I've been told by a mechanic friend of mine that AFTER I've used engine flush I can put in vegetable oil, run engine for a short while then drain. He says that as the veg oil is sticky, it'll help remove more of the gunk that hasn't come out during draining. My car is a T reg Volvo S40 2.0l with 130,000 miles. Any thoughts? Thank you.
I cannot conceive of any benefit that putting vegetable oil in your engine would give you and many drawbacks:
- The viscosity is wrong, you would not get the right lubricating properties for your engine, which could lead to damage
- Vegetable oils do not have the heat tolerance that engine oils do, the smoke point for refined almond oil, which is the highest heat tolerance cooking oil I can think of is 270C, your average vegetable oil is going to be far less than that, closer to 210-220C, both are lower than the temperatures they will face in the engine
- Vegetable oils are organic, so will break down into organic compounds which will then be left in your engine, these may interact with the engine oil you use later and create undesirable byproducts
- Engine oils have detergents and other additives to make it work in your engine, vegetable has none of those
You are talking about flushing your engine, then pouring fat into it. It may get some gunk out but what it will leave behind isn't likely to be any better for your engine.
Cooking oil think again... If you use a flushing fluid on your first flush I suggest you then use a cheap oil and filter, on your second flush run that for 30 min low revs / tick over. Then drain. Then replace with New oil and filter PLUS An ENGINE OIL ADDERTIVE putting the addertive in first. For the older cars remove the sump give it a clean check for sludge swaf etc. New gasket replace. I don’t use a flashing fluid just the 2 oil and filter change