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2008 Coolant conditioner

Improving heat dissipation or lowering engine temperature should in theory be helpful as exessive heat can over time weaken a head gasket. It's a combination of pressure and heat that ruins many head gaskets. Also corrosion from old acidic coolant, and thermal cycling. Thermal cycling or whatever its called is when the block is repetitively expanding when hot and contracting when cool, which over time has the effect of loosening gasket seal/fit.

I don't know exactly what is/or was the culprit for the

2.5l engine's problems, i.e. whether it is more heat related or pressure related, or thermal cycling related. You can fairly easily improve heat dissipation, and hope that this together with frequent coolant changes (to assure good ph levels) plus the coolant conditioner is enough to prevent problems.

Of course, you can counter argue that if it is a heat related problem, and heat is fairly easy to reduce (somewhat) then Subaru would have solved the problem a long time ago by simply increasing oil capacity by a quart or two. Well, things get complicated if you try to be rational.

I suspect the problem may be more pressure, or thermal cycling related. Reducing engine operating temperature should help a tiny bit if the failures are thermal cycling related. If purely pressure related I don't know if there is anything an owner can do to help much. Using a very thin oil could perhaps (?) make a tiny difference, I don't know.

M.J.

Reply to
M.J.
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So to test your theory you would go to all the trouble of installing extra oil cooling and then the thermostat would notices that the engine isn't up to correct operation temperature so it would compensate.

Wouldn't it have been easier to install a thermostat with a lower operating temperature.

Reply to
Bugalugs

Yes, because I am trying to reduce or dissipate heat that builds-up after the thermostat opens. At this time the thermostat cannot compensate in any way.

No, I don't think so. It would just open say 5 or 10 degrees F earlier but not help dissipate heat above its opening temp.

M.J.

Reply to
M.J.

I forgot to add, using an upper cylinder lubricant such as Marvel Mystery Oil, in the gasoline, may help reduce heat buildup in the upper cylinders by reducing friction there. This could potentially also be a bit helpful in avoiding head gasket problems. MMO is also proven to help avoid burnt exaust valves.

M.J.

M.J.

Reply to
M.J.

Hi,

Short answer: not a d___ed thing.

Long answer: if anything even measurable, it won't be much more than the original equipment design.

Even longer answer: some people miss the nature of the problem and apply even stranger band-aids than the factory. I prepared a detailed explanation of some of the factors involved in head gasket failures (none of them involved oil, BTW), then deleted it, figuring, "Hey, if someone thinks an oil cooler or bigger oil pan's gonna save their headgaskets, more power to 'em." People make good livings off that kind of thought process. Who am I to interfere?

With that, I think I'll go pop the cap on a longneck w/ Carl and not worry much about it.

Rick

Reply to
Rick Courtright

Well, me thinks that in the end you just came to your senses and deleted whatever you wrote. The main point of the argument is not oil per se but improved engine heat dissipation that extra amounts of oil ,or an cooler, facilitates. The temperature reduction argument, as an argument is fairly strong, so why pick a fight you cannot win, right?

Let me say this, I never claimed that an engine oil cooler, or bigger pan, is the solution. My opinion is that together with the coolant conditioner it is probably worth the money. An extra edge of sorts, quite possibly the only thing that a proactive owner can easily do, that is also good for overall engine longevity.

M.J.

Reply to
M.J.

Here is an interesting take on high engine oil temps and head gasket failures:

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temperature as a potential cause of HGF: It has been suggested that HGF maybe more likely in cars running with high oil temperatures.

Why?

Because of the following reasons:

1.. HGF is caused, at least in part, by the movement of the cylinder head over the block, which causes the head gasket's rubber beeding to fail through shear stress, and thus lead to escape of coolant. 2.. This movement is caused by engine block twisting under high torque loads, and also - the import bit for this discussion - due to differential expansion due to different temperatures in the head and the block. 3.. The cylinder head is primarily cooled by water. The block is primarily cooled by oil. 4.. Under high loads, the engine temperature increases (more work, more heat). This heat is disappated by the oil and water circulation. Oil is cooled by heat radiation into the airflow under the car (marginal in a mid-engined vehicle) whilst water is cooled by the radiator; water cooling here is much more efficient due to that large air/water heat exchanger known as the radiator. 5.. If the engine is working hard, the oil temperature will continue to rise, whilst, due to the opening of the thermostat, the water temperature is reduced. 6.. Water temperature is lower than the oil temperature. This means that the cylinder head is cooler than the cylinder block: the block and the head will expand at different rates = shear stress on head gasket. 7.. Temperature gradient problem is exacerbated when the thermostat opens and allows cold water (that has been sitting, being cooled by the airflow through the radiator) to enter the cylinder head. Suddenly, the head is even colder than the cylinder block... head contracts, whilst block expands = significant shear stress on head gasket. So, given this premise, if your engine's oil temperature is regularly above 120ºC, the problem with differential head/block expansion is going to be significantly worse than when the oil temperature remains in the 90-100ºC range (closer to the 'regulated' water temperature).

Based on these premises, a water/oil heat exchanger may be beneficial in matching cylinder head and block temperatures, and limit the heat expansion mediated shear stress on the head gasket.

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Reply to
M.J.

Why not just buy the 2L, 2L turbo or the 3L.

It is my understanding that the problem was when the 2L block was opened out to 2.5L.

This left less space between the cylinders and the oil/coolant passageways where they passed through the head to the block.

The original and the first redesigned gasket was not adequate.

No amount of extra oil cooling is going to solve that.

The second redesign and the current designs have solved the problem.

'course I could be completely wrong

Pass one over here too will ya

Reply to
Bugalugs

There isn't much choice here in the States, where Subaru sells only two engines, the 2.5L and the six cylinder.

M.J.

Reply to
M.J.

Got one iced up w/ your name on it, Bug!

Rick

Reply to
Rick Courtright

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