ZX 1.4i Engine knock

delmonte81 · Post by **delmonte81** » 20 Dec 2004, 22:28

I've recently bought a '96 ZX 1.4i 'Elation'. I took a chance and bought it at auction because it was so cheap and interior/exterior are immaculate, also liked the size and functionality of the vehicle.
Everything seems to work as it should but I do have concerns with the engine. Pulling away in first, when revs get to about 1200 and up to 2000 there is a noise which sound like cross between faint knock and rumble which then seems to disappear as revs increase. Noise appears at these revs as I'm accelerating through the gears. It does not seem to be prominent when revving engine in neutral but rather when its under load and can't hear it when travelling at speed (although it's probably masked by road noise etc.).
I really like the car and the way it handles, but does it sound like I'm in for very expensive trouble in the not too distant future?
Any thoughts appreciated.

jeremy · Post by **jeremy** » 20 Dec 2004, 23:41

Does it make the same noise when hot and cold?
have you had a good look at the engine/gearbox mounts and the driveshafts? Often noises that are present when hot anrn't at cold and some things chatter when not under load but quieten when under load.
jeremy

np · Post by np » 20 Dec 2004, 23:49

Has it got any s/history,when was the engine oil last replaced?I say this as a couple of years ago i got my wife a 1.4 Escort.It had been parked up fpr a couple of years,but once jump started ran nice & sweet.On the journey home,it started to rumble & knock,until it became so bad that it just died.I thought the big ends had gone.But after 5 mins it started again & got it home with it still knocking.
The engine oil was so thick,it took an hour to drain it all.Proberly from sitting for 2 yrs.Gave it a service & ran fine after that,with no probs at all.

delmonte81 · Post by **delmonte81** » 21 Dec 2004, 15:12

It is definitely quieter when cold and more prominent after a run.
Car does have a service history, one of the reasons I decided to buy it - last service at 91k (now done 94k) and the oil looks fairly new.

jeremy · Post by **jeremy** » 21 Dec 2004, 16:56

I suppose you should look at the simpler bits first - a general look for anything loose or touching - especially under load (exhaust?) and then the ancilliaries (alternator, PAS pump) - either remove belt or try and listen using a long screwdriver pressed into your ear.
I assume the oil pressure light doesn't flash or come on at idle and that the idle speed is normal and not high. if this is so then the chances are that the main bearings are ok (if it does come on it doesn't mean the engine is shot either). Big ends would I think tend to sound at idle especially slowly with low oil pressure, piston slap tends to happen cold. Little ends - sound higher in the block.
As the noise appears under load I'd start with the engine mounts and look for touching etc. Also worth having a good look at the driveshafts. - its very easy to suspect the worse and you wouldn't be the first to pay a fortune for a recon engine and find the problem still there!
Jeremy

delmonte81 · Post by **delmonte81** » 21 Dec 2004, 17:23

Ok, thanks for that, I'll have a look at driveshafts and exhaust, maybe I'm worrying unduly and if it does go pop I suppose I have'nt lost so much at this stage. Someone suggested that I should give the engine a good flushing and refill with fully synth which I might try.

jeremy · Post by **jeremy** » 21 Dec 2004, 18:55

I can't see that flushing will do any good if the oil looks clean - after all if there is any dirt there it may be quietening it! I'd just use reasonable quality oil. I did try semi synthetic in my megamileage TD BX and if anything thought it was noisier - so I reverted to ordinary again.
jeremy

bxbodger · Post by **bxbodger** » 21 Dec 2004, 19:40

How much did you pay for it ? -If it was only 2 or 3 hundred I wouldn't bother worrying about it-it may be a major fault, it may be something minor, unless its something obvious and cheap to fix, and you can do the work yourself, then just drive it till it breaks and then go down the auctions for another!!
If it was an auction cheapie its important not to fall into the trap of spending lots of money on it!!!!
My BX was cheap, and hasn't needed a lot of money spending on it so far ( as opposed to time........ ) which is why I still have it.

delmonte81 · Post by **delmonte81** » 21 Dec 2004, 20:42

I paid £400 for it inc 10 months tax and mot. Like I said the car is almost immaculate inside and out so I really don't mind spending a few more bob on it to make sure it keeps going, as I like the ride and practicality of the thing - more comfy than my old cavalier was!

bxbodger · Post by **bxbodger** » 21 Dec 2004, 21:55

Its a tricky one- big ends make an unmistakeably loud metallic knocking, so if nothings loose anywhere, and it occurs under load and is a faint rumble,then you could be looking at a bit of wear in the mains-if the oil light goes out straight away though then its probably o.k. and could go on for a few years yet like this so I wouldn't worry overmuch about it.
The other possibility is a soft engine mount-the mounts twist under torque- give the motor a good heaving around and see if it moves a bit too easily on its mounts-you usually get a bit of vibration when a mount goes as well.