How much frame rust is too much on my Isuzu Rodeo?

Short answer: Surface rust you can scrape off is normal on an old Rodeo. What matters is rust that flakes in layers or lets a screwdriver poke through, especially at the rear where the suspension links bolt to the frame. Isuzu recalled 1998–2004 Rodeos sold or registered in salt states because rust there can let a rear suspension bracket come loose from the frame, which can affect handling.

Symptom: Flaking, layered rust on the frame rails, holes, rust at the rear suspension mounts, clunks from the rear, or the rear end feeling loose.

What to check first

1. Get under the truck with a flashlight and a screwdriver. Press firmly on rusty spots. If the tip goes through or big flakes come off, that's rot, not surface rust.
2. Focus on the rear frame channels where the suspension attaches. An r/Isuzu owner pointed to those as the weakest areas.
3. Run the VIN at nhtsa.gov/recalls for 10V436 (1998–2002) and 13V547 (2003–2004), and ask an Isuzu or Honda dealer if the inspection was ever done.
4. If you're buying one, ask for photos of the frame before you drive out to see it.

Likely causes

1. Road salt corrosion at the rear suspension lower link brackets. Isuzu's recall says long exposure to road deicing salt can badly corrode the area around the front mounting bracket for the rear suspension lower link.
2. General frame rot from age and salt. r/Isuzu owners with badly rotted frames talked about swapping to a clean frame from a donor truck.
3. Surface rust only. If nothing goes through when you poke it, owners suggest cleaning, rust converter and a rust-encapsulating paint.

What it usually costs

The recall inspection and repair are free on covered trucks if Isuzu still honors them for your truck. Isuzu's owner letter for trucks over 10 years old said the free repair was offered for 12 months after the first letter, and after that owners would pay; it listed parts prices of about $27–$54 for anti-corrosion compound and about $210 or $407 for reinforcement bracket kits, plus labor. For a badly rotted frame, owners on r/Isuzu talked about a donor-frame swap rather than patching.

Is it safe to keep driving?

Not if there's rot at the rear suspension mounts or holes in the frame. A bracket tearing loose can make the truck hard to control. Have it inspected before driving at highway speed. Verify with a mechanic.

DIY or shop?

Inspection is DIY. Structural repair is a shop job (welding and reinforcement brackets). Cleaning and painting surface rust is a good DIY job.

Recalls, bulletins and complaints in plain words

• Recall 10V436 (1998–2002 Rodeo, 2002 Axiom, and 1998–2002 Honda Passport sold or registered in salt-belt states): rust can damage the area around the rear suspension lower link bracket so it detaches from the frame. Dealers inspect, apply anti-corrosion compound, or install a reinforcement bracket; in severe cases Isuzu offered to buy the truck back. If your car is part of this recall, the dealer fixes it for free, but for trucks over 10 years old Isuzu only promised a free repair within 12 months of the owner letter.
• Recall 13V547 (2003–2004 Rodeo and Axiom, and 2003 Rodeo Sport, in salt-belt states): the same rear bracket problem on later trucks, with the same inspect, treat or reinforce remedy.
• Recall 00V058 (1998–1999, separate issue): uneven paint on the rear axle could let the lower link bracket nut loosen. Dealers replace the nut and bolt.
• NHTSA complaints: 607 keyword-matched complaints for Isuzu Rodeo 1998–2004 (of 1,933 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-18; keywords: frame, rust, corros, rotted, rotting, rotten).

What owners report

• In '97 Rodeo frame rust — how much is too much?, a buyer looking at a manual 4x4 Rodeo asked the community to judge frame photos before buying, knowing some Isuzus rot through with big holes.
• In 99 Rodeo frame rot, commenters suggested finding a non-running donor with a clean frame and swapping it, rather than patching a rotten one.
• In Frame rust questions, an owner of a 1994 Rodeo did a screwdriver poke test and nothing broke through. Replies said the rear frame channels where the suspension attaches are the weak spots, and suggested grinding, treating and undercoating.

My take

My advice as a former pre-purchase inspector: on any old body-on-frame SUV from a salt state, the frame is the inspection. Bring a flashlight and a screwdriver, and if the rear suspension mounts are flaking in layers, walk away no matter how nice the interior is.

Vehicle focus: 1998–2004 Isuzu Rodeo; the same bracket recall also covered the Isuzu Axiom and Honda Passport.

Safety / mechanic note

A rear suspension bracket that tears loose can cause a loss of control. Verify with a mechanic.