If the cover is already rusty and starting to seep, painting it with a rust-converter or high-temperature protective coating is sometimes used as a temporary measure.

Advantages

1) Slows down corrosion

• Rust converters chemically stabilise the existing rust.
• Prevents further oxidation from moisture and salt.

2) Reduces minor sweating

• A coating can seal microscopic pores.
• May reduce light oil misting or sweating.

3) Low cost, quick fix

• No major dismantling required.
• Can often be done in situ with careful masking.

4) Buys time

• Useful if you’re planning a proper repair later.
• Helps prevent the cover from getting significantly worse.

Disadvantages

1) Not a permanent repair

• If the metal is pitted, oil will eventually find a path through.
• The rust underneath may still progress.

2) Can hide the real condition

• Painted parts can look fine while corrosion continues internally.

3) Heat and oil exposure

Some coatings soften or fail due to:

• Engine heat
• Oil vapour

If the wrong product is used, it may peel or degrade.

4) May complicate future repair

• Paint contamination can make sealing surfaces messy.
• Needs cleaning before proper replacement or resealing.

Is It Dangerous?

Generally not immediately dangerous if:

• The leak is only light sweating or misting.
• Oil level is monitored.
• There is no drip onto exhaust components.

It can become dangerous if:

• The leak becomes a drip or stream.
• Oil reaches hot exhaust parts.
• The cover becomes structurally weakened and fails.

Worst-case scenarios:

• Oil burning smell or smoke.
• Fire risk (rare but possible with heavy leaks).
• Loss of vacuum function affecting brake assist.

Best Practice Approach

Temporary fix (acceptable):

1. Clean the area thoroughly.
2. Remove loose rust.
3. Apply:
   • Rust converter, then
   • High-temperature oil-resistant coating.
4. Proper long-term repair (recommended):
   • Replace tandem pump cover or full unit.
   • Fit new seals.
   • Clean mating surfaces properly.

Practical Recommendation

If it’s just light sweating:

• Painting is a reasonable temporary measure.
• Not dangerous if monitored.

If it’s actively leaking:

• Plan for replacement soon.
• Don’t rely on paint as a fix.