Help! Bearing noise??

[orangeLP400]

I have a G reg 1990 Eunos 1.6 with only 70K miles...been hearing this bearing type noise sometimes when ticking over and definitly when the revs drop almost to tick over...sounded like alternator or power steering pump bearing to me but when i took a look it seems to be coming from under the cam cover and when i took off the oil filler cap it was much louder. Car is perfect otherwise and oil to level and clean. Advice/help from the MX5 gurus would be appreciated thanks.

[Pete Franklin]

Does it go away when the engine is hot? It sounds like tappets to me.- if so then its a pretty common occurance on older mx5s- best bet would be to try an oil change with a fully synth 0w-40, 5w-40 or 10w-40, i think there are also additives that may help but dont quote me on that.

Pete

[OnlyMX5ives]

As above, if its a tick, tick, tick that rises and falls with revs most likely HLA's.

If you have a reasonable oil in there, try an additive, halfords sell one.

If not (or due a change) try a flush and a decent semi syth.

[BonzoGuinness]

Had this on a low-mileage (5k/year) car that had sat unused for a wee while before I bought it - oil changed to 0W-40 as soon as I bought it, cured the noise for 2000 miles or so, another change but with an engine flush beforehand and regular "italian tuneups", seems to have cured it again - for now!

[orangeLP400]

No this is not a tick tick noise that rises with revs, it is more of a metalic "squreeching" sound, like a dry bearing. Will investigate further next week. Thanks for your responses.

[BonzoGuinness]

Ah - sorry. Is it loud as fk? That would suggest a belt - had to change my alternator belt last week, quite easy to do.

With the clutch engaged and the gearbox in neutral I also get a mouse-quiet squeak - disappears as soon as you touch the clutch pedal though - no idea what that one is...

[orangeLP400]

No, not a fan belt slipping!! its a metallic squreeching, not that loud and can be heard on tickover and when revs drop ...as its louder when oil filer cap off i was wondering about the camshaft bearings or whatever they revolve in! have not taken cam cover off before so dont know what lies beneath but thought i would ask folk on here in case it was a common problem and i could get some direction. Have a manual at work so will investigate next week but all help and suggestions appreciated. Car runs fine, lots of power , starts first time, no other untoward noises. It is filled with standard shell oil, so as per suggestions here i may refill with fully synth.

[MX-5 Lazza]

To see if it's belt noise spray some water on the belts as it's running. If the noise goes away or even changes in pitch then you know where it's coming from.

That clutch squeak is likely to be the release bearing (or is it the thrust bearing?). Mine has been like it for over 3 years. It hasn't got any worse doesn't seem to cause a problem other than a mildly annoying squeak.

ETA: too slow again. Ok, I don't know what the engine squeak is.
ETA again: Water pump?

Edited by MX-5 Lazza on Sunday 6th September 09:54

Edited by MX-5 Lazza on Sunday 6th September 09:55

[OnlyMX5ives]

As Lazza suggests try WD40 to eliminate belts etc.

If not then next suspect would be cambelt pullys (but hard to diagnose without hearing it)

[OllieWinchester]

My water pump screeched a bit when it was on its way out.

[Gizmo!]

First time I drove my MX after its service last week it ticked at me, rising with engine speed, until it was properly warm (a good ten mins' driving). Doesn't seem to be doing it now. Does this mean the new clean oil has now circulated around the HLAs and I don't need to worry about it?

edit: going to Brands for the trackday on Thursday, so I don't want to kill it.

Edited by Gizmo! on Monday 7th September 14:14

[robgee1964]

orangeLP400 said:

No, not a fan belt slipping!! its a metallic squreeching, not that loud and can be heard on tickover and when revs drop ...as its louder when oil filer cap off i was wondering about the camshaft bearings or whatever they revolve in! with standard shell oil, so as per suggestions here i may refill with fully synth.

Mine was making a sort of scraping noise on tick over. It went away when the engine was warm though, turned out to be the water pump. Its hard to imagine the cam bearings making a dry noise, generally wear in that area just makes the whole engine sound sort of clattery and tired.

I only found out what it was by accident, when I changed the cam belt. The water pump bearing was dry, and felt tight to turn. Since replacement and reassembly said strange noise has gone away. You could have a belt tensioner bearing gone dry, although they are less likely to make a noise such as you describe.

Water pump noise would most likely sound louder with the filler cap removed, since the water pump lives inside the timing cover, so is sort of internal to the engine.

As for oil I'm running 10W40 semi synth, the cars got a few miles on and I want to ensure plenty of bottom end protection just in case I decide to thrash it ;-) BTW excessive hydraulic tappet noise, apart from wear and oil blockages can simply be caused by too thin oil.

[orangeLP400]

Thanks all for info...still had no time for further investigation but i think the suggestion that its the water pump would seem to make the most sense noise wise...will check it out and will comment.

[vrsmxtb]

Sorry to resurrect this, but I'm having a very similar odd hollow rumbling kinda noise from somewhere in the engine. It has been stood all winter so I'm guessing perhaps a bearing has got dry and is on its way out. It pitch of it seems fairly unchanged by engine revs, it's definitely nothing clutch gearbox related. The water pump should have been new a couple of years ago, I only say should have as I'm trusting that the garage swopped my then new pump onto my replacement engine, although it is possible this never happened! Anything else ancillary related with a bearing? Alternator? Roller tensioners etc?

[anonymous-user]

There are the tensioner and idler pulleys for the cambelt, but I don't know whether they rumble if they are worn.