knocking sound

[secretreeve]

81k which ain't too bad for a 2006. Engine mounts are definitely shot though, when just starting and stopping the engine it moves ALOT, like so much that you ain't gotta be a genius to see they are gone, also when keeping the brake on putting it in gear and letting off the clutch there's alot of movement as well, excessive amounts of movement

 

[secretreeve]

Btw, what's recommended tyre pressure for 19" low profile xl tyres? It's a 5 door hatch back

 

[Rx7145]

The recommended tire pressure should be on the sidewall of the tire.

 

[oilhammer]

The recommended tire pressure should be on the sidewall of the tire.

It most certainly is NOT. That is the MAXIMUM pressure for THAT tire. How would the tires know what kind of car they are on???

 

[secretreeve]

Well apparently maximum psi is 49. There's a garage around the corner, think I'll ask them lol. They fitted a new tyre for me last week so they should know lol

 

[Jr mason]

If the load rating is close to the OE tires load rating you'd be reasonably safe to use VW recommended pressures. It would at least get you in the ballpark. Again, IF.
The correct way is to have the car weighed and go by the tire manufacturers recommended load charts. There is also a formula that I'm trying to remember.

Vehicle weight ÷4 gets you the load each tire will see.

Divide that by your tires maximum load rating.

Multiply by your tires maximum rated tire pressure.

Using my Jetta as an example. Numbers are approximate - going by memory here.


Car weight - 3200 lbs ÷ 4 = 800 lbs per tire

800÷1355lbs (max tire capacity) = .59

.59 x 51psi (max tire pressure) = 30 psi


My door chart actually calls for 32psi so my vehicle weight is likely off. But it's close. Should get you in the ballpark.

 

[secretreeve]

damn thats one explanation. thanks.

so the blowing sound i think i tracked it down, it picks up when approaching 2k RPM and dies off when dropping below it, now if im not mistaken, thats the turbo spool up point right? so the blowing sound is likely to be something related to the turbo?

 

[Rx7145]

Have you checked the flapper valve in the EGR cooler?

 

[secretreeve]

i have not. a quick google to see what it looks like and all i see is people saying "delete it/blank it" but now i know what it looks like.

 

[Rx7145]

First picture in this thread: https://www.myturbodiesel.com/threa...eak-shutter-sudden-gain-of-boost-thing.21552/

 

[turbodieseldyke]

Car weight - 3200 lbs ÷ 4 = 800 lbs per tire

Weight will be higher in the front, unless the trunk is loaded with fat hookers.

 

[Jr mason]

Weight will be higher in the front, unless the trunk is loaded with fat hookers.

While I do agree, VW doesn't feel its enough to provide front/rear pressures any longer.

In the case of something like a truck that is actually used as a truck it becomes a whole lot more important to get individual axles weighed. But then again, trucks will have recomended front and rear pressures listed.


Edit: I was Going by memory again and it bit me

My 2012 does indeed have front/rear pressures listed but they are the same, 33psi front and rear.
So at least in the case of a 2012 Jetta the weight bias isn't enough for VW to be concerned about, and doing the calculation as above x4 tires rather than individual axles will get you pretty close.

 

[secretreeve]

Well I found the cause of the excessive smoke coming from the bonnet. How I didn't notice I will never understand. A small hose coming out the top of the engine block into the air hose at the back had come off. Popped it back on and no more smoke lmao. Looked like an exhaust gas return hose of some kind.

 

[secretreeve]

new engine mounts arrive tomorrow. looking forward to installing them. though im assuming alignment and tracking will need doing afterwards

 

[Rx7145]

There’s a floor jack method where you push the bushings into the subframe using the floor jack. I haven’t tried it, but I don’t see why it wouldn’t work.

 

[secretreeve]

the whole mounts are getting changed out so it should be a case of unbolting old ones and bolting new ones on, the trolley jack is to brace up the engine and take the weight of it off the mounts. i have a 3rd scissor jack but that will be a pain in the butt to use for this perpous.

 

[secretreeve]

okay, so i installed the new engine mounts, but the knocking is still present. it sounds rotary, deep in the engine towards the rear any ideas what it could be?

the sound is when maintaining a steady speed, you turn, accelerate or break (apply force to the engine) the noise stops, not present at idle, increases in speed with speed, not RPM dependant.

also, whats this part? ok so EGR cooler. cool. needs a new one.
https://ibb.co/KsNMJ5G

one of the mount lugs on it has snapped and its currently help in place by cable ties on one end. worth blanking/removing EGR? how does this affect emmisions for MOT?

 

[kweisel]

Ok, well here's my $.02
If it is not RPM dependent, meaning it does not become louder or more repetitive with engine speed. Its not related to things moving inside the engine. (Crank, top end gearing, or powered accessories)
You state it is speed dependent, so the sound does increase in frequency and/or volume. It sounds (no puns) like something with the transmission or trans axle.
I was supporting and hoping it was motor mount related. Though torque steer is not something I know about very well.
Because the transmission has various moving parts at all different RPMs, it would seem less related to internals. Also would not influence the above torque issue.
I'm leaning towards a discrepancy with the CV joints themselves (dry bearing cavity, loose mounting parts), tangentially perhaps a hub issue too? The torque setting to install the CV axle into the hub is ridiculously high, so noise could transfer towards the engine area? Although I am not sure if you already looked at all that in previous moments?

 

[secretreeve]

i took a look at the CV boots and they appeared to be in good condition, that said i didnt look overly closely because i was fighting that bolt that fixes the dog bone to the chassis. im going to jack it up again tomorrow and get back underneath so i can take a look at the EGR cooler as its seems to be held in place with a singular bolt on one end and cable ties on the other. so i want to see how f*cked up that is. going to replace it with a second hand one. but it allows me the oppertunity to get under the car again and examine the CV boots, control arm bearings and the like. i will also check those axle bolts too. havent got a torque wrench which makes it a little harder but generally speaking im a good gauge for bolt tightness

i was also thinking it wouldnt be topend/internal issues due to being speed dependant and not RPM. it doesnt exactly get louder, just faster as you increase speeds. though when listening to it it does sound like its coming from the EGR cooler area but nothing rotates up there so god only knows lol

 

[kweisel]

i took a look at the CV boots and they appeared to be in good condition, that said i didnt look overly closely because i was fighting that bolt that fixes the dog bone to the chassis. im going to jack it up again tomorrow and get back underneath so i can take a look at the EGR cooler as its seems to be held in place with a singular bolt on one end and cable ties on the other. so i want to see how f*cked up that is. going to replace it with a second hand one. but it allows me the oppertunity to get under the car again and examine the CV boots, control arm bearings and the like. i will also check those axle bolts too. havent got a torque wrench which makes it a little harder but generally speaking im a good gauge for bolt tightness

i was also thinking it wouldnt be topend/internal issues due to being speed dependant and not RPM. it doesnt exactly get louder, just faster as you increase speeds. though when listening to it it does sound like its coming from the EGR cooler area but nothing rotates up there so god only knows lol

I'm astonished zip ties on the EGR part would withstand the heat back there. Even the plastic component clips above are covered in foil shields.
Yeah, shake the CV axles around. Nothing should move in/out or up and down. And absolutely nothing on the car should be doing the hokey pokey.

 

[secretreeve]

in fairness, before i moved the bolt from the broken lug that wasnt holding anything to another mounting point, im pretty sure the ENTIRE EGR cooler was held on by its pipes. the entire sodding cooler was moveable so i definately need to get under the car so i can see whats going on. im going to replace it either way though. missing bolts, cable ties, broken lugs, no thanks lol.

 

[secretreeve]

Well, CV boot is ripped off the clip at the smaller diameter end. Think that'll be the knocking? Lol

 

[secretreeve]

[url=https://postimg.cc/tsBTXcr5][/URL]

well theres the CV boot. cheap enough to replace im just hoping theres no permanent damage to the joint otherwise looking at a new axle. going to replace the boot first, see how it goes.

 

[secretreeve]

can you get away with jubilee rings instead of CV boot clamps?

in other words, these https://www.jubileeclips.co.uk/assets/uploads/2019/02/HT070-784x1024.png

 

[Rx7145]

I got one of these wasn’t too hard to change. If you buy a complete axle, get one of the GSP brand and not any of the Chinese ones. They’re not balanced correctly.

Audi VW Drive Shaft CV Joint Kit - Febi 109399

Audi VW Drive Shaft CV Joint Kit - Febi 109399

www.fcpeuro.com

 

[secretreeve]

well im going to go with just the cv boot kit, comes with clamps, grease and the rubber boot, about £15. see how it goes. any ideas on the jubilee ring idea?

 

[secretreeve]

so i was swapping out the CV boot, got the drive shaft cleaned up and i noticed this







any ideas? this is obviously the cause of the rotary knocking sound though.

 

[secretreeve]

still getting a bit of a clunk on acceleration and deceleration, not related to the CV boot, could that be the wishbone/control arm ball joints? the one with the 3 bolts from the hub does have some play in it.

 

[kweisel]

I'm unsure how one would place a CV boot kit onto the original CV joint. The axle side diameter would never stretch over the joint? Although from your pictures it would seem much more likely but curious if that spline end fits into the hub and doesn't have a Universal joint on that end. (Have always had FWD CV joint axle replacements) I guess the articulating hub would be that joint.
Was your hub nut tight? The wear on the axle has to come from something else being loose, bottom control arm ball joint?
Any loose/worn components should be changed and from my understanding "play" in anything that isn't rubber is a no go. Gütentite ;-)

 

[secretreeve]

Well had to go out of town yesterday, 100 miles out. On way out the rotary knocking returned. But wasn't present on way back