Variomatic cooling air duct

[nomead]

Is the vario cooling duct supposed to have any protection for incoming debris, other than the very rough grille at the bumper (x2) ? I can imagine driving in dusty conditions (dry dirt road) and the vario would then swallow all that abrasive stuff between the pulley and belt. Ouch.

But the problem I'm having is that when driving in wet weather - with heavy rain and puddles on the road - occasionally the vario swallows water from somewhere and the belts start slipping. I really don't know whether it's through the ducts or from under the transmission. All it has done (so far) is that traction pretty much stops for 5-10 seconds and then starts again after the water has dried away from between the CVT pulley/belt surfaces.

Is this normal behaviour, will it cause big trouble sometime in the future, and do I need to start avoiding puddles?

On a slightly related note, when I start the car on a very humid morning (dew/frost), the transmission is very noisy for about 100 meters. Haven't checked but as the previous owner had the belts changed, they're probably Roulunds.

[morgan105]

It's only the rough grilles on the vario for protection but you could fit a fine mesh in to the slots behind the grilles for smaller debris. I wouldn't worry to much about some dust getting in there as the system is pretty robust and basically cleans itself while on the move.

With regards to the belts slipping in the rain, is the plastic rear shield fitted over the transmission/pullies? I've only had them slip like that once when going through a foot deep puddle without the shield fitted but now with the shield back in place I have no more problems in the wet. Make sure it's fitted if you have it.

New drive belts are constructed differently to the old Goodyear type and do have a tendency to be noisy for a while first thing on colder mornings, mine do exactly the same. The only way to stop it is to try and get hold of an original set of belts which had softer sides but they are hard to get hold of now. Newer types are supposed to last longer though but they are noisy in colder weather. I know when mine go again I'm going to see if Goodyear have any that will fit the vario as they still make loads of different V-belts for machinery, ATV's and snowmobiles.

morgan105

[nomead]

Okay, I had a quick look under the car and it seems that the centre portion of the rear shield is missing. There's maybe 20 cm exposed. It's enough so that splashing water can get in between the pulley and belts, so that's very likely the reason for the belt slippage after driving into a puddle. Time to go shopping again, maybe I'll find the whole unit at some breakers.

I'll try to go to a DIY garage soon and have a better look. Mostly because I have a bigger problem now. I mentioned earlier in another thread that the high gear hold isn't working or stuck on. Today I made a quick check under the bonnet - disconnected the two vacuum hoses going to the back of the car and gave them a gentle blow. The larger one reacted as described elsewhere - some air goes in and when I stop blowing, the air comes back out. The smaller hose however... There's a slow leak somewhere because I can (slowly) blow more and more air into it and there's very little that comes back after stopping. I'll need to go under the car and check from the primary, if the leak is still there, then I have a dead diaphragm Wishful thinking, I'm hoping that it's something else (easier to fix), like a perished hose connection.

It will also be a good opportunity to check belt tension (pulley gap), change the oil, etc. maintenance work that the previous owner probably neglected. And naturally check the clutch clearance, although I don't think there's anything wrong with that yet.

I also managed to make a sound clip of the lovely noises my car makes on a wet morning Again cellphone quality, I put the phone on "record" and plopped it in the rear footwell and started the car.

It's uncut so there's a lot of uninteresting time included, but here are the nice bits:
00:06 - Starting the engine, note that it starts right away, and this was on a +2°C very wet morning
00:47 - starting to move slowly forward from the parking place, there's not much room so I can't start accelerating until 01:12
01:15 and 01:21 - whine from the belts? only happens when accelerating with cold belts...
02:28 - 02:35 slowing down to an intersection and taking off again, more belt whine at 02:32

To me it still sounds like there's something horribly wrong with it...

[volvodspec]

is the bigger hose is holding the air, the membrames and the rotating seals in the primairy are ok, the only reason the thin hose can leak air out is because of one of the 3 hoses leak or (more unlikely) the pipework of the thin one in disorder.

when jou pull the thick hose off the emvk if engine is running and you hear air sucking in trough that tube (vacume) it's clear the car stais in low-gear

the cause for this can be found after two tests,
first, disconnect the yellow/green wire of that coil, then the sucking continues, the cause is a faulty valve inside the emvk, if this is the case, you'll need to find an other emvk at the scrapyard or something.

when the yellow/green wire is disconnected, and the vacuum stops the cause is in the electrical system. look for the relais controlling the emvk (mounted on the same bracket as the emvk) dismantle the cover and use a magnifieing glass to look for faulty connections, like tears in the solder.

also check the 3 actuators providing the low-gear function,
the kickdownswitch > pull of yellow/green wire at the throttle pedal and connect it strayt to the vehicle chassis via a loose wire
20bar breakpressure switch > this is found mounted to the head master brake cylinder, 2 wires are connected to this, link the 2 directly together via a loose wire.
low-gear switch > under the gear selector, make sure that the switch is of and when doubting, link the two wires together.

after you've done that, start the engine, and make the modifications as above back to original, one of the 3 mod's will point out the exact problem, the most likely cause is the 20 bar pressure switch, but if you got a rightfout as playfull and heavy as mine, the kickdownswitch is broken

good luck!

[nomead]

also check the 3 actuators providing the low-gear function,
the kickdownswitch > pull of yellow/green wire at the throttle pedal and connect it strayt to the vehicle chassis via a loose wire
20bar breakpressure switch > this is found mounted to the head master brake cylinder, 2 wires are connected to this, link the 2 directly together via a loose wire.
low-gear switch > under the gear selector, make sure that the switch is of and when doubting, link the two wires together.

I checked low-gear / kickdown action by doing this quick test: with the engine ignition on but not running, I switched the low gear hold on, and the green light came on inside the switch. Then I pushed the accelerator pedal all the way and the green light went off again. Now that I think of it, all this ensures is that the kickdown switch is working.

I'll have to investigate further, and thanks for the clear instructions!

[nomead]

Uhhuh... there's something much stranger wrong with the 4-way valve, and I presumably need to find a working one from somewhere. While troubleshooting, I pulled the thick hose off the valve (emvk?) and it doesn't suck. At all. Even though I switch the low gear hold on, it doesn't do anything. I can hear the valve click, though, but it still does nothing. I also checked that engine vacuum is present at the middle port of the valve.

I'll try to do some bench testing on the valve during the weekend, we'll see what's wrong.

I'm just thinking, would it be possible to reverse engineer the 4-way valve and make one out of standard pneumatic valves and stuff?

[volvodspec]

in that case, fuse nr 8 is intact?

the fact that a green light appears at the switch doesn't mean anything, it is way easyer to open the hood, and listen to the kloonk noise when activated, this is the coil on the kickdown side activated.

if you start the engine, remove the thin hose, does this suck (won't suck hard, put your finger on the hole at the emvk to feel if you skin get's sucked in the emvk), when it's ok it will start to suck at 1800+ rpm, when it sucks all the time, there is a problem in the tachorelais.

just wondering, you can hear the valve click, but it doesn't suck?

the thick hose should be on the coil where a green/yellow and a brown wire are present, when the thick hose is present at the coil where there's a green wire with a smaller connector and a brown wire the two are mixed up. mixing up the hoses is often done when a lazy mechanic finds out that the cvt isn't working properly, this kind of work is the most irritating about volvo shops.. they don't even have a dawm clue about how the cvt works.

oh and building a emvk out of other component's is possible, but you need to know that you'll need a 4-3 valve, a flow-restrictor, and a valve that block's the air from one side and let it pass trough the other (dutch word is terugslagklep, don't know the precise english word ) the costs of similar valves is way more expensive than getting another emvk off the scrapyard

[nomead]

All right did some checking again.

Fuse 8 is indeed OK.

The EMVK "thin hose" port does indeed start sucking at around 1800 rpm - didn't measure the rpm but around there.

The "thick hose" side clicks, it gets a voltage across the valve but doesn't suck. And the wires are indeed green/yellow and brown. So there's a blockage inside the EMVK somewhere. I still haven't had the time to do the bench testing on the valve. But maybe there's more spare time during Christmas.

The cost of new pneumatic valves isn't such a problem. I may have something lying around at work, but I think they have 24V coils. Even then, I can probably get new ones at a reasonable cost through my contacts. After that I only need to source / make the restrictor and put things together. The anti-backflow / non-return valve is also not a problem. The only problem seems to be time... or the lack of it.

[volvodspec]

nice job, that the thick hose won't suck but does click is a new one for me, could be that the valve "sticks" so the vacuum won't be passed on.

The anti-backflow / non-return valve

those words will be added to my english dictionary