Is this safe for diesels, specifically the Duramax 6.6L?

Yes..... According to Bars Product, this is compatible with all engines and engine oils.

Can you use this with synthetic oils

Yes, I have used it with synthetic oil with no issues.

What it does with my other gasket that has not have a leak?

If I'm understanding your question correctly.... you would like to know what effect this has on gaskets that are not leaking? The answer is nothing..... Thank you Eric

Is this safe to use with other gas additives such as seafoam, lucas?

Yes there is no problem. This gets poured into your oil crankcase not into your gasoline. Seafoam usually gets poured into your gas tank to clean injectors and cylinder walls sometimes you can put it in the crankcase just about 4 oz to clean junk this does not stop any leaks usually done 100 or 200 mi before an oil change. Lucas has many products some that are injector cleaners that go into the fuel tank some that are oil stabilizers or stop leaks or friction additives that go into your oil crankcase you can have Lucas oil additive/stop leak and bars leak in your oil crankcase they don't interfere with one another

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Bar's Leaks 1040-6PK Rear Main Seal Repair Concentrate - 16.9oz (Pack of 6)

Product ID: 278062424

Details

Brand
Bar's Leaks
Item form
Liquid
Liquid volume
16.9 Fluid
Package information
Bottle
Recommended uses for product
Automotive

🔧Seals multiple leak types

🚗Compatible with all engine oils

🛢️16.9 fl oz per bottle

R5121

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Description

🚗💧 Seal the deal before your engine feels the leak!

MULTI SEAL MASTER - Not just rear main seals—also fixes timing cap seals, cam seals, o-rings, and gaskets.
UNIVERSAL ENGINE ALLY - Works seamlessly with gasoline, diesel, turbocharged, synthetic, and high-mileage oils.
HEAVY DUTY ADDITIVE BOOST - Contains powerful additives that rejuvenate worn seals and crankshafts for lasting protection.
LEAK STOPPER EXTRAORDINAIRE - Restores rear main seals to like-new condition, halting leaks fast.
SIX PACK VALUE CONVENIENCE - Six 16.9 oz bottles ensure you’re always ready to tackle leaks and keep your engine flawless.

Bar's Leaks Rear Main Seal Repair Concentrate is a potent 16.9 oz liquid formula designed to restore and seal rear main leaks caused by wear and seal shrinkage. Compatible with all petroleum-based engine oils—including synthetic and high mileage—it also effectively stops leaks in timing caps, cam seals, o-rings, and gaskets. Packaged in a convenient six-bottle set, it’s the go-to solution for professional-grade leak repair and engine maintenance.

Specifications

ASIN	B00BYS6OD4
Best Sellers Rank	#164,671 in Automotive ( See Top 100 in Automotive ) #455 in Oil & Fluid Additives
Brand Name	Bar's Leaks
Container Type	Bottle
Customer Reviews	4.1 4.1 out of 5 stars (172)
Global Trade Identification Number	10046087010409
Item Form	Liquid
Liquid Volume	16.9 Fluid Ounces
Model Number	1040-6PK
Number of Items	6
Number of Packs	6
Part Number	1040-6PK
Recommended Uses For Product	Automotive
Unit Count	101.4 Milliliters

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Our prices include the product cost, international shipping, import duties, customs clearance, and local delivery charges. We handle all customs and import procedures, ensuring there are no hidden fees upon delivery. PRO members receive additional benefits including free shipping.

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R5121

Duties & taxes included

In stock

Sold byAmazon South AfricaDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to South Africa.

Secure transaction

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TrustScore 4.5 | 7,300+ reviews

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