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Will 10w40 hurt anything?


'87quest
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My car is running the stock engine and only has 70k miles but I'm starting to burn a bit of oil so I want to try a thicker oil. I just want to make sure I'm not going to hurt anything first?

 

Thanks, Drake

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Oil isnt the issue. Using lucas and thicker oil isnt a solution.

 

Either the turbo is done, valve seals need changing, or the rubber seal under the jet valves or jet valve eliminators are done.

 

I run 15w50 on my fresh build and it smoked. Finally swappedturbos last week and am all clear. Personally Id be running 10w40 regardless of oil leaks or not.

 

Is this the original head from 20plus years ago? If so, I'd say do the valves seals and jet seals. $5 on rock auto and a Saturday of time. $20 with a fresh valve cover gasket instaled.

Edited by Malykaii
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I've been using Castrol GTX 10W-40 in the Late Fall, Winter, and Early Spring. I switch over to Castrol GTX 20W-50 during the Late Spring, Summer, and Early Fall. Been doing this since 20W-50 went on the market back when Christ was a kid.

 

The reason that I use 20W-50 in the warm/hot months is that it has a higher coking/flash temperature than the 10W--40 which gives me warm fuzzies about minimizing any coking of the engine oil in the turbo bearing oil chamber. Seems to work cuz I get about 180 to 200K miles of life out of the 2 turbo's that I've rebuilt/replaced in the past 470K miles on the Old Broad. Got about 100K on the turbo in her now. I also religiously change the engine oil & filter every 2000 to 2500 miles. Got about 470K miles on the Old Broads virgin short block including the original factory installed oil pump. But the BS's are eliminated and I'm on my 5th timing chain. Engine oil pressure is still like the day I picked her up new at the Mitsu Dealership back in '88.

 

But that's just me.

 

Another thing I have found over the years is: if you have a slightly weeping injector, which thins the engine oil over time, you'll eventually get blue smoke out of the tail pipe only on engine start up. Smell your oil on the engine dip stick to find out if it smells from gas.

 

For What It's Worth.

 

KEN

 

PS - Over the years, this has to be, at least, the 2000th post about what engine oil to use in our Starquests.

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PS - Over the years, this has to be, at least, the 2000th post about what engine oil to use in our Starquests

 

... well ay least this time he was asking a more specific question regarding wether thicker oil stops leaks, which isnt the case. Otherwise, yes, like have seen hundreds of posts, yet not a single used oil analysis. So overkill.

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PS - Over the years, this has to be, at least, the 2000th post about what engine oil to use in our Starquests

 

... well ay least this time he was asking a more specific question regarding wether thicker oil stops leaks, which isnt the case. Otherwise, yes, like have seen hundreds of posts, yet not a single used oil analysis. So overkill.

 

The below link is to one of the best combustion engine oil webistes on the web. You will get over loaded with information on the various types of engine oil, their applications and the does & don'ts, including the interpretation of the results of a 4 cycle combustion engine used engine oil analysis. There is a wealth of unbiased engine oil knowledge there.

 

http://www.bobistheoilguy.com/

 

This is for the more recent Starquesters.

 

Malykaii you are right - less viscous oil does NOT stop engine oil gaskets & seals leakage/weepage. However it does have "somewhat" of an effect on oil burning due to worn out piston rings. But as stated in the OP he only has 70K miles on his Lady's engine.

 

I recommend that '87quest:

 

1) Pulls the jet valves and gets & installs a set of jet valve eliminators from DAD.

 

2) Takes a set of hot and cold compression pressure readings to see if the piston rings are worn out due to past owner's neglect of the engine oil and/or engine over heating.

 

3) If the problem still persists - then rebuild the turbo

 

For What It's Worth.

 

KEN

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