help my engine is making a lot of noise!

[spike4073]

i recently bought a volvo 340 dl automatic because i was impressed with the cvt....it only has 57000 on the clock and was running fine for about 2 weeks now all of a sudden the engine is making loads of noise....sounds like its reving its nuts off whenever i go over 15 mph....i first thought that the low gear hold was stuck on but closer inspection revealed that this was not the case......has anyone heard of or come across a simlar thing before any ideas??
please help!

[pete-d]

Hi there Spike,

Hopefully someone will be along here shortly with some useful advice but it's probably worth trying the good folks on www.volvo300mania.com too. These Volvo forums are great but there's a different specialist 300 people there - some of us use both forums too.

Pete

[Clan]

There could be a number of things causing the same problem . Once you get up to 50 mph it should change up with the aid of the centrifugal weights in the primary unit and rpm reduce is this the case?

The cases with probability first assuming it was working properly before this fault developed ..
1 . Broken air valve head in Vacuum 4 way valve , There are two rubber valves in this , one at each end , if you dismantle and find one broken it can be superglued back on and you will get another year or two of extra useful service from it ..
2 , Accelerator kickdown switch on cabe faulty ..
3 , brake switch stuck on , on master cylinder .
4, Vacuum pipe seals where the 2 pipes enter the centre of the primary unit drum
5 , Primary unit diaphragm hole
6 Tachometric relay faulty near brake servo
7 , Have you had some welding done ? Melted front to rear vacuum pipes inside inner chassis members ..

This is really a specialist job , if there are any people left who can remember how they work ! A DAF specialist would be a good first stop ..

[spike4073]

i dont know what it will do if i take it to 50mph....40 is as high as i have had it since this problem started anything above that and it is screaming its head off ...hard to describe the sound...i would say it dosent sound so much like theres something wrong with it as much as it just sounds like it is going a hell of a lot faster than it is....if you know what i mean....allso i have noticed that since this began too happen i have been unable to start the engine without using the choke...

[Clan]

ahh have a look at vacuum pipes coming from the inlet manifold one could have perished or cracked which would upset the idle of the engine too . Whatever happens to the vacuum overdrive upchange mechanism the revs should go down with mechanical action over 50 mph ...

[shimon340]

hi there

are you anywhere near manchester? I've just met a chap who used to work for Daf and then for volvo and used to train volvo dealers how to service Daf vehicles. Im sure he'll be happy to help!

alternatively, there are some CVT experts on volvo300mania.com but most of those guys frequent these forums too.

Clan, you're based at a volvo dealer so you're in the CVT expert team too!

[Sam Widges]

Hello,have you tried turning it off?

[spike4073]

grrr.... over reving problem is back :S ! ...

ive tested the vacuum valve with wires direct from battery..... its mechanicaly functional,

however following green books ive done some checks and the current to the vacuum valve never moves from the low ratio side to the overdrive side


im thinking that this is a microswitch fault stopping it changing up

at the moment im having to put up with revs around 40000 when traveling at 30mph... not good

ive had belts checked (good)

clutch clearance (good)

4 way vacuum valve seems ok will probably change it to be 100%

microswitch,,,, pretty sure its not working right will change it as soon as i source a replacement..

any ideas what to try next if changing the valve and microswitch makes no difference ??????

[Clan]

tachometric relay by the master cylinder ? you should hear it click when rpm gets near 2000 rpm when you listen under bonnet .

Vacuum leak from the plastic lines which go through the chassis , welding tends to melt them!

The rubber Diaphragm in one side or other of the primary unit drums can perforate .

The seals which seal the rotating union which let air in and out of the drums in the centre of the Primary unit drums can wear .

the vacuum 4 way valve may well click , but the head of the rubber valve inside tends to fall off ! easy to dismantle and bond back with superglue , it gives you another 18 months of life from it ..

Broken diaphragm springs in secondary unit ..

etc etc . there are a LOT of things which can cause your problem ...

[volvomania]

Originally Posted by Clan

the vacuum 4 way valve may well click , but the head of the rubber valve inside tends to fall off ! easy to dismantle and bond back with superglue , it gives you another 18 months of life from it ...

It is actually the vacuum side of the system that you need to check.
Have you already gone through this article yet? http://www.volvo300mania.com/forum-u...hp?f=6&t=12314
It actually describes how to investigate vacuum problems.

Since a couple of years you can get an overhaul kit for the 4 way vacuum valve.
Just have a look at article 3291047-R on http://www.born-built-beauties.eu/ht...n_par.html#CVT