil/core temperature
Academic with normal engines due to the coolant's thermostat, light viscosity synthetic oils in Auto transmissions, gearboxes and diffs do show a measurable and sometimes very significant reduction in core operating temperature
Regards
For my 4 cyl camry, I discovered that oil temperatures where the same when I switched from BP Visco 7000 0w40 to Castrol SLX 0w30. When cruising on highways, it will always reach 105C. But in my climate, it still takes 20~25mins to reach this temperature. I've also discovered that the oil temperature is not affected by differences in ambient temperature. i.e. it will still reach 105C whether in the hot afternoon of 34C or the cool night of 24C.
GM claims that they could do away with the oil cooler on the Corvette by using Mobil 1 so they must have done some type of testing to come up with this conclusion. I used to run Mobil 1 in my 98 chevy truck with the 5.7L and the temp gauge seemed to run a little cooler than it does now with the Chevron Supreme conventional. Its not enough of a difference to really matter though.
Wayne
Wayne
After switching to Mobil 1 from dino HD motor oil on my Harley, there was an immediate 20 deg F drop in my oil temp measured in the oil tank (Harleys use a dry sump). This is great in the summer but in the winter I have a longer warm up than before.
Hmmm. That means you need to ride more. Still looking for the downside to that...
Hi,
Garyb80 - yes such things are noticable on bikes
Until recently I had an R100RS BMW ( flat twin ). When new I ran it in on Castrol RX Super 15w-40 and later put it on to German Castrol SLX 0w-30. There was an immediate drop in oil temperature and the thermostatically controlled ( 95C ) oil cooler was hardly ever warm after that - even in 40C weather!
Regards
Garyb80 - yes such things are noticable on bikes
Until recently I had an R100RS BMW ( flat twin ). When new I ran it in on Castrol RX Super 15w-40 and later put it on to German Castrol SLX 0w-30. There was an immediate drop in oil temperature and the thermostatically controlled ( 95C ) oil cooler was hardly ever warm after that - even in 40C weather!
Regards
Drew,
there is a guy down under who is doing some very very interesting work with the venerable 350 chev, and propane fuel.
One of his projects is a coolant inlet thermostat, that controls the coolant inlet temperature to the engine, not the outlet.
His reasoning was that he had (and we all have I'd say) seen straight 6's with a large ridge at the top of the bore on #1, and next to noe on #6. His reasoning was that #1 got cold, #6 had pre-warmed water.
Same as people driving without a thermostat, the cylinders take a beating.
So he controls the inlet temperature with a 160 degree thermostat, and each pot get 160 degree water.
An outlet thermostat lets a cylinder recieve cold water until it reaches the outlet thermostat, and closes it.
Back on topic - I made one for a v-8, and pruchased one (to help finance his testing) for a 4 cylinder.
In both cases idle RPM increased 300RPM over 4 weeks. On the quadrajet carbed V-8, I ran out of idle speed adjustment, and added a little (1/8" drill sized) EGR at idle to slow it down some.
In both cases, on a 32F morning, the top tank of the radiator remainded dead cold.
There was enough heat release from the block to keep the thermostat from using the radiator.
Both cases resulted in less idle CO, and a quite large boost in fuel economy.
there is a guy down under who is doing some very very interesting work with the venerable 350 chev, and propane fuel.
One of his projects is a coolant inlet thermostat, that controls the coolant inlet temperature to the engine, not the outlet.
His reasoning was that he had (and we all have I'd say) seen straight 6's with a large ridge at the top of the bore on #1, and next to noe on #6. His reasoning was that #1 got cold, #6 had pre-warmed water.
Same as people driving without a thermostat, the cylinders take a beating.
So he controls the inlet temperature with a 160 degree thermostat, and each pot get 160 degree water.
An outlet thermostat lets a cylinder recieve cold water until it reaches the outlet thermostat, and closes it.
Back on topic - I made one for a v-8, and pruchased one (to help finance his testing) for a 4 cylinder.
In both cases idle RPM increased 300RPM over 4 weeks. On the quadrajet carbed V-8, I ran out of idle speed adjustment, and added a little (1/8" drill sized) EGR at idle to slow it down some.
In both cases, on a 32F morning, the top tank of the radiator remainded dead cold.
There was enough heat release from the block to keep the thermostat from using the radiator.
Both cases resulted in less idle CO, and a quite large boost in fuel economy.
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