cvt noisy?

Post by **spike4073** » 23 Jul 2011 09:24 am

right.... finaly got my 340 1.4 cvt back on the road but when i took it out yesterday for its first proper drive in 2 years i noticed that it seems to have become noisier than it used to be?

it used to be that it was quite loud but when you get it up to speed it got quieter........now it seems that the faster you go the louder it gets...

the noise is best described as a hair dryer on steroids :S i cant figure out if its over reving or if the noise is down to the cvt........ rev counter reads 40 when traveling at around 45/50 mph

anyone know what could be causing this???

Post by **macplaxton** » 23 Jul 2011 08:07 pm

Haven't knockt he low-ratio hold switch on have you?

Post by **spike4073** » 24 Jul 2011 11:11 am

nah that doesnt seem to work.... had the wwitch off and it wasnt hooked up at the back.... ive pluged the wires back in but it dosent make any difference...

ive also checked for vacuum leaks (none) ... also checked the vacuum valve as i beleive these can sometimes fail but all seems good there

cant think what else could be at fault... maybe belt tention?

any idea what the revs should be at when traveling at say 30mph ..... its curently around 35ish on the rev counter seems a bit high to me

i know the engine/carb arent at fault as these were all re-built recently but this loud reving/droning noise is doing my head in ... (darent take it on the motorway)

Post by **Speedy88** » 24 Jul 2011 11:33 am

Does sound quite high yes, I'm no CVT guru but I'd say belt tension is a strong possibility.

Post by **spike4073** » 24 Jul 2011 11:41 am

so would you say that the high revs could be caused by the belts been a bit slack??

Post by **Speedy88** » 24 Jul 2011 11:42 am

Yep, if it's too loose it will slip.

Post by **spike4073** » 24 Jul 2011 11:51 am

hmmm... just need to figure out how to tention them now then lol...

Post by **volvodspec** » 24 Jul 2011 11:54 am

check my post in this topic;
http://www.volvo300mania.com/forum-uk/v ... =9&t=12233

maybe that is of any help to figure out whats wrong

Post by **macplaxton** » 24 Jul 2011 12:10 pm

As well as checking the above, start with the checking/adjustin the belts.

spike4073 wrote:so would you say that the high revs could be caused by the belts been a bit slack??

Yep. One possibility.

Post by **spike4073** » 24 Jul 2011 12:54 pm

have had a quick look at the belts... all seems good tention wise ... have tightened it a little (didnt want to over do it) still no difference?

all electrics are good as far as i know

did just notice however that the plastic shield once removed to access the belts was covered in oil and both the primary and secondary units appear covered in oil and both seem to have small leaks from the drain plugs (will top up soon)

would low gear oil cause exessive noise?

Post by **macplaxton** » 24 Jul 2011 06:30 pm

spike4073 wrote:the belts was covered in oil and both the primary and secondary units appear covered in oil and both seem to have small leaks from the drain plugs (will top up soon)

would low gear oil cause exessive noise?

Oily belts? Can't be doing any favours at all. Best get those leaks seen to first. I've never known oily belts to be particularly grippy...

Post by **spike4073** » 24 Jul 2011 08:15 pm

the belts are dry as a bone oil is just on the plastic guard thingy,

im beginning to suspect the vacuum valve is at fault, i noticed that its fuse in the fuse box was blown so i replaced it (also blew),, then replaced it with a higher spec fuse this didnt blow but seems to have made no difference to running,

so im thinking theres a fault with vacuum valve somewhere, havent found anything on first inspection gromets look good and cant seem to find any obvious electrical issue (will get multimeter out tomorrow)

opened the tachometric thingy,, all good no signs of anything blown or cracked soldering.

i think it may be easier to just replace the vacuum valve and see if anything changes,

also,,, i wanted to check that i had the hoses on the right way around ,,, theres the 2 from the transmission into the valve one slightly larger diameter than the other anyone know which one should go where???

Post by **macplaxton** » 24 Jul 2011 10:52 pm

Off the top of my head no, but if you look in the technical section there is an excellent article on the CVT transmission.

Rather than guessing the tension - measure it. Gap between pulleys should be 1.5 - 2.0mm.

If you measure the width of the belts at their widest point it will give you some idea what the wear is like - new they are 45 - 46mm and can be as low as ~38mm when all the adjustment available is used up.

Good job they aren't oily. Not the cheapest of things to be had...

Post by **spike4073** » 25 Jul 2011 11:17 am

have had tention checked this morning... thats ok aparently

im thinking vacuum valve...... anyone know where i can get a replacement?

Post by **spike4073** » 25 Jul 2011 01:33 pm

deffo the vacuum valve... ive done the checks on it outlined in green book, its dead

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