Originally Posted by rikhav (Post 3591828)

Anybody knows how does this help? Does it help with underbody not catching rust?

Originally Posted by rikhav (Post 3591828)

I gave my car ( fiat Petra) for full servicing at servicing station at a fuel bunk
They do servicing of cars since a very long time

They had cleaned the car very well. The engine bay and underbody was spanking new. AC for some reason cooled rather well after servicing and car felt more responsive (air and fuel filters were changed or cleaned)


They had also sprayed the underbody with used engine oil.

Anybody knows how does this help? Does it help with underbody not catching rust?

I read somewhere else that rubber components of suspension get bloated as they absorb oil and later on crack. How true is this?

Basically does spraying of this used engine oil have any advantages or it's harmful for suspension components?

Originally Posted by rikhav (Post 3591828)

They had also sprayed the underbody with used engine oil.

Anybody knows how does this help? Does it help with underbody not catching rust?

I read somewhere else that rubber components of suspension get bloated as they absorb oil and later on crack. How true is this?

Basically does spraying of this used engine oil have any advantages or it's harmful for suspension components?

Originally Posted by khoj (Post 3592097)

The Ac worked better as the washed condenser rid of various debris and dirt would lead to better heat exchange.

Yes the rubber components will suffer on account of being sprayed with degraded oil.

There is no advantage to be accrued from this archaic practice which only tuns the underbody in to a dirt magnet.

In the past the untreated underbody components and the chassis itself were prone to rusting and this was a quick temporary fix.

Today's vehicles chassis and body shell even for the cheapest ones undergo phosphating, a process the seals the metal against rust and chemical fall out.

Thanks a lot all of you

So effective is this treatment that it renders the need for any sort of underbody coating useless, including the ones offered by the modern car spas and dealerships what to talk about used oil spray.

Originally Posted by adrian (Post 3592184)

We used to spray engine oil mixed with diesel on the underbody of our Ambassador after water service, the main intention being to repel water and reduce the rust build up rate. So far we have not noticed any adverse effects on the rubber parts or the suspension components apart from the fact that they accumulate lots of dust. I also don't feel it is relevant in modern cars with treated panels.
regards adrian

Originally Posted by D C (Post 3591833)

As per various internet sources, this is widely used to prevent rust. It seems to be a short term solution and are mostly used in commercial vehicles / off road vehicles or old generation cars.

Originally Posted by rikhav (Post 3591828)

They had also sprayed the underbody with used engine oil.
Anybody knows how does this help?
I read somewhere else that rubber components of suspension get bloated as they absorb oil and later on crack. How true is this?

Originally Posted by rikhav (Post 3592239)

I will continue with service and tell them strictly not to spray the underbody with oil

Originally Posted by Mr.Boss (Post 3592249)

It's usually Engine oil + Diesel solution. People do believe spraying this solution after water wash should act as a water repellent and prevent from rusting. As explained by other members it will become a dirt magnet instead. Oil + Diesel will make the suspension (rubber) bushes characteristics deteriorate (by making them hard / brittle)

PS: there are possibilities that warranty claim of suspension bushes getting rejected when the trace of oil found on them.


That's a safe bet.

Originally Posted by rikhav (Post 3592301)

No worries about warranty as its ten year old car

Originally Posted by thoma (Post 3592754)

I thought used oil should be disposed with care, now it is being carelessly mixed with dust and next time washed down the drain polluting the environment.

Originally Posted by soumobakshi (Post 3592838)

Yes, its is illegal to dispose Burnt Engine oil this way. And most of the time this will be done by operators and they will also claim that the entire process is illegal.
This is from my experience in Calcutta a while back. Net off this might be OK for non phosphate coated under-bodies but is strictly not required for modern vehicles.