I'm about to change the plugs for my first time. I'm wondering if the engine should be hot or cold in order to reduce the chance of stripping threads, etc. Thank you.

Cold.

& do not tighten the spark plugs unless you are dead dead dead sure you have not cross threaded them.

(with spark plugs that are difficult to get to as in are well down a tube, put a piece of rubber hose over the top of the spark plug and put in place and thread & start of by hand, before ever putting on the Spark Plug socket.)

Edited 20 March, 20179 yr by Awayoffski

It doesn't matter, cold is safer, simply tighten the plug a fraction before loosening it to break any bond.

Why is cold safer? Do you mean less chance of burning yourself, or safer in terms of the threads?

Edited 20 March, 20179 yr by Wino

As to easy to work, Cold is pretty well understood as not hot, you can lean on the engine, radiator etc, drop a tool, pick it up not burn your self no messing about.

 

Hot can be all sorts of hot from warm to much warmer to that is stupid let the engine cool down.

No harm should really happen (to the car) removing spark plugs and replacing in a still warm engine, but as to a hot engine, then why not just wait and do it easily.

Careless people seem over the years to be able to strip threads even with plugs with easy access even with cold engines.

Edited 20 March, 20179 yr by Awayoffski

Sorry, I should have quoted @sepulchrave as I was asking him.

 

I always do them hot, as usually do them with an oil & filter change so good to have everything up to temp.

 

Heating bolts is always recommended to make them easier to remove so why not spark plugs?

Yes it's more risky changing them hot as you could burn yourself, but there are also lots of other things such as sharp edges and moving parts which cause more of an issue regardless of temp.

 

You dont wait for the over to cool down before removing whats cooking and most people cope ok without burning themselves

^ Pretty much my thinking too.

1 hour ago, clarendon462 said:

I always do them hot, as usually do them with an oil & filter change so good to have everything up to temp.

 

Heating bolts is always recommended to make them easier to remove so why not spark plugs?

Yes it's more risky changing them hot as you could burn yourself, but there are also lots of other things such as sharp edges and moving parts which cause more of an issue regardless of temp.

 

You dont wait for the over to cool down before removing whats cooking and most people cope ok without burning themselves

Makes sense to me, particularly since you'll be using the plug box to remove them so don't have to touch them until they're physically out of the engine.

Loosening them when hot is like heating anything else that needs heat to loosen, spark plugs obviously should not need this.

But anyway some will loosen when, hot or warm, some will remove and put on a cloth, some will juggle hot plugs.

 

So is it 'Simply Clever' to then put the new plugs in and tighten to the correct torque to a hot head?  

Answers on a Post Card or stuck down envelope and dont bother posting.

40 minutes ago, Awayoffski said:

Loosening them when hot is like heating anything else that needs heat to loosen, spark plugs obviously should not need this.

But anyway some will loosen when, hot or warm, some will remove and put on a cloth, some will juggle hot plugs.

 

So is it 'Simply Clever' to then put the new plugs in and tighten to the correct torque to a hot head?  

Answers on a Post Card or stuck down envelope and dont bother posting.

Well, the last time I changed plugs I opened the sump plug to start that draining, then pulled the old plugs. Next I changed the oil filter and checked the throttle and clutch adjustments, then inspected the brakes. Now the oil's finished draining, replace the sump plug, and put the car back in its wheels. Next it's time for a coolant change, radiator flush and new oil. Follow that by checking the tappets, and finally fit the new plugs.

Is it simply clever to think that the engine's cooled down by now?

Now 'they' suck out the oil for H&S, then remove the sump plug and replace etc.

Saves oil all over Gloves or anyplace else...

 

All good stuff this progress and how some people do things, common sense and a clue on maintenance is all that is needed.

 

PS

Checking tappets is such a lovely memory, like changing oil @ 3,000 mile intervals and turning Air Filter Houses to the rear of the engine about October & back in March or April.

Edited 20 March, 20179 yr by Awayoffski

and setting the points

Remember: Don't set them to hard in torque - Nm. A 1/4 after the plug is beginning to biting, is more than enough.

may be some one can tell how much in LBS/inch?

 

To hard the plug will go to cold. To lose it will go to hot and key be loosening...

 

 

 

 

Edited 20 March, 20179 yr by Torbo

58 minutes ago, cheshire_cat said:

and setting the points

 

.....and checking the timing with a stroboscope and a couple of dots of white paint. Oh, and setting the mixture with a Gunsons colourtune

Pinching it up then a quarter turn as Torbo says is the most reliable way to get it right, you only want to crush the sealing washer so it seals, not squash it flat and strip the threads, it's not going to fall out!

 

Cold is safer because juggling hot plugs is painful and stupid and the rubber insert can't grip the plug properly since it goes soft when hot, as usual some of you are overthinking this. There's absolutely no reason for a spark plug to seize if it's been correctly installed in the first place, even on motorcycles with delicate little 10mm plugs I have always done them cold and have only ever needed to repair them when cross-threaded by a muppet.

IMO it should make bugger all difference. Like most people would, I change spark plugs when changing the oil also so the chances are the plugs will be too hot to handle for more than a second or 2. So providing you are using a decent plug socket with the rubber insert that holds the plug, you barely need to touch them anyway.

 

Then to replace, use the extension and socket to screw the plug in before using a torque wrench or ratchet. 

 

3 hours ago, Awayoffski said:

Loosening them when hot is like heating anything else that needs heat to loosen, spark plugs obviously should not need this.

 

 

You obvious have never had to change any sparks plugs on a car that has been neglected, I've probably had to change less than 10 sets of plugs in my life (I'm 27) as I've mainly owned diesels but 2 out of those 10 times I have experienced plugs that have been seized solid. Once on a passat that was so overdue spark plugs it was barely running, and once on a mercedes that I suspect had been steam cleaned at some point in its life before being parked up for a while and so water had been sat on top of the spark plug and allowed corrosion.

 

LOL, obviously not had your experiences, just decades of lovely easy to remove spark plugs, the V8's and V6's i have had were all low mileage well cared for.

So long since a Served my time as a Mechanic that i had forgotten how difficult removing spark plugs from modern cars can be.

Edited 20 March, 20179 yr by Awayoffski

21 minutes ago, Awayoffski said:

LOL, obviously not had your experiences, just decades of lovely easy to remove spark plugs, the V8's and V6's i have had were all low mileage well cared for.

So long since a Served my time as a Mechanic that i had forgotten how difficult removing spark plugs from modern cars can be.

 

Modern cars with that many cylinders are almost a guaranteed ball ache. I did a BMW 335i a few years ago and the wipers and scuttle panel had to come off. Apparently that car had 2 turbos which must of been a ball ache to replace as I didn't even notice any of them while i was servicing it.

Ye OK i am convinced the OP asking about a Fabia needs to pay attention to your experiences of BMW's.

 

PS

Dont want to be cheeky but i have had cars older than you and some that have sat as long as since you left school.

Edited 20 March, 20179 yr by Awayoffski

I am not sure the OP needs to worry about most of this thread now tbh. It really doesn't matter whether they are cold or hot. End of.

Brilliant!  I love this forum.  Thanks guys.

15 hours ago, TMB said:

 

.....and checking the timing with a stroboscope and a couple of dots of white paint. Oh, and setting the mixture with a Gunsons colourtune

TMB reminds me of a person in the Norwegian Volvo Club, who can not tolerate that others skilled in the art and trying every opportunity to fling dirt and wiping the knowledge that many have spent years acquiring. And when the simplicity and envy are allowed to unfold, then it all just laughing ...

Boring that some of us use many years of know-how to help people and give good advice, and then comes the idiots and squeezes important knowledge just as it would be unimportant. They nLast idiot will probably never die, there is an increasing number. 

Hope you TMB sleeps well for a long time! Left hands job, is best for some, i suppose. But keep it for your self!

 

Her is an norwegian gir that waiting for you: Good luck!

Edited 21 March, 20179 yr by Torbo

Torbo, TMB is an absolute star. I think you missed the humour in his post.

The question from Doily vas serious! 

Probably from a person who would try to make things even without much experience from before. SUPPORT Why then make it difficult and unattainable for the person?
But when one does not understand how a spark plug works and should work, and do not realize that it is important to the proper torque, so this was a search to make it simple and make the threshold for turning even as simple as possible, without it would result in broken treads etc.

Had TBM known how many spark plug threads I've repaired the cars where people have changed spark plugs himself, he had enough got floored.

 

If it is simplicity that only should prevail here and that only English "self-styled mechanics" without mechanical depth should be allowed to express their views, so I pull me out...