Cjkacz

So I just got a 1982 FB RX7. The previous owner had full synthetic oil in it and because it's so thin it leaks a bit through all the seals in the engine. Is my best bet to revert back to conventional oil? Or can I get away with a blend without it leaking?
Any help would be appreciated!
Thanks


Corey

Sgtblue

iTrader: (16)

Synthetic or mineral it doesn't make any difference in leaking. If it leaks with synthetic it will leak with any oil and with any viscosity. Change the gaskets or seals or live with the leaks

cone_crushr

iTrader: (18)

My experience is completely counter to Sgtblue's. I have multiple vehicles that leak with synthetic oil that stop leaking when switched to conventional. Use "high-mileage" oil to gain the benefit of swelling agents for the gaskets.
That said, the only way to determine if your leaks will stop is to change the oil and see. The seals may be too far gone to fix, but it doesn't hurt to try different oil brands before performing a rebuild.

Evil Aviator

Sometimes switching to a thicker oil like 20W-50 will reduce the oil consumption and smoke. Adding Motor Honey usually helps too. It rarely makes a difference whether the oil is conventional, synthetic, or a blend, so if the engine is blowing through a lot of oil then you may as well just use conventional and save some money.

However, ultimately your engine will need a rebuild in order to actually fix the problem, and the faster that is accomplished the better your chances of being able to reuse the expensive hard parts of the engine. New 12A housings are no longer in production, so you really don't want to risk ruining yours if you can help it.

Sgtblue

iTrader: (16)

I misspoke. It should have said synthetic doesn't make any difference in causing leaks.
The detergent properties of synthetic and it's better lubricity may exacerbate leaks, but it doesn't cause them. It's an old car, with a lot of miles. Switching back to traditional oil won't heal worn seals or brittle failing gaskets.

Myths about Synthetic Oils - Is it safe to switch to synthetic motor oil? | HowStuffWorks
Myth #3 ---> Five Common Engine Oil Myths
leaks!...synthetic to conventional at high mileage | Passenger Car Motor Oil (PCMO) - Gasoline Cars/Pickups/Vans/SUVs | Bob Is The Oil Guy

Cjkacz

so theres the kicker. The 1982 only has 39,000 miles on it. So it's not like the engine is worn down at all. Any thoughts?
thanks

corey

misterstyx69

iTrader: (142)

As someone mentioned try the High mileage Castrol or a thick viscosity oil..like 20w-50.
These engines are not happy with that watery 5w30 oil designed for EFI based newer engines..it just doesn't cut it.
I'm not saying you are using that,I'm saying that it loves a good thick oil.

Give it a shot.
You have zero to lose and Happy driving to gain!

Evil Aviator

I guess I should back up and ask what should have been asked from the beginning since you are new to these cars...

What makes you think that the oil leaks a bit through all the seals?

There could be corrosion pitting, old seals that are leaking, bad seal springs, etc. Metal surfaces, seals, and springs wear out with time. The engine will require disassembly to determine the actual problem, assuming there even is a problem based on your answer to the previous question.

Yes, synthetic oil hasn't actually caused leaks since the 1970s. The industry has long since fixed that problem.

Cjkacz

So
1) not sure it's ALL the seals
2) previous owner (based on he's actually correct) Basically said that's the reason it drips.
(He is a "car guy" and owns a 67 Cobra) and is an in law, so I trust his judgment.
But again, I'm new to this. And have heard several different things. I'm changing the oil tomorrow to a conventional 10w30. Currently it has 5w30 in it.

Evil Aviator

OK, that is a problem that will NOT get fixed by changing the oil. Where does it drip from?

Cjkacz

I haven't gotten underneath myself to check it out. So I'm not 100%. I'll know more tomorrow

Sgtblue

iTrader: (16)

v

Cjkacz

Okie dokie! So it appears the engine itself isn't leaking the oil, or the pan or gaskets. It's one of the lines from the engine to the oil cooler. How hard is this to replace?

lduley

iTrader: (1)

If your good with wrenches, hour job maybe, it'll take you longer to find them than replace them lol

misterstyx69

iTrader: (142)

hmm..it soley depends on your wrench..!!
Some people talk a good repair but have no Sockets..!
It's the small guy with the Dirty fingers that can conquer the Big guy with the white over alls!..and the callused internet fingers!
(de-cypher...chuckle!)

If you peek into the 1st gen Specific section you can use some resources to find threads associated with replacing the line.
I am guessing it could be a crush washer or seal on the line.
The difficulty of replacing it is honestly based your ability to do so.If you find out how and then Get at it,then you'll see.

Best of luck to ya..work safe.

KansasCityREPU

iTrader: (9)

I should note that the first gen front mount oil coolers have a tendency to develop cracks in the threaded neck where the lines connect. Some of this is due to owners thinking the connection is loose and they try tightening it. This is a non-no. The hairline cracks can be hard to see. Clean the area well and inspect. Replace the crush washers and hope for the best.

Find the thinnest wrench you can to remove the lines from the oil cooler. I had to take a wrench and grind it down. Harbor Freight has cheap metric wrenches that work good for this.