Going from a heavy weight to a light weight oil

[Falcon_LS]

My buddy's father recently purchased a '07 Grand Marquis with 50,000 km (31,250 miles) on the clock for his 23 year old daughter. It's a fully loaded LS in immaculate condition with the Handling Package, but the previous owner decided to go against Ford's 10w30 oil weight recommendation. Instead, he used Mobil Super XHP 20W-50 sourced from the UAE, which is an API SL rated oil. Oil change intervals were 5,000 km (3,000 miles). According to the previous owner, it's the 'best' oil for this application and a 10w30 SM/GF-4 rated oil is 'rubbish'.

I showed my friend and his father pictures of what my truck's valve train looked like, running UAE sourced oils with 5,000 km OCIs, and they are convinced that they want to clean up the valve train.

Now the tricky bit is his father wants to follow the American oil weight recommendation of 5W-20 (using Pennzoil conventional) with 8,000-10,000 km (5,000-6,000 mile) OCIs. This what his '06 Expedition has been running since late '05 (for 98,000 km/61,250 miles) and he wants the Grand Marquis to be no different.

Question is, what should we expect switching from 20W-50 to 5W-20? Would this be a bad move, considering 20W-50 is all this engine has ever run? I told them Motorcraft Premium Syn Blend 10w30 would suffice, but they are dead set on 5W-20 (Pennzoil conventional).

 

[bepperb]

It probably would be fine, but as with anything it might be best to apply the change over time to a 30 now and a 20 later. That way if things are louder with a 30 weight, you'll know you're headed in a direction you don't want to go.

 

[jimvegas]

You should expect better power and a more freely revving engine. Not to mention better fuel mileage.
20W50?! Geez.....

 

[Geonerd]

I can't see how the running thicker oil would 'acclimate' the motor to the syrup. As such, the 'switch' is not the issue.
I'm FAR more concerned about 5w-20 being incorrect according to Ford. If the manufacturer specs xW-30, you'd better run something at least that thick!

Also, while Pennzoil Conventional is fine stuff, I don't see it as being god's gift to a dirty valve train.

 

[dnewton3]

I think that the switch will be just fine; I see no issues with running the 5w-20.

If you're concerned about some build up, consider the use of ARX. I was astounded at the results I got.

 

[demarpaint]

Over a lot of miles a engine can develop a wear pattern. There is a slight possibility going down a few grades in oil viscosity might show some consumption. Since this engine doesn't have a lot of miles the change will probably be no problem at all.

 

[PT1]

Just dumpin the 5w20 and be done with it. Wait 2 OCI's to evaluate. I would use PP.

 

[Gary Allan]

Just make sure consumption is monitored for a couple of OCI's. By that I mean more frequently. No need for "well my other car didn't use any".

 

[Bryanccfshr]

The Pennzoil Conventional 5w20 will be great! Just make sure they are monitoring for consumption since first the engine may consume oil and second the oil control rings are actually going to get oil flow and consumption may occur of an OCI or two until the top ring is accustumed to getting lubrication.

Other than that this is a young engine and will provide many years of service on 5w20.

the 10w30 recomendation was like many US exports based on presumed product availability. Since the Father in this case has 5w20 on hand I suppose this is no longer an issue.

 

[CROWNVIC4LIFE]

Originally Posted By: bepperb
It probably would be fine, but as with anything it might be best to apply the change over time to a 30 now and a 20 later. That way if things are louder with a 30 weight, you'll know you're headed in a direction you don't want to go.

+1

 

[crazyoildude]

use the 5w20
20w50 in a modular v8 will seriously shorten its life
and you can expect more power and better gas mileage and a smoother running engine that will last a long long time with the 5w20

 

[crazyoildude]

5w20 is what ford says to use at least in the United States that is the only weight they say to use in an 07 Grand marquis with the 4.6
Are you out of the U.S. ? i have heard they want to use a thicker oil in some places...
Most all of the Police departments and taxi drivers use 5w20 i have heard that the New York State Troopers used the 20w50 one winter and needed a few rebuilds due to the filter blowing out..

 

[Audi Junkie]

Wait a minute. Is this in Kuwait? Don't you have to run vehicles at idle to cool-down after driving there? If so, I would never run a 5w-20 there, not even a 10w30 unless I had an oil temp gauge. 15w40 HD would be a "light oil" for those conditions.

 

[crazyoildude]

thicker oils run hotter than thinner oils for the most part

 

[OVERKILL]

Originally Posted By: crazyoildude
use the 5w20
20w50 in a modular v8 will seriously shorten its life
and you can expect more power and better gas mileage and a smoother running engine that will last a long long time with the 5w20


I'm sure you have plenty of proof to be able to substantiate that 20w50 in a Modular in Kuwait is going to shorten it's life....... right?

 

[JohnBrowning]

The engine does not know it has been run on 20W50 it is not like it enlarges it's clearances to make space for te thick oil....Unlike the elastic in your underware engine clearances remain the same until they are changed by wear. In that temp./climate 20W50 is probably close to what 10W30 is in Michigan. I do not think any harm was done at all to the engine.

Now with regards to switching some older engines never liked 5W20 and some did not mind one way ot the other. We have heard from more then one ford owner that has claimed 5W20 did not run well in their engine. Obviously the smoothness of idle and noise from the engine are not good ways to tell much about an oil but that is what we have.

My Toyota 4Runner was run of Castrol GTX 20W50 from 1986 to 1992 when I bought it off Dad. Then I switched it to Mobil 1 15W50 year round for a year prior to going to college. When I went to c9ollege I ended up running Mobil 1 5W30 dureing the winter and Mobil 1 15W50 dureing the summer so it all worked out just fine. I never had consumption issues or abnormal wear or anythign like that!

So to sum it up you should be fine! Any viscosity recommended by the OEM will work 100% of the time. The OEM cannot make a single recomendation and have it be the best fit for that power train operated around the world their is no such thing as a universal oil viscosity!As long as oil changes where done often enough and the air filter was maintained that engine should be fine!

To be honest in the middle east I would be more concerned that a qualtiy paper filter was used or a farbric type with foam pre-filter then I would be about the oil!

 

[Gary Allan]

It won't shorten it any more than 5w-20 will in Canada. I'm sure that both transition through the same visc in their respective environments.

That's why most viscosity arguments are bogus. Every oil is too thick at start up. If 20w-50 is destroying modulars in Kuwait at high noon....then 0w-10 is doing it in PA at 0C

 

[OVERKILL]

Originally Posted By: Gary Allan
It won't shorten it any more than 5w-20 will in Canada. I'm sure that both transition through the same visc in their respective environments.

That's why most viscosity arguments are bogus. Every oil is too thick at start up. If 20w-50 is destroying modulars in Kuwait at high noon....then 0w-10 is doing it in PA at 0C



Exactly. I imagine much of the year up here, 5w20 would be as "thick" as 20w50 is in Kuwait.

 

[crazyoildude]

i have never been there but here in new jersey i see proof often in the cold winters i have seen the state troopers when they started using the vics with the 4,6 v8
I have seen with my own eyes in my engine shop more than one oil filter "blow out" on a vic P.I. there were some that thought there were engine problems with these cars then... The N.Y. state police had the same problem using 20w50 in the winter.. What would happen is using the thick oil and getting into a cold car with a cold engine starting it and punching it and pop there goes the oil filter and then the motor! I don't remember what filters they were using but each Barracks uses what they like...Back then around 9 years ago 20w50 was the oil a lot of people still used.. Everyone learned from this i was there in my shop when the ford rep and one of the filter companies were there so yes i have proof, i also believe that if your car requires 5w20 then you should use it the car companies spend millions in research maybe even more than you do.. When ever someone askes my opinion i am happy to answer them if they listen great if they don't i can do the rebuild and great to that also.. And there my friend that is the same proof that everyone else in the know uses..

 

[OVERKILL]

That was possibly the longest run-on sentence I have ever read

But regardless, you didn't provide any proof because you used New Jersey as an example. He lives in Kuwait!!!! Do you have ANY idea of the difference in ambient temperatures between those two places?

And of COURSE an engine that blows its oil filter off is going to potentially be damaged!

BUT

This guy is not living in Antarctica. He is living in Kuwait. Subsequently, he is not starting this car in the extreme cold. He is starting it in the extreme HOT!

It is VERY likely, as Gary touched on above, that his coldest oil viscosity is probably LIGHTER than what 5w20 would be up here in Canada for much of the year!

After all, visc is temperature dependent.

If he said "I live in Jersey and want to run 20w50 in the middle of winter", then you would have a point. But that is the polar opposite of this scenario. Thus making your statement baseless.

I am not condemning your logic completely here, though I'm sure it seems that way. The scenario you alluded to makes perfect sense..... When considering its geographical stipulations. The issue is, you didn't consider HIS geographical location when making that statement.