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1turbofocus 12-03-2011 09:12 AM

Engine Oil Weight
I got a scolding from a member wanting to know why I would give him bad advice about running a higher then 20wt engine oil in his car

He stated after talking to many people that running higher then 20wt would "blow the seals, and the head gasket " This has to be the dumbest most moronic thing I have ever seen , engine oil blowing a head gasket ???

There is no more PSI on the seals or the head gasket with 50wt then there is with 10wt

Running 20wt oil is fine if you driving the car normal back and forth to work and to the grocery store or in the winter under extreme cold conditions , once you start modding your engine you need more protection with a higher wt oil , I run 40 in the winter and 50 in the summer but most dont have turbos and making the power I do

The engines I build I tell most to run 30or40 winter and 40or50 summer depending on there HP and what they use it for, this is my opinion/advise it does not mean this is what you have to do

I would love for the guy that told him he would have head gasket issues to post and explane

Please post your oil opinions about going to a higher WT oil for better protection


FocusBoy58 12-03-2011 09:24 AM

5w40 mobile 1 synthetic with 1quart of Original Lucas Oil Stabilizer, Turbos like to leak with thin oil. Never had an issue. If you want best gas mileage sure run 5w20
you want protection for your investments then put thicker oil.

Roushturboedzx3 12-03-2011 09:39 AM

someone said they would blow a HG from a different oil LMFAO.

just for reference i run 10w-30 RP year round

1turbofocus 12-03-2011 09:50 AM


Originally Posted by FocusBoy58 (Post 3915954)
5w40 mobile 1 synthetic with 1quart of Original Lucas Oil Stabilizer, Turbos like to leak with thin oil. Never had an issue. If you want best gas mileage sure run 5w20
you want protection for your investments then put thicker oil.

I dont agree that 20wt gets better MPG then 30wt or 40wt, and my opinion is things like lucas and rp is its not worth running

I build a LOT of race engines and a lot of the competition runs things like lucas , rp etc and they dont run as long or longer then the guys running std Syn oils


Bradm 12-03-2011 10:17 AM

Multi viscosity oils like 5-20 or 5-30 are using the same base, 5 wt. The viscosity changes by heat coiling or uncoiling little polymer chains. Cold they are balled up, warm to hot they stretch out effectively thicken the oils weight. Point is they are the same base oil and change at unknown temps for the user.
Adding some oil modifier then again changes the oils behavior in unknown ways, could be thicker or not. A user w/o a lab or testing just has no idea what is going on. Any statement of what change to the viscosity change or rate of change is just blowing smoke.

Lighter weight oils do reduce fuel consumption but usually only for brief cold engine operating temps however these lighter oils also are more effective in moving oil at low rpm steady state throttle conditions.

A number of engines also require the lower viscosity to reduce valve train and crank drag to see the design hp/torque. Some engine valve trains can see "coking" because the heavier weights are staying on the valve components for too long of a period versus a lighter weight moving off the components quicker.

Most all of the above is directly related to a stock engine, one buit for performance has other needs and requirements in some instances it is the user/builder to decide how far the build is off oem specs in regards to the critical concerns. Valve train remains the same but at a higher operating rpm level a slightly heavier weight may be called for.

Heavier weight oils with low pressure pumps won't blow a head gasket but could plug by coking off a piston cooling jet though for example.

1turbofocus 12-03-2011 10:35 AM

I DO NOT agree that a heavier oil causes coking any more then a lighter wt oil would in most cases coking is cause by not changing the oil , running the oil hot and other causes a 50wt oil at 200 deg isnt going to stay on a part any longer then a 20wt oil will

"Heavier weight oils with low pressure pumps won't blow a head gasket but could plug by cooking off a piston cooling jet though for example. "
Does this mean a heavy wt oil with a high psi pump would causea a head gasket to blow ? and even if a jet was to stop up you wouldnt loose an engine , if that was the case then every Zetec engine out there and every 350 , 302 chevy and ford would be blowing up

I also feel a "stock" engine with modding and running it harder then built to do needs a higher wt oil for better protection

Im not trying bust your ba$$s just there is so many "opinions" that it leads people to believe things that are not true


FuriousFocus 12-03-2011 10:50 AM

Honestly, for me, I think its more a fear of the unknown running 10W40 in my Zetec vs what Ford says I should run. I've been running 5W30 in my Zetec for 5 years - car has 81,000 on it and will be ten years old in April with the original oil and water pump. I would not run 40Wt in my motor because I don't see a need for it when Ford says 20Wt is best. If I was racing the car I would use a higher WT oil, probably 40Wt, to keep the oil from being too thin at constant high temps.

PS, Tom your base tune really woke up my car, thanks again.

FuriousFocus 12-03-2011 10:53 AM

As for the head gasket thing, I don't think there would be any issues with higher wt oils. Especially a 5 or 10W40 or 50Wt.

Bradm 12-03-2011 12:04 PM

Can't have it both ways. Either the heavier weight offers more protection by staying with a part longer and retaining more heat or it does not offer any additional protection because it leaves the part as quickly.

I never stated a head gasket can be lost by any oil. What I did say were passages could be coked by the wrong viscosity. Some manufacturers have refused warranty claims on the top
end by testing the engine oil the user was running, Ford for one with early 90's escorts, Chev w/ C4 vettes and Dodge and the 2nd gen Viper.

Oil is much like religion some are basing their choices or use based on faith and not empirical evidence. Personally I run oils based on manufacturers recommendations and specifications except on the bikes where I have some oils work better based on my testing. To each their own.

1turbofocus 12-03-2011 12:04 PM

Ford says what oil to use for what they built the car for once you change that you should also change plugs , thurmostat , oil wt

The Ford focus stock was built to run rpm of about 1500 to 3500 on Avg so 20wt will be fine when you change that ????


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