Servicing a petrol car

[georgeb]

Strange thing regarding service intervals and I've basically thrown the book away here. I don't do a huge mileage and most of that is either short runs or crawling around in traffic, although I do try to take her out for a bit of a good hot blast on a Sunday morning when possible. So in the 6,000kms I've had the '38, I've changed oil and filter 4 times and it's just starting to run clean, having finally shifted the previous gunk out. I only use branded oils, gawd knows what's in the cheap stuff they sell, and oil tends to run thin here anyway due to the ambient temperature. I also find that with the dust, dirt and pollution, I'm getting only 2,000-2,500kms out of an air filter as well and I've just changed it for the third time.

Plugs and leads I did when I first got it, so now I just pull one of the easier ones to get to at oil change and have a gander. They're quite happy, so no need for a change yet.

So to me, what you do and when you do it depends far more on the vehicles history, how you drive, the type of journeys and the operating environment rather than slavishly following recommended service intervals. I'd rather have the peace of mind for what it costs than a knackered engine, although I appreciate I'm probably operating at one of the more extreme ends of the spectrum.

[taurus]

I like to do preventative maintenance rather than wait for a problem to arise. On my modern dailies the plugs get replaced every 20k (despite the service interval being 50k). The Cavalier will be fine with new plugs every 20k - I ran them back in the day and never had an issue.

I am wary of leaving plugs in for extended intervals because they can and do break up with age and bits of plug dropping into the cylinders isn't the best thing for an engine.

Other service items I do every 10k - except for oil. I replace the oil and filter every 5k. I have used Comma oils for years and never had any problems.

The key thing with oil is the detergents, once they are exhausted crud starts to build up. I had a Z22SE which were notorius for breaking timing chains. At 100k I replaced the chains to be on the safe side. The interior of the engine was immaculate - proof that frequent oil changes are the key to keeping engines healthy.

Burning petrol produces water (which is why you see it dripping from cold exhausts) - on short runs that gets into the oil and over time the water content of the oil can increase. Cars that do long runs get hot enough to evaporate the water out of the oil, on short journeys the water content builds up which is why cars used for short runs need more frequent oil changes.

In extreme cases a round town car that uses no oil which is suddenly used on a long run will seem to use a lot of oil - the owner comes in worried because his oil level suddenly dropped when he went to visit granny over Christmas. What has actually happened is that the engine has got hot enough to evaporate the water in the oil and the level has dropped accordingly.

Good advice to use good quality parts - I ever buy from ECP.

[steveo3002]

people saying i used xx brand oil and it was fine doesnt really help , most older tech engines will keep running on the cheapest dregs but doesnt really mean what you put in was a great buy

you can also read up on semi oils , the barest hint of something synth being added allows them to label it semi

for me , i tried some ecp oil in my vw and the engine sounded rank , next change i put castrol in and its back to sounding fine , make of it what you will

at the end of the day anything clean and fresh will keep it going , if youre driving flat out at high revs all day on a track day then it needs to be good stuff , pottering about in a daily isnt so demanding

[ChasR]

I guess this thread was going to potentially be a can of worms.

People say old stuff doesn't matter but I beg to differ . My Stag used to run a low oil pressure when hot on Unipart oil 20W50. It was OK if it had been recently changed but would be around 10PSi when hot. Going to Valvoline VR1 20W50 had the oil pressure increase to near 20 even if I left the oil in for a year ; towards the end the car did not really come out much winter time hence why the schedule drew out a little. It was not a one off either ; the oil was changed in that car quite a few times with a few different oils (Halfords Classic may have been one, but it did eventually just go onto VR1 .

That is not to say that I go out and buy the priciest oil ; the BMW of mine used to run some cheap Comma stuff, and the Clio tends to run the same or Elf (it's the same price and its what the dealers seem to use) until its last aforementioned 'belt change.

The VR1 was about twice the price of the Unipart stuff @£25/27 but one could argue what did I expect for £12 of oil at a gallon...

[steveo3002]

intresting

so the uni part probably met the spec when brand new but soon afterwards didnt

so hard to know what youre buying though...are you getting top notch stuff or just paying for a label

[taurus]

Dec 28, 2015 9:36:30 GMT steveo3002 said:

people saying i used xx brand oil and it was fine doesnt really help ,

Since the OP is asking about a Cav 1.8 and I ran one of those for nigh on 200k on Comma oils I think mentioning that the brand suits the application does help. You can pay more for sexier named brands if you want to, but the Comma stuff in that engine work very well indeed.

[steveo3002]

yeah fair comment - i was getting at the ones that have tried one can of whatver and its fine , it would have to be something shocking to kill a car over one or two oil changes

commas a trustworthy brand though , i still stand by buying good stuff cheap parts /stuff always bites me in the ass

[Deleted]

Dec 28, 2015 10:10:07 GMT steveo3002 said:

intresting

so the uni part probably met the spec when brand new but soon afterwards didnt

so hard to know what youre buying though...are you getting top notch stuff or just paying for a label

Read the specs on the label?

[skylinedave]

For me if its a old car I'm not bothered by the oil as long as its the correct grade - its all made to similar standards anyway I'm guessing .