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Oil change


Tezza7

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I know the conventional wisdom says to run the engine to warm up the old oil before draining but, given that the engine was warm when last used a few days ago and all of the oil will have drained into the sump, albeit for some left coating the oilways, why churn it all up again before draining.

Kind of defeats the object perhaps?

Needless to say the filter will be changed as well *confused*

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I guess one reason is that any small contaminating particles will be suspended in the oil when it is all warmed up and "churned up" as you put it, making it more likely that they will be removed when you drain the oil than if they had settled out in the bottom of the sump in the last bit of oil that you cant quite get out.
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Just be careful though, in my experience (K-Series VVC) hot oil comes out fast when you remove the sump plug even with the filler cap still in place, and you are working around the exhaust which stays hot for quite a while after running. Either don't let it get too hot, or let it cool a bit. Gloves and sleeves may be advisable!
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If you're really anal you can buy some cheap basic oil and, after warming the engine and draining the existing oil, replace with the cheap stuff and run the engine for ten mins, then drain again and replace with good stuff.

 

You have to be pretty dedicated to do this every time though!

 

Edited by - the_village_idiot on 20 Jun 2013 12:05:15

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Quoting the_village_idiot: 
If you're really anal you can buy some cheap basic oil and, after warming the engine and draining the existing oil, replace with the cheap stuff and run the engine for ten mins, then drain again and replace with good stuff.

 

You have to be pretty dedicated to do this every time though!

 

Edited by - the_village_idiot on 20 Jun 2013 12:05:15

 

*thumbup* Drain and flush. Lesson learnt in aviation!

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Quoting Alan Reeves: 
flush with what may I ask and the process.

 

 

Just run up the old oil to temp with cleaning additives, drop the lot, bung in some sacraficial oil to get the last remenants of old stuff out before sticking in the good stuff.

 

Ref "additives" for the car - something like Wynns or Comma. *thumbup*

 

Used to do it on our Lycoming 712/714s if there was any doubt about some of the particles starting to appear in the lubrication system. *wavey*

 

Edited by - Rampmonkey on 20 Jun 2013 12:45:21

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I'm no expert, but I think that there is no need to flush if regular oil changes are being carried out at low mileage intervals, because the small amount of old oil remaining in the engine will be in pretty good condition.

 

Also, if the flush is some cheap oil, I think I would prefer to have some low mileage good quality oil left in the engine than some of the the flushing oil.

 

I always used to warm the oil, but the 5W30 I'm using now runs out cold as fast as the old Castrol GTX mineral oil did when hot *smile*

 

Duncan

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I'm a little obsessive compulsive in my car fettling! 😬

 

I've seen a lot of info out there suggesting that engine flushes are not really needed on modern engines, but a 1994 1.8Vx? Not sure where that sits; hardly cutting edge!

 

I change the oil on my motor EASILY every 500 miles, if not more often. I certainly carry out a drop after each track day. As a result, it tends to come out the same colour it goes in and to date I've never had an engine issue.

 

It may not be completely neccessary but I can't help myself! Rest assured, anyone who buys the 7 off me is getting one that's been, well, serviced! *wink*

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I think it depends a bit on how what kind of mile the oil has done- track miles vs gentle touring miles. Isn't the rule of thumb 1 track mile = 5-10 normal road miles?

 

The engine flushes sound a bit aggressive to me. An engine flush is the stuff that supposedly removes all deposits from the engine and pipe work isn't it? I have read, in older cars, it sometimes does more harm than good as some of the deposits help to seal cracked pipes- there are supposed reports of more oil leaks following an engine flush.

 

The double oil change method I described is a bit OTT but perhaps worth considering if you haven't changed the oil for a while. I wouldn't use a really crap oil though for the reasons already attested.

 

Also the colour of the oil isn't always a good indicator to its condition- oil may look pretty clean still but, if it has been subjected to excess heat and sheering forces, it may be far less effective than it originally was. This is where the really expensive oil comes into its own- retaining it's good properties for far longer and resisting these changes over heat and time.

 

Fuchs ester synthetic all the way for me.

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*arrowup* yeah, fair. Interestingly, the caterham build manual specifically states NOT to use fully synthetic on the Vx OHC engine. As a result I've always stuck to semi, using the recommended Comma oil.

 

Any thoughts anyone?

 

Edited by - Rampmonkey on 21 Jun 2013 09:27:44

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Quoting Rampmonkey: 
*arrowup* yeah, fair. Interestingly, the caterham build manual specifically states NOT to use fully synthetic on the Vx OHC engine. As a result I've always stuck to semi.

 

Any thoughts anyone?

 

That's interesting.

 

Given how often you're changing it I can't imagine it makes much difference. How hot does your oil get?

 

Below is pure speculation, i really dont know what im talking about but....

 

Would imagine consistency is v important. Using semi at somes and fully synthetic at others is probably worse than sticking with the same one.

 

I would also imagine the benefit of fully synthetic over semi is most significant at high revs and high temps. How hot does your oil get and how high does your engine rev? Do you do a lot of track work?

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I haven't an oil temp gauge on the car so I couldn't tell you how hot it gets.

 

In terms of driving, yes it does a fair amount of track time each year. I'd say 50% of its mileage. Road use is an even mix of pootling about and 'enthusiastic' motoring. 😬

 

The Vx 1.8 delivers max power output at 6750 rpm, so if I'm driving enthusiastically it will spend significant portions of time in excess of 4000rpm in anticipation of overtaking etc. Not sure if a previous owner has done anything to the set up (as much as you can with such an engine on Carbs!) but it doesn't like low revs or idling.

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Interesting.

 

If there's any truth to my rule of thumb of 1 track mile being 5-10 road miles then changing the oil after 1 TD (where say you drive 60 laps of a 2 mile circuit) that's 120 track miles = 600-1200 road miles.

 

With decent oil I would suggest changing the oil every 2-3 TDs is perfectly acceptable. That's an oil change every 3000 road miles.

 

Changing every 500 road miles is pretty excessive but if you enjoy doing it and the semi synthetic stuff isn't *that* expensive then fair enough :)

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