Synthetic Oil in 1987 5th Ave with 37K original miles?

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chaffin67

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I recently purchased a 1987 Chrysler 5th Ave with only 37K from the original owner in California and then drove it home to Idaho. The car is exceptionally clean and runs and looks excellent both inside and out. It was well maintained and was always garaged.

I just changed the oil last week and thought the best thing I could do was to upgrade to Mobil 1 full synthetic extended range......wanting what I felt was the best way to baby the car.

Found this forum tonight and really feel I found a great resource but was surprised to see a couple of postings sharing that Mobil one should not be used, and I should have stuck with a high quality 10W-30 conventional oil.

This car is leak free and a real survivor so the last thing I want to do is create a problem.

SO.....what does everybody think? Am I ok? or should I go change this quickly? It has only been driven about 20 miles with the synthetic.

Thanks for your wisdom in advance-
5th 1.jpg


5th 1.jpg
 
First off....
Welcome aboard.
That's a gorgeous Fifth.

If it were me.
I'd change it immediately to conventional 10W 30. New filter too.
Years ago I asked a very well respected mechanic friend of mine about going synthetic He gave me a filthy look and said "That thing came from the factory with conventional and has done just fine for almost 30 years....don't go f***ing it up now."

I listened.
In my opinion synthetic is for rice engines or newr style ones anyway. A cast iron 20 something year old Chrysler needs good old conventional.
 
I always use Mobil..I've always been told it's one of the better ones out there, just dont use the synthetic on these cars.
 
What's the saying ? "6 of one, half dozen to the other". A debate that has no ending. When it comes to oil. Some will swear by synthetic,others conventional.I myself go back and forth on many different cars and really don't see a difference.One thing for sure most of us change oil often way sooner than most. Just a thought.....
Enjoy the site and that fine automobile.
 
For our cars, both conventional oil and synthetic can be an issue. Just using modern conventional oil is not a solution, due to the reduction of ZDDP, a zinc/phosphorus compound that was used to reduce flat tappet/camshaft wear. Newer oils, in order to meet emissions requirements (ZDDP can poison catalytic convertors and coat O2 sensors when it gets into the exhaust stream), have pretty much reduced ZDDP content to the point that it can no longer prevent wear, or have eliminated it entirely.

See the "Reformulated Motor Oil" section in this article:

http://www.hotrod.com/how-to/engine/flat-tappet-cam-tech/

Another article that discusses not only the lack of ZDDP, but synthetic oil as well:

http://www.superchevy.com/how-to/corp-0808-worn-down-engines/

I found the note regarding synthetic oil being "too slippery" to allow for lifter/pushrod rotation of interest.

I don't remember if there were roller cam LA engines in 1987. If they are roller lifter engines, I don't think the synthetic will do any harm. If they were flat lifter engines, I would think that the conventional oil (Rotella T conventional, racing oil, or something like LUCAS Hot Rod and Vintage car oil, which I have seen and specifically states that it has an extra load of ZDDP) would be best.
 
If I was running a 1975 or older motor, then I'd be using Z-Alt motor oil.

Besides the too slippery, synthetic doesn't burn off and older carbed cars will get some blow by.

I only use Baldwin oil filters.
I saw the tests.
Baldwin #1, WIX a distant #2 and the rest suck.
And when a real Mopar garage proves even Mopar filters suck, I'll listen and use Baldwin.
 
From all I've read on Mopar engines I don't think zinc is a real issue with the low thump of a smogger 318.
Even my older slants have been doing just fine on straight conventional. An older performance engine? I'd definitely be going the zinc route
 
Even the low power, smogged, low compression 318s use flat tappet lifters. While undoubtedly, they don't have the valve spring pressure of the higher performance engines, the friction levels where the flat tappets (and I do understand that they are NOT perfectly flat) meet the cam lobes are still quite high. Even if the 200,000 PSI number quoted in the Hot Rod article was exaggerated (proabably was to some extent), and the pressure is only 30,000-50,000 PSI, that is still a tremendous load. Adding in a little insurance in the form of diesel engine motor oil (conventional, of course) or going the extra mile and getting specific high ZDDP doesn't seem to be excessive. Its proabably an extra $20-25 per oil change, maximum. Maybe not needed? Maybe. Only time you would know is when you took the engine apart.
 
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Thanks for taking the time to respond, I appreciate your wisdom and I will be changing the oil and filter quickly-Love your rides, with the exception of the scamry! LOL
 
kkritsilas said:
Even the low power, smogged, low compression 318s use flat tappet lifters. While undoubtedly, they don't have the valve spring pressure of the higher performance engines, the friction levels where the flat tappets (and I do understand that they are NOT perfectly flat) meet the cam lobes are still quite high. Even if the 200,000 PSI number quoted in the Hot Rod article was exaggerated (proabably was to some extent), and the pressure is only 30,000-50,000 PSI, that is still a tremendous load. Adding in a little insurance in the form of diesel engine motor oil (conventional, of course) or going the extra mile and getting specific high ZDDP doesn't seem to be excessive. Its proabably an extra $20-25 per oil change, maximum. Maybe not needed? Maybe. Only time you would know is when you took the engine apart.
Click to expand...

My two slants are flat tappet but the 318 is a roller.
 
And when they where engineering these motors, what oil where they using?

When it comes to synthetic oil in my M and F's, I'll go what the engine gurus tell me.
When a guy like Herb 'Mr. 4-Speed' McCandeless, who bleeds Mopar, laughs at Mopar filters and using synthetic on my motors or someone like Dick Edlebrock says the same thing....among other Mopar engine builders, I'll listen to them.

If you have a pre 75, these guys claim Z-Alt is the one.
But they said Z-Alt isn't gonna do anything for my cars.
 
Welcome, That is a really nice car and color combo. I don't think you could get better advice on oil for these cars than the responses so far. I have had experience with synthetic oil in older engines that don't leak oil, and then after you switch, the slippery synthetic finds its way out of a main seal. I run Valvoline conventional 10W30 in my 1988 Fifth.
 
Don't be scared of synthetic oils. I have been an Amsoil dealer for years, and have run it in many carb'ed Chrysler's, and Jeeps with Zero problems. What is key here is to use a quality synthetic oil. Mobil 1 is a more low quality product to keep it cost competitive. You can run a quality Synthetic in a carb'ed motor for 20,000 miles with NO issues. Amsoil was developed in the early 70's, and there were no Fuel Injected cars back then. Save the engine wear, go Synthetic!:)
 
Darth-Car said:
Don't be scared of synthetic oils. I have been an Amsoil dealer for years, and have run it in many carb'ed Chrysler's, and Jeeps with Zero problems. What is key here is to use a quality synthetic oil. Mobil 1 is a more low quality product to keep it cost competitive. You can run a quality Synthetic in a carb'ed motor for 20,000 miles with NO issues. Amsoil was developed in the early 70's, and there were no Fuel Injected cars back then. Save the engine wear, go Synthetic!:)
Click to expand...

It's always a debate.
But myself? I won't do it.
 
The only oil or 'snake oil' gimmick I have fallen for, enough I buy it is the 'High Mileage' oil.

Synthetic oil in my 77-89 I own is like talking to Chris Hatfield in person about UFO's.
I'll take his opinion v/s the internet.
 
Darth-Car said:
Don't be scared of synthetic oils. I have been an Amsoil dealer for years, and have run it in many carb'ed Chrysler's, and Jeeps with Zero problems. What is key here is to use a quality synthetic oil. Mobil 1 is a more low quality product to keep it cost competitive. You can run a quality Synthetic in a carb'ed motor for 20,000 miles with NO issues. Amsoil was developed in the early 70's, and there were no Fuel Injected cars back then. Save the engine wear, go Synthetic!:)
Click to expand...
I agree that Amsoil makes excellent products. But there is a risk with any synthetic motor oil slipping past older seals, where conventional oils don't. Can you give additional info about Amsoil not causing oil leaks at seals, but other synthetics being lower quality causing leaks ?
You didn't really mean 20,000 miles ?
 
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