Which oil to use? Which is the thick stuff?!

sudzs

I have a Mazda 626 and the problem is that it puts out tons of smoke when you start it up first thing in the morning. Reckon there's a valve leaking oil into one of the cylinders while the car is just sitting there. After the engine warms up it's fine. Not a puff!

The neighbours don't look too happy to see me getting into the car in the mornings so I've taken to checking there's no-one about when I'm heading off! It IS that bad! :rolleyes:

Anyway, someone suggested putting a thicker oil in (when topping up) so is that the oil with the higher number??? 20w ??? Am I right in thinking high viscosity is the higher number and is thicker? Low viscosity is thinner???

What about the oil they recommend for older engines with high mileage?

Car's to be traded-in in the spring but wondering if there's anything I can do to cut down on the smoke in the meantime (without opening it up or getting a new engine!)

Any advice apreciated!

alias no.9

The first number is the viscosity when cold, in general you need a low number so the oil will get around the engine quickly and start protecting the moving parts. The second number is the viscosity when at running temperature, in general this will need to be higher to give the maximum protection. 10w40 would have been a common standard in the '90's, but many manufacturers have moved to 5w30 and even 0w30. Is it possible one of these could have been used the last time your oil was changed? You will need to do a full oil change to notice any difference. 15w40 is probably the thickest 'cold' oil you'll find in stock anywhere, anything else would probably require a special order.

peasant

I would suspect that this has nothing to do with oil leaking somewhere, but rather that one or two of your glow plugs aren't working properly any more. So while the engine is cold, you're blowing half burned diesel out of one or more cylinders.

Seth Brundle

Further to alias's post have a look through this page: www.carbibles.com/engineoil_bible.html
(this site is a must for any petrolhead!)

sudzs

peasant wrote:

I would suspect that this has nothing to do with oil leaking somewhere, but rather that one or two of your glow plugs aren't working properly any more. So while the engine is cold, you're blowing half burned diesel out of one or more cylinders.

It's petrol!!!

peasant

petrol?

ooops ....

Well ... in that case its just simply FUBAR

Henry Ford III

My old car uses 20w50. Good old multigrade. Engine tolerances were a bit higher in the 1970's.

sudzs

peasant wrote:

petrol?

ooops ....

Well ... in that case its just simply FUBAR

S'pose I should have mentioned that in the first place!

What's FUBAR ?

peasant

F ucked U p B eyond A ll R epair

sudzs

peasant wrote:

F ucked U p B eyond A ll R epair

LOL!

Probably, just want it to keep going 'til Spring without poisoning the neighbours!

Crosshair

You should be looking for Duckhams 20W50, not recommended in modern engine unless engine is oilburner and youve nothing to lose.