What engine oil?

[hmclaughlin67]

I have a 2005 Yukon XL with the 5.3. I have an oil leak problem, after 24 hours of sitting it will leave 2 small puddles of oil about 1.5 inch across, and one about 4 inches across. I added AT-205 to my oil a few weeks ago, and it completely resealed them and I lost no oil at all. I noticed that the puddles have returned tho, slowly at first but now they’re back to the same size. Anyways, I was wondering what brand of oil do you guys recommend? I’ve heard great things about both Mobil 1 full synthetic high mileage, but also valvoline full synthetic with the max life. My current plan is to do the oil change this weekend as it’s already needed, and then replace 8oz of oil with the AT205 to help seal up again. Also, any inquiries on the Bar’s stop leak specifically for the rear main seal? I’ve heard good things about it as well, and was wondering all of your opinions. Also was a little concerned it might be too much sealant additives at once. Thank you!

Edit: The vehicle has 203k miles and I go between 3-5k between oil changes.

 

[OR VietVet]

Mobil 1 is fine but I am not a fan of additives. Have you looked for the oil leak areas? Many threads on here about common 5.3 oil leak locations.

 

[Scottydoggs]

id fix the oil leaks vs using snake oils.

 

[hmclaughlin67]

Mobil 1 is fine but I am not a fan of additives. Have you looked for the oil leak areas? Many threads on here about common 5.3 oil leak locations.

Yes, couldn’t located anywhere for sure but seems to be the rear main. Isn’t really worth fixing when the additive works, even if it is only temporarily. I was just fishing for ideas on here as well. And the AT-205 is just the same additive they put in many high mileage oils, it’s just a chemical that conditions the seals. It worked amazing for me on many applications and I’m definitely a fan of it.

 

[blackelky]

That additive gums everything else up as well. Maybe switch to a 10w?

 

[hmclaughlin67]

That additive gums everything else up as well. Maybe switch to a 10w?

I’ve always heard that switching to a thicker oil will only hurt more. Any truth to this? Specifically, I’ve always heard that it will not reach all the small spaces it’s meant to.

 

[blackelky]

I’ve always heard that switching to a thicker oil will only hurt more. Any truth to this? Specifically, I’ve always heard that it will not reach all the small spaces it’s meant to.

Did you use gaskets or the silicone goop for your valve cover gasket reseal?

 

[Fless]

Did you use gaskets or the silicone goop for your valve cover gasket reseal?

WHAT valve cover gasket reseal?

 

[hmclaughlin67]

Did you use gaskets or the silicone goop for your valve cover gasket reseal?

I didn’t do a valve cover gasket, those are solid. It’s either the valley pan gasket or the RMS. Both I would like to avoid repairing if possible, but I will do if this next round of oil doesn’t stop the leaks.

 

[gooffeyguy]

Isn't a 10w oil only thicker than a 5w oil when it's cold?

The second number is the actual oil weight at running temp (10w-30, 10w-40, etc). So a 10w-30 oil will only be thicker than a 5w-30 oil when it's cold.