[Mk2] [NA] Please help

[h3_5xy_j]

Hi, I just started my car for the 1st time since boxing day. I started it on the remote start, went out to it about 8 mins later and there is a horrible, metal on metal, grinding noise . It happens for about a second, intermitantly, making the noise once or twice every 10 seconds.
It seems to be coming from behind the rear passenger wheel, at the bottom of the engine.
I turned the engine off straight away and have called for the AA to come round, but I am hoping somebody here will be able to share some advice on what I can get him to check (sorry I don't know much about engines).
Its a 1990 Rev1 NA, the alternator/clutch/cambelt have all been changed within the last 3 years/-15K and the car is fully seviced etc. Only Mods are 17's and Custom Exhaust (which has been on there for 1.5 years now with no probs.
ANY help appreciated

[Andytoyota]

Is it a grinding or more a knocking noise? Checked oil level recently? Difficult to say without actually hearing the noise, if its something major like big ends then im sure an AA guy would be able to tell you straight away after hearing it.

[h3_5xy_j]

its definately a grinding noise. The oil was checked a few weeks ago as was coolant/tires/lights etc

[h3_5xy_j]

Well the AA bloke came, started the car, shut it off, checked my oil level (wich was fine), scratched his head a bit and said it could be a belt tensioner..... then left
I've topped up my oil now (less than 0.25 of a litre) just to be sure, and its still making the sound
As said, the cambelt/alternator+belt have been changed over a year ago. Could they have gone slack? Is there a guide anywhere on how to check/alter the tension of the belts? I don't even know where the belts are
Anyone help? Please?

[ikarl]

you don't wanna leave yourself stranded but have you tried driving the car if only for a short distance to see if it goes away?

[h3_5xy_j]

I've been tempted, but I wont as I dont want to make things any worse.
I've revved the engine up to around 2k and the noise dissapears, it only seems to happen on tickover (I can only say this as I havent driven it, so it still may happen while driving, but i dont want to find out the hard way)

[si2040]

seems like a belt...if the noise goes away on higher revs can not be really engine related..is it a tick tick tick noise and constant or intermittent.

[h3_5xy_j]

thankyou for your interest and sorry for the late reply....
Its an intermittant grinding noise. At 1st I thought it sounded like metal on metal, but thinking about it now, it could possibly be a belt grinding on metal. The car hasnt moves, so the only moving part is the engine, so it has to be something to do with the engine right?
What's the best way to check the belts? Is there a diagram out there wich shows where the belts/tensioners are located (because I've looked and looked but cant find anything...)
Again, thanks in advance for ABY help you can give...

[Bagaz]

I'd probably be taking off belts now if i was in your position. Obviosly not the cambelt but the alternator belt and air-con belt (if it's fitted to your vehicle). I think it's the next easiest step.
I know your alternator isn't that old but i've heard some nasty sounding noises from them in the past. Even 'freshly' reconditioned ones.

[h3_5xy_j]

any idea how i get to it to check it?

[Bagaz]

Sure just take a spanner to the adjusting bolts to slacken the belt off which will allow you to remove it. Then run the engine and see if the noise has disappeared. It will eliminate the ancilleries at least.
Good luck.

[h3_5xy_j]

I've just found something out. When I put my my foot all the way down on the clutch pedal, the noise stops. As soon as I take my foot off it starts again.
Its not the release bearing, I'm more than familiar with that sound its more of an intemitant grinding noise.
Could this be something to do with gearbox oil? or maybe the clutch is screwed? (shouldnt be, only covered 15k since it was changed 3 years ago).
Is the clutch run by fluid? could it be something to do with that?
ANY help appreciated. I'd love to take her for a drive today if I can...

[Bagaz]

Could be your gearbox oil level or maybe your gearbox input shaft bearings. This is the first shaft that is connected to the engine via the clutch. When the clutch is down, the input shaft stops spinning so no noise. With the clutch up the shaft will spin at the same speed as your engine revs.

[h3_5xy_j]

a friend has said it may be the release/thrust bearing? He said it could've finally broke and thats whats rattling around inside the clutch?
how do I check the gearbox oil? I'll have a look in the knowledge section, but if anyone knows feel free to help out...

[Alteran]

A faulty clutch release bearing would produce more of a rumble rather than a grind. Check your gearbox oil level, like previously mentioned, it sounds more like a gearbox bearing. Input shaft bearing to be precise. The input shaft in the gearbox stops spinning when the clutch is depressed. When an engine is idling, the bearings inside the gearbox dont actually receive any oil from the gearbox, they just rely on the oil thats soaked into them from earlier driving. They only get fresh oil when the car moves and the diff throws oil around the gearbox. (Unless it's a gearbox with an internal oil pump like a Honda S2000). But if your gearbox oil level is very low, the bearings inside may have been starved of oil. If thats the case then i'm afraid the damage is already done. All you can do is top it up but the noise will still be there, albeit quieter.

Hope this helps mate and good luck!

Liam.

[h3_5xy_j]

firstly I just want to thank you for all your help, you're a star!

I'm going to replace the gearbox oil tomorow and see if that makes a difference (thanks to the guide in the knowledge base).

A few questions I have, if you don't mind answering them for me?

I took her for a short spin today, and once the car was on level ground (my driveway is quite steep, and I park with the front of the car at the lower part of the driveway) the noise stopped. The smile on my face was the biggest its been in years
I decided to park her on the drive the other way round (the front of the car at the highest part of the drive) and left her for a few hours. I went out and started her up and guess what, no noise
Does this sound like the oil is too low to you?

If the input shaft bearing has gone, can it be changed easily? or is it a case of getting the box refurbished?

I read somewhere to use MT90 gearbox oil. My car is a 1990 UK N/A and has covered 104k, would you recomend this oil, and would you recomend adding any additives to it?

Once again. Thankyou for your help.

Nick

[RobCrezz]

Got the link to the article about doing the gearbox oil?

[h3_5xy_j]

Got the link to the article about doing the gearbox oil?

http://mr2.noegruts.com/mt-90/mt-90.htm

[Alteran]

Ahh.. it certainly does point to low oil level in the gearbox, especially with the change in gradient. Changing Input shaft bearings are quite complicated. They are press fitted onto the input shaft and only a vast array of presses, pullers and funky tools will change them. So It is really a specialist job to be honest. But if the oil level is low and has starved the internals of oil then other damage may have occured which will only be evident when the gearbox is in bits. I suggest checking or changing your oil and see how you get on. If you have no noises after that, job done. Just keep your ear out in case any weird noises develope in the future. The first tell tale sign that there is a gearbox bearing problem would be unusual noises... If the oil level is ok, try not to leave the engine running too long, stationary, when parked on such a steep hill. The car obviously doesn't like it!

As for the MT90 oil, I have never had any dealings with it really. To be honest the specified oil that Toyota recommend would be more than up to the job. I think people use the MT90 oil because it's thicker (The '90' bit means it's thick as a general rule) and would quieten down a gearbox thats noisy all the time. So i don't see any harm using it in your car I suppose. However, it might give you some notchy gear change issues, especially in the morning (As it's thicker).

Hope this all helps my friend and good luck!

Liam

[h3_5xy_j]

yes it has mate, you've been a great help
thankyou