Is chunky oil buildup a dealbreaker on a used car?
Visible oil buildup and sludge signal potential gasket blowouts and neglected maintenance that can quickly lead to major engine failure. Buyers face the risk of sinking money into a high-mileage vehicle that may already have hidden internal damage, making it difficult to determine a fair price.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Negotiating a lower purchase price to budget for potential repairs
- 2Fixing known engine issues proactively before driving long-term
- 3asking for detailed underside and rocker photos
- 4having someone knowledgeable inspect it before buying
- 5Refusing to buy the vehicle
- 6Inspecting the car with an OBD2 code reader
- 7Testing components like the MAF sensor on-site
- 8Researching potential causes online
- 9Asking mechanics or forums for advice before buying
- 10Searching online to identify what could cause the mechanical symptoms
- 11Trying to roll start the vehicle
- 12Planning to replace the ring gear and starter mounting plate
- 13looking up comparable vehicle prices
- 14hiring a mobile mechanic for an inspection
- 15searching for alternative vehicles with better reliability
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“Looking to buy a boxster and this is tempting. I work on my own cars just nothing this nice lol. The guy is saying it throws the code 22 load signal DME control unit, which I think is what's throwing it into limp mode, correct?”source ↗
“I’m worried about the chunky oil looking build up.”source ↗
“I know these are prone to all sorts of gasket blowouts and was wondering if this was what’s occurring.”source ↗
“Would it be worth driving over and just unplugging the MAF to test, or try cleaning it? If I don't fix it I don't buy it?”source ↗
“The starter rarely makes connection with the flywheel and mounting plate looks bent.”source ↗
“Also, the wipers come on even when the truck is off.”source ↗
“Question is this: is it worth the hassle?”source ↗
“I'm not sure what the owner means. It just says the transmission downshifts weird sometimes but normally shifts fine.”source ↗
“The ring gear is kinda what I was worried about. The starter caught one time while we tested it, but the truck was still in gear. So it didnt actually fire off. After that, it just made angry, grinding noises and I made the guy stop. We tried roll starting it, but had no luck with our short runway.”source ↗
“My main concerns are the rocker rust, age, and whether $6,500 is too much for a 150k-mile example.”source ↗
“What would you guys consider a fair price for this? And is there anything specific I should inspect on a first-gen RAV4 before buying?”source ↗
“Would you personally take this at ~$5k–5.5k if the underside is solid?”source ↗
“My parents are going to look at a 2006 kia Sportage with 130,000 miles. The post says the car shifts fine most of the time, but occasionally the transmission downshifts.”source ↗
“I know nothing about cars and I tried looking up what could cause that and my worry is that means the transmission is failing. I tried to tell my parents that but they don't seem to care.”source ↗
“What would cause a transmission to downshift occasionally but shift fine most of the time?”source ↗
“My parents are going to look at a 2006 kia Sportage with 130,000 miles and an automatic transmission tomorrow. The post says the car shifts fine most of the time, but occasionally the transmission downshifts sometimes when slowing down.”source ↗
“my worry is that means the transmission is failing or it needs something really expensive.”source ↗
“I'm thinking of sending a mobile mechanic out to check it but I really want this vehicle tell me I'm not crazy! I know it's a bit pricey (I'm in Alberta Canada for reference) but a new engine seems like a good deal.”source ↗
Where this came up
People with this problem also raised
- 3Buying a used car when the owner doesn't know the maintenance history
- 2Found damage on a used car after buying it from a dealership
- 6Is used truck frame rust fixable or should I walk away?
- 13Is it safe to keep driving with needle bearings in the transmission pan?
- 12Used car broke down immediately after buying from a dead dealership
- 7How to tell if car suspension bushings need to be replaced