Adding a corrosion inhibitor to a gearbox, hydraulic reservoir or engine sump is only a good idea if the additive stays in solution and leaves the seals alone. Cortec has run those tests for years and publishes the results as reference handouts: one oil compatibility chart covering roughly 80 commercial lubricants against seven VpCI and M-series additives, and four elastomer charts covering cleaners, EcoLine products, oil-based products and water-treatment chemistries. The tables below reproduce every entry from those handouts, grouped the way Cortec groups them. Where SRS stocks a product, its column header links to the listing. Cortec marks every sheet “for reference only; reports available upon request,” and so do we: use the charts to shortlist, then confirm on the current data sheet or with a bench test before you dose a system.
How to read the ratings
- FC x% means the Cortec product was found compatible in that base oil or with that material up to the stated concentration by volume. In the oil chart, that concentration is the maximum tested addition rate of the inhibitor in the oil; in the elastomer charts, it is the concentration of the Cortec product (in water or as supplied) the material was exposed to. FC 100% means the neat product.
- NC means not compatible at the concentrations tested.
- FC* or an asterisk on the product name means compatible but contact Cortec for details; in the oil chart, entries marked “oil mixture” were tested in a blend rather than a single base stock.
- — means not tested. It does not mean incompatible; it means there is no data on that sheet.
- v% is volume percent where Cortec printed it explicitly.
- † marks three Shell hydraulic oils where the printed result sits between the M-530 and M-531 columns in Cortec’s handout. We have placed them under M-530, which matches M-530’s hydraulic and gear oil role; confirm with Cortec before relying on the column.
Two general observations before the tables. VpCI-322 and M-529 were tested on the widest range of conventional mineral gear, turbine and circulating oils, typically at 10 to 20 percent. M-530 and M-531 dominate the synthetic and hydraulic entries, most at 10 percent, with M-531 also carrying the lowest tested rates (2 percent) in several gear and hydraulic oils. M-528 is the one additive tested in polyglycol (Glygoyle-type) fluids where VpCI-322 and M-529 were found not compatible.
Oil compatibility chart (Cortec, updated 7-19-2016)
Products across the top: VpCI-322, VpCI-326, VpCI-329 (the ready-to-use VpCI-329 D is the same chemistry pre-diluted 1:9 in naphthenic oil), M-528, M-529, M-530 and M-531. The newer ashless turbine additive M-535 post-dates this chart and is not included; ask us for its compatibility data.
Castrol
| Base oil | VpCI-322 | VpCI-326 | VpCI-329 | M-528 | M-529 | M-530 | M-531 | Notes |
|---|---|---|---|---|---|---|---|---|
| Alpha SP 200A-F | FC 20% | — | — | — | — | — | — | — |
| Optigear | NC | NC | — | — | FC 5% | — | — | — |
| RX Super Motor Oil SAE 15W-40 | — | — | — | — | FC 5% | — | — | — |
| Alphasyn T 460 | — | — | — | — | FC 5% | — | NC | — |
| Alphasyn EP 460 | — | — | — | — | FC 5% | — | NC | — |
Chevron
| Base oil | VpCI-322 | VpCI-326 | VpCI-329 | M-528 | M-529 | M-530 | M-531 | Notes |
|---|---|---|---|---|---|---|---|---|
| Meropa 320 Gear Oil | — | — | — | — | — | — | FC 2% | — |
| Rando HDZ 32 Hydraulic | — | — | — | — | — | — | FC 2% | — |
| GST 1 | FC 10% | — | — | — | FC 3% | FC 3% | — | — |
| GST 2 | FC 10% | — | — | — | FC 3% | FC 3% | — | — |
| Teresstic GT | FC 10% | — | — | — | FC 3% | FC 3% | — | — |
Shell
| Base oil | VpCI-322 | VpCI-326 | VpCI-329 | M-528 | M-529 | M-530 | M-531 | Notes |
|---|---|---|---|---|---|---|---|---|
| Corena DE | — | — | — | — | — | — | FC 2% | — |
| Morlina 150 | — | — | — | — | — | — | FC 2% | — |
| Omala 150 | — | — | — | — | FC 5% | — | — | — |
| Omala 220 | FC | — | — | — | FC 5% | FC 5%* | — | No concentration given for VpCI-322 |
| Omala G 68 Gear | — | — | — | — | FC 5% | — | — | — |
| Omala S4 GX 220 | FC 10% | FC 10% | — | — | FC 10% | — | — | — |
| Rotella HD T1 SAE 40 | FC 20 v% | — | — | — | — | — | — | — |
| Rotella T | FC 10% | — | — | — | — | — | — | — |
| Rotella T SAE 15W40 | FC 10% | — | — | — | — | — | — | — |
| Spirax S4 CX 50 | FC 10% | FC 10% | NC | — | FC 10% | FC 10% | FC 10% | — |
| Tellus 46 | — | — | — | — | — | FC 15%† | — | — |
| Tellus Arctic S4 VX32 | — | — | — | — | — | FC 15%† | — | — |
| Tellus S2 M32 | — | — | — | — | — | FC 15%† | — | — |
| Tellus S3 M100 | — | — | — | — | FC 5% | — | — | — |
| Tellus T68 | — | — | — | — | FC 5% | — | — | — |
| Turbo T32 | FC 10% | 10% | NC | — | FC 10% | FC 10% | FC 10% | VpCI-326 printed as 10% without FC |
Mobil
| Base oil | VpCI-322 | VpCI-326 | VpCI-329 | M-528 | M-529 | M-530 | M-531 | Notes |
|---|---|---|---|---|---|---|---|---|
| Mobil ATF 220 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil Delvac 1 SHC 5W-40 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil DTE 10 Excel 32 | — | — | — | — | — | FC 10%; NC at 15% | FC 10% | — |
| Mobil DTE 10 Excel 46 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil DTE 10 Excel 68 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil DTE 25 | FC 10% | — | — | — | FC 10% | — | — | — |
| Mobil DTE 26 | FC 10% | — | — | — | FC 10% | — | — | — |
| Mobil DTE AA | FC 10% | — | — | — | FC 10% | — | — | — |
| Mobil DTE Light | FC 10% | — | — | — | FC 10% | — | — | — |
| Mobil EAL Arctic | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil Gear 630 | FC 10% | — | — | — | FC 10% | — | — | — |
| Mobil Gear 634 | FC 10% | — | — | — | FC 10% | — | — | — |
| Mobil Gargoyle Arctic Oil 226E | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil Gargoyle Arctic Oil 300 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil Glygoyle | — | — | — | FC 5% | NC | — | NC | — |
| Mobil Glygoyle 22 | NC | — | — | FC 10% | NC | — | — | — |
| Mobil Glygoyle 30 | NC | — | — | FC 10% | NC | — | — | — |
| Mobil Glygoyle 320 | NC | — | — | FC 10% | NC | — | — | — |
| Mobil Rarus 427 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil Rarus SHC 1025 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil SHC 525 | FC 15% | — | — | — | — | — | FC 15% | — |
| Mobil SHC 526 | — | — | — | — | — | — | FC 5% | — |
| Mobil SHC 624 | FC 15% | — | — | — | — | — | FC 15% | — |
| Mobil SHC 629 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobil SHC 630 | — | — | — | — | — | FC 10% | NC | — |
| Mobil SHC 632 | FC 10% | — | — | — | FC 10% | FC 10% | NC | — |
| Mobil SHC 824 | — | — | — | — | — | — | — | Listed; no result printed |
| Mobil Teresstic T-32 100 | — | — | — | — | FC 5% | — | — | — |
| Mobilfluid 424 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilgard 412 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilgear 600 XP 68 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilgear 600 XP 150 | FC 20 v% | — | — | — | — | FC 10% | FC 10% | Listed twice in the source; VpCI-322 result appears on one of the two lines |
| Mobilgear 600 XP 220 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilgear 600 XP 460 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilgear SHC XMP 150 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilube HD 85W-140 | — | — | — | — | — | FC 10% | FC 10% | — |
| Mobilube S 80W-90 | — | — | — | — | — | FC 10% | FC 10% | — |
Other oils tested
| Base oil | VpCI-322 | VpCI-326 | VpCI-329 | M-528 | M-529 | M-530 | M-531 | Notes |
|---|---|---|---|---|---|---|---|---|
| Terresolve Envirologic 215 | FC 20 v% | — | — | — | — | — | — | — |
| Royco 889 | — | — | — | FC 5% | — | — | — | — |
| Summit NGL-777 | — | — | — | FC 5% | NC | — | NC | — |
| Summit PGI-100 | — | — | — | NC | NC | — | FC 5% | — |
| Summit PGS-2 | — | — | — | FC 5% | NC | — | NC | — |
| Milmax 46 Hydraulic Oil | — | — | — | — | — | — | FC 2% | — |
| Stilmoil ABACUS 46 O.C. | — | — | — | — | FC 5% | — | — | — |
| Chryso oil | — | — | — | — | FC | — | — | No concentration given |
| Houghton-Safe 273 CTF | — | — | — | FC 10% | — | NC | NC | — |
| Houghton Stack Magic Eco-f V2 | — | — | — | FC 10% | — | NC | NC | — |
| Loctite 598* | FC 15% | — | — | — | FC 15% | — | FC 15% | Oil mixture |
| Loctite 565* | FC 15% | — | — | — | FC 15% | — | FC 15% | Oil mixture |
| Loctite 515* | FC 15% | — | — | — | FC 15% | — | FC 15% | Oil mixture |
| Parker O-Lube 884-4* | FC 15% | — | — | — | FC 15% | — | FC 15% | Oil mixture |
| Whitmore Paragon 1500 Gear Oil | FC 15% | — | — | — | — | — | FC 15% | — |
Elastomer compatibility: cleaners and rust removers
These are the materials you find in dip-tank liners, pump seals, spray-washer hoses and the gaskets on the parts themselves. FC 100% means the material tolerated the neat product; VpCI-416 was tested at its working dilution of 33 percent. Note the nitrile result for VpCI-414 and VpCI-422: if your parts washer has Buna N seals, pick a different cleaner or plan on a seal change.
| Material | VpCI-414 | VpCI-415 | VpCI-416 | VpCI-418L | VpCI-418LM | VpCI-422 | VpCI-423 |
|---|---|---|---|---|---|---|---|
| Nitrile (Buna N / NBR) | NC | — | FC 33% | — | — | NC | — |
| EPDM | FC 100% | — | FC 33% | — | — | FC 100% | — |
| Viton (FKM) | FC 100% | — | FC 33% | — | FC 10% | FC 100% | — |
| PTFE | FC 100% | — | — | — | — | FC 100% | — |
| Neoprene | FC 100% | NC | FC 100% | NC | — | — | FC 100% |
| Polypropylene | FC 100% | — | — | — | — | — | — |
| Nylon (oriented polyamide, OPA) | FC 100% | — | — | — | — | FC 100% | FC 100% |
| PET / PETE | FC 100% | — | — | — | — | FC 100% | FC 100% |
| Acetal (POM) | FC 100% | — | — | — | — | FC 100% | FC 100% |
| Fiberglass | FC 100% | — | — | — | — | FC 100% | FC 100% |
Elastomer compatibility: EcoLine and other products
EcoLine products are soybean or canola derived, and their behavior with rubber is not the same as a mineral oil. The standouts are EcoLine 3220, compatible with every material tested at full strength, and EcoLine LT rust preventative, which is not compatible with nitrile, EPDM, silicone, neoprene, butyl or polypropylene and should be kept to PTFE-contact equipment.
| Material | Corwipe 300 | CorrLube Food Grade Penetrant | EcoLine Cleaner/Degreaser | EcoLine Cutting Fluid | EcoLine Lubricant | EcoLine LT RP | EcoLine Pump Protector | EcoLine 3220 | MCI-2022 |
|---|---|---|---|---|---|---|---|---|---|
| Nitrile (Buna N / NBR) | — | — | — | — | — | NC | — | FC 100% | — |
| EPDM | — | — | — | — | — | NC | — | FC* 100% | — |
| Natural rubber | — | — | — | — | — | — | — | — | FC 100% |
| Viton (FKM) | FC 100% | — | NC | — | FC 100% | — | — | FC 100% | — |
| Silicone | FC 100% | — | — | — | — | NC | — | FC 100% | — |
| PTFE | FC 100% | — | — | — | — | FC 100% | — | FC 100% | — |
| Neoprene | — | — | — | — | — | NC | — | FC 100% | — |
| Butyl | — | — | NC | — | — | NC | — | FC 100% | — |
| Polypropylene | — | FC 100% | NC | FC 100% | FC 100% | NC | FC 100% | FC 100% | — |
| Nylon (OPA) | — | FC 100% | — | FC 100% | FC 100% | — | FC 100% | FC 100% | — |
| PET / PETE | — | FC 100% | — | FC 100% | FC 100% | — | FC 100% | FC 100% | — |
| Acetal (POM) | — | FC 100% | — | FC 100% | FC 100% | — | FC 100% | FC 100% | — |
| Fiberglass | — | — | — | FC 100% | — | — | — | FC 100% | — |
Elastomer compatibility: oil additives and oil-based products
This is the table to check alongside the oil chart above. VpCI-329 is the most fully characterized: compatible with nitrile (with a Cortec consultation flag), PTFE and neoprene at full strength, not compatible with EPDM, silicone, butyl or polypropylene. The M-series additives were tested at their intended dose range of 5 to 10 percent, not neat.
| Material | M-529 | M-530 | M-531 | VpCI-238 | VpCI-239 | VpCI-322 | VpCI-329 | VpCI-369 |
|---|---|---|---|---|---|---|---|---|
| Nitrile (Buna N / NBR) | FC* 5% | NC | FC 10% | — | — | FC 100% | FC* 100% | — |
| EPDM | — | — | — | — | — | — | NC | — |
| Viton (FKM) | FC 10% | FC 10% | FC 10% | — | — | — | — | FC 10% |
| Silicone | — | — | — | — | — | — | NC | — |
| PTFE | FC 10% | FC 10% | FC 10% | — | — | — | FC 100% | — |
| Neoprene | — | — | — | — | — | FC 100% | FC 100% | — |
| Butyl | — | — | — | — | — | — | NC | — |
| Polypropylene | — | — | — | — | — | — | NC | — |
| Noryl (PPE/PS blend) | — | — | — | FC 100% | FC 100% | — | — | — |
Elastomer compatibility: water treatment and process products
Concentrations here are low because these products are dosed at fractions of a percent in hydrotest water, closed loops and cooling systems. VpCI-649 was tested at its working range (0.5 to 1 percent); VpCI-337 and VpCI-377 were tested up to neat because they are sprayed and fogged as supplied.
| Material | M-370 | M-435 | M-528 | M-640L | S-69P | VpCI-609 | VpCI-611 | VpCI-637 GLE | VpCI-649 | VpCI-337 | VpCI-377 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Nitrile (Buna N / NBR) | FC 20% | FC 2% | FC 10% | FC 3% | FC 0.2% | FC 10% | — | NC | FC 1% | FC 100% | FC 20% |
| HNBR | — | — | — | — | — | — | — | — | — | FC 100% | — |
| EPDM | FC* 10% | FC 2% | — | FC 3% | FC 0.2% | — | — | — | FC 0.5% | FC 100% | FC* 10% |
| Natural rubber | — | FC 2% | — | FC 3% | FC 0.2% | — | — | FC* 100% | FC 0.5% | FC 100% | — |
| Viton (FKM) | FC | — | FC 10% | FC 3% | — | FC 10% | — | NC | FC 0.5% | FC 100% | FC 20% |
| Silicone | FC* 10% | — | — | FC 3% | — | — | — | — | FC 0.5% | — | FC* 10% |
| Fluorosilicone | — | — | — | — | — | — | — | — | FC 0.5% | — | — |
| PTFE | FC* 10% | — | FC 10% | — | — | — | — | — | FC 0.5% | FC 100% | FC 50% |
| Neoprene | FC* 10% | — | — | — | — | — | FC 100% | FC 100% | FC 0.5% | — | FC* 10% |
| Butyl | FC* 10% | — | — | — | — | — | — | — | — | — | FC* 10% |
| Polypropylene | FC 100% | — | — | — | — | — | — | — | FC 0.5% | FC 100% | FC 100% |
| Nylon (OPA) | FC 100% | — | — | — | — | — | — | — | FC 0.5% | FC 100% | FC 100% |
| PET / PETE | FC 100% | — | — | — | — | — | — | — | — | FC 100% | FC 100% |
| Polyurethane | — | — | — | — | — | — | — | — | — | FC* 100% | — |
| Acetal (POM) | FC 100% | — | — | — | — | — | — | — | — | FC 100% | FC 100% |
| Fiberglass | FC 100% | — | — | — | — | — | — | — | — | FC 100% | FC 100% |
| PVC | — | — | — | — | — | — | — | — | FC 0.5% | FC 20% | — |
| PEEK | — | — | — | — | — | — | — | — | FC 0.5% | — | — |
| TFE/P (Aflas) | — | — | — | — | — | — | — | — | — | FC 100% | — |
| Kalrez (FFKM) | — | — | — | — | — | — | — | — | — | FC 100% | — |
| Acetal Delrin | — | — | — | — | — | — | — | — | FC 0.5% | — | — |
How to run your own compatibility check
Cortec’s handouts report results; they do not publish the test method, and the underlying reports are available from Cortec on request. The following is Solvent Recycling Systems’ practical guidance for a shop-level screen when your oil or elastomer is not on the chart. It is not a Cortec procedure and it does not replace a Cortec Laboratories report.
Oil blend screen
- Blend the Cortec additive into a sample of your actual system oil (taken from the machine, not a fresh drum, so it carries the in-service additive package) at the treat rate you intend to use, and at one step higher. For VpCI-322 or VpCI-329 that is usually 5 to 10 percent; for the M-series, follow the data sheet.
- Mix thoroughly in a clear glass jar, cap it, and set it beside an untreated control at room temperature.
- Inspect at 1 hour, 24 hours and 7 days for haze, phase separation, sediment or color change relative to the control.
- If the system sees cold, put a second jar through a freeze-thaw cycle (overnight at the lowest expected temperature, then back to room temperature) and inspect again.
- Any separation or persistent haze means stop and ask; a clear, stable blend is a reasonable basis to proceed at that rate with normal oil monitoring (viscosity, acid number, water) at the next scheduled sample.
Elastomer immersion screen
- Obtain a spare seal, O-ring or a coupon of the actual material. Weigh it and measure a dimension.
- Immerse it fully in the Cortec product at the working concentration, in a sealed container, for 7 days at the highest temperature the equipment normally reaches.
- Remove, blot dry, and re-weigh and re-measure. Flex it and compare hardness by feel to an unexposed sample.
- Significant swelling, shrinkage, softening, embrittlement or surface tackiness means the pairing is not suitable. Minor weight change with no change in feel is typical of a compatible pairing.
Once the additive is in, keep the rest of the program honest: for the water-based products, the refractometer and pH concentration testing guide covers how to confirm the dose in the tank, and the VpCI product selection guide tells you which product is rated for your metal and exposure in the first place. Coating-over-additive questions (for example, whether a residual oil film needs to come off before a VpCI-386 topcoat) are covered in the coatings application guides, and the fuel, oil and hydraulic void treatments used before wrapping equipment are in the MilCorr shrink-wrap guide.
Frequently asked questions
Is VpCI-329 compatible with my gear oil?
On Cortec’s 2016 chart VpCI-329 itself is listed only against Shell Spirax S4 CX 50 and Shell Turbo T32, both not compatible. Its sister products carry the gear-oil data: VpCI-322 is compatible at 10 percent in Mobil Gear 630 and 634 and at 15 to 20 percent in several others, and M-530 and M-531 are compatible at 10 percent across the Mobilgear 600 XP and SHC XMP series. If you want the vapor-phase behavior of VpCI-329 in a gearbox running an oil not on the chart, run the blend screen above or ask us to request Cortec’s report.
What concentration of VpCI-322 should I add to a hydraulic or circulating oil?
Most VpCI-322 entries on the chart were tested and found compatible at 10 percent (Mobil DTE 25, 26, AA and Light; Chevron GST 1 and 2; Shell Rotella T), with a few at 15 to 20 percent. The chart records the compatibility ceiling, not a dosing recommendation; follow the product data sheet for the protective dose, which is often lower.
Which Cortec oil additive works in polyglycol (PAG) lubricants?
M-528. It is compatible at 5 to 10 percent in the Mobil Glygoyle series and at 5 percent in Summit NGL-777 and PGS-2, where VpCI-322 and M-529 are listed as not compatible. M-528 is not currently a stocked item at SRS; contact us to source it.
Are Cortec cleaners safe for the seals in my parts washer?
It depends on the seal material. VpCI-414 and VpCI-422 are not compatible with nitrile (Buna N) but are compatible with EPDM, Viton, PTFE, polypropylene, nylon, PET, acetal and fiberglass at full strength. VpCI-416 is compatible with nitrile, EPDM and Viton at its 33 percent working dilution and with neoprene neat. VpCI-415 and VpCI-418L are not compatible with neoprene. VpCI-418LM has only one published entry (Viton, compatible at 10 percent), so treat it as untested on other materials rather than cleared. When in doubt, run the immersion screen on a spare seal before you fill the machine.
Can I fog VpCI-337 into a system with rubber hoses and gaskets?
VpCI-337 has the cleanest elastomer record on the water-treatment chart: compatible at 100 percent with nitrile, HNBR, EPDM, natural rubber, Viton, PTFE, polypropylene, nylon, PET, acetal, fiberglass, Aflas and Kalrez, with a Cortec consultation flag on polyurethane and a 20 percent limit on PVC. That is one reason it is the default fogging fluid for pipe, tank and heat exchanger lay-up.
Why does the chart show a dash for my oil and product?
A dash means Cortec did not test that pairing when the sheet was compiled, not that it failed. The oil chart was last updated in July 2016 and new oils have been introduced since. Cortec will often have unpublished data or can run the test; contact us with the oil name and grade and we will ask.
Does compatible mean the additive will not change the oil’s properties?
Compatible on these charts means no separation, haze or precipitation was observed at the stated concentration. It does not certify viscosity, oxidation stability or OEM warranty status. For critical systems, sample the oil after dosing and again at the next scheduled interval and compare against the untreated baseline.
Not sure your oil or seal material is covered, or need the underlying Cortec report? Send us the oil name and grade, the elastomer, and the equipment, and we will confirm compatibility with Cortec before you order. Contact Solvent Recycling Systems. The complete range of oil additives and rust preventatives is in the rust prevention category and the Cortec category; cleaners are in the cleaners and degreasers category.
Data source: compiled from Cortec application guides and technical literature (oil compatibility handout dated 7-19-2016; elastomer compatibility handouts of the same vintage); confirm against the current product data sheet before specifying.