Oil Grade On A Higher Mileage Car

[R34_GT-t]

Hi,

Due to my GT4's 'slightly' noisy engine, I'm thinking of changing the oil to a thicker grade.

I am currently running it on 5w40 Silkolene PRO S fully synthetic with a toyota oil filter which I fitted when I bought it.

Now when cold the car is spot on with the engine noise. It's as quiet as a mouse, but when it warms up fully... the bottom end or top (Can't tell properly) seems to be slightly rattly. It wasn't doing this when I bought it, and has only really came on since I have changed to the silkolene 5w40's.

I have it on good authority that the engine isn't going to explode due to somebody with a well trained ear having a listen, and he said I could try some of the forte or the other stuff which has the PTFE in it (Which I'm not going to use). The chap who had a listen said it seemed to sound like a crank bearing due to it's hollow sound, but then it isn't a loud knock... and it isn't doing it constantly so couldn't be a crank bearing. He said it could be what's been transferred from the spigot bearing or something similar, but the noise seems to be there with the clutch pressed.

The car has done around the 90000ish miles mark or there-abouts, so could I put a thicker oil in it to quieten it down? I was thinking maybe a 10w50's, or something equally similar?

What do other people with higher mileage GT4's run? :)

Cheers, B)

[GT4 BOOSTER]

id assume its a piston bearing / Shell on the way out , if its getting progressively louder as the engine heats up .

you may get away with a new set of shells if the crank isnt too badly scarred , but its not the perfect solution .

try some stp in with the oil its meant to be good.

i also read some horror stories about the ptfe stuff , apparently engine oil cant even stick to it so it creates more damage than good.

i cant see how thicker oil will cure a scored bearing /shell , once damage is done its permanent, all you can do is try to make it less noisey/rattly

shells normally rattle with / at the same speed the engine does whan you rev it. does yours do this ???

good luck in what you decide to do .

[R34_GT-t]

Thanks for the reply. :)

It varies really, as sometimes it does seem louder than others... and sometimes you can't hear it at all in the usual place even after my 45 minute drive home from work... and then sometimes you can.

Another time, I did start the car and had it running a few minutes... revved it up twice to around 5000rpm and let off to check for smoke coming out of the exhaust from cold (Which there wasn't), and it sounded quite loud. On another ocassion, I drove the car home and parked it up when the noise wasn't there. Started it up a few minutes later, and it started doing it loud at idle.

Mine does seem to make the noise at around the same speed as the engine. It does seem to do it at idle but you can only really hear it if you stick your head under the front of the car. Even then sometimes, it seems quieter than others after the same long run. Tonight I got home and did another check on it. It does it at idle, and if you hold the revs steady upto around 1200rpm it will do it. After that, you can't hear the noise at all underneath the car.

The mechanic who did have a look at it did say that it had the same kind of hollow sound as a crank bearing, but he said it doesn't sound like one. He said it could be the spigot bearing, or something similar transmitting the noise down the crank? :) He said that if it was a crank bearing, you would expect to hear it very loud with a rythemetic knock to it which mine doesn't seem to be doing. I'm sure I've heared the same noise on any run of the mill car if you stick your head underneath and keep the revs maintained at fairly low revs... but not 'quite' as loud but not far off. :)

I cut the old oil filter open which came over on it from Japan today. Checked the insides for any sign of metals, and it's clean apart from the colour of the oil which has turned the colour. :)

If it was a bearing Shell getting noisy, could the noise still seem louder and quieter on different ocassions even when the engine has been running for a good 45-50 minutes? :)

Cheers matey. :) I'll try some of the STP stuff, and see if it quietens it down. The mechanic who had a look at it, did say that there isn't really anything to be worried about... so I suppose I must be getting paranoid about the rattles and noises of an ageing engine.

Cheers, B)

Elliot