Oiling the Underside

[james.ed]

Hi all,

My car is going to get some attention tomorrow. I'm going for the full wash and metal polish. I was going to take her down to a local place for a steam clean underneath and then paint oil onto the underseal. is there any problem with using old oil that's from an engine change, or should i spend my cash and get some new oil?

Thanks as always

[Matt Tomkins]

no difference in using the old stuff for the underside, but i would be concerned about this approach - oil will get washed off and onto the road - dangerous for other drivers and especially motorcyclists

[Leo]

For what it is worth my 1969 Traveller's underside has been covered in old engine oil since new (re-applied as necessary). It is as good as the day it was made. Never needed any welding repairs. A bit messy when working under the car but well worth the effort

Leo

[chrisryder]

the most rust free bits of my car are where the engine has sprayed oil, where the gearbox has sprayed oil, and where the diff has sprayed oil! having said that, i wouldn't apply it deliberately myself. for the reasons Matt went into!

the only thing i will paint with old oil is my leaf springs as it soaks between the leaves and paint would crack with the flexing.

[Matt Tomkins]

the only thing i will paint with old oil is my leaf springs as it soaks between the leaves and paint would crack with the flexing.

either that or dilute grease with petrol and apply in the same way - it seeps in as you describe and remains flexible as you also describe, but the petrol evaporates off, and it won't leek out - also it'll last longer for the same reason

[MarkyB]

I'd suggest starting with the other side which has probably never had any treatment.
Park it on a plastic sheet, take off the gearbox cover and spray oil into the chassis legs, on a saloon remove the foam rubber bungs and pour some into the chassis legs from there.
Some plastic containers to catch any excess that comes out of the drain holes and Bob should be your relative.
After a day or two I doubt any significant amount will come out, if any at all.

I ride motorbikes, and the scary things are diesel spills, especially on roundabouts.
In the wet that black stripe in the middle of the carriageway where numerous vehicles have shed oil is to be avoided too .

[Budgie]

or see the other thread on here re. waxoiling/dinitrol they,ve got better salt defences and generally better protection properties.

[bmcecosse]

Old oil is cheap - it won't be the most pleasant job in the world.......and it won't do any harm, and maybe some good!

[james.ed]

cheap is good for the student wallet.. can you put oil on the leaf springs. i think i once read that this was the one area not to use oil.. heard a suggestion about brake fluid instead?!

[bmcecosse]

Certainly NOT brake fluid - oil is good.

[Matt Tomkins]

or as i said before - grease thinned with petrol - works better imho

[chickenjohn]

or see the other thread on here re. waxoiling/dinitrol they,ve got better salt defences and generally better protection properties.

I agree, use the proper products for the purpose- underbody and cavity wax are much longer lasting than engine oil and you oly need to apply once every year or two. Old engine oil will need to be applied regularly as it washes off onto the road, causing (as others have said) a safety and environmental hazard.

[james.ed]

right.. compromise has been reached!

I've done the leaf springs and a thin well worked in coat of oil on the wheel arches (those pesky troublesome flat bits that collect water) and i've got some oil on the boot floor (thanks for the tip). boot floor needs some serious grinding and a proper job doing. it'll be on the drive for the next few days so any run off will hit my floor before i hit the road.


I'm on a tight budget and a far tighter time frame at the moment. My moggy was waxoiled last feb and come july i'll be finished with uni forever and have the time to sort out a rewax.. or even better, start stripping the horrid undercoat off and get a good proper paint finish again. as for the internal bits.. they'll have to wait till summer. I'm still trying to get the gearbox cover up.. i've another thread on the stuck screws (today i got another two out.. but the other three are stuck fast and need me to get under the car). when they're out i'll have a go at the box sections.

thanks for the help

[chickenjohn]

Drill out the brass gearbox cover screws and tap the captive threads with a 5/16 BSF tap. new brass screws are available so don't waste time on the old ones!

Or, another idea, heat the heads with a blow torch (remove all carper etc before doing this!, slot the rounded screws with a dremel and get them out with an impact driver.