Knocking sound (with video)

Post Mon Mar 03, 2014 10:38 am

Hi, I can hear a knocking sound coming from the passenger foot well when accelerating briskly on low gears and high rpm. Here's a video. The gear box mount was tightened as found loose to no avail.

[youtube][/youtube]

Cheers,

JF

Post Mon Mar 03, 2014 10:51 am

Does your heater work properly? - Once warm, does it blow hot air all the time?
It sounds like the heater hoses are on the wrong way round and its trying to force water through the heater valve the wrong way.

Hose from the back of the head goes to the bottom stub on the heater.

Post Mon Mar 03, 2014 10:52 am

Mine does the same thing and the heater plays up switching from hot to cold

Post Mon Mar 03, 2014 11:32 am

Thanks guys, the heater matrix was replaced recently but I can't link the issue to that. I know there was a humming present that turned into a knock making me thing something is working its way out.. It could be linked to the heater as the noise seem to come from that area but the heater works as it should , no issues with the hot/cold functions .

Thanks for your inputs guys

JF

Post Mon Mar 03, 2014 11:57 am

JF008 wrote:Thanks guys, the heater matrix was replaced recently but I can't link the issue to that.

Why not? The noise seems to increase with engine speed as the pump pumps the water faster and is trying to push it through the heater valve.

If the matrix has been replaced, the first thing to check is the hoses to the matix are the fitted the right way round.

Post Mon Mar 03, 2014 12:08 pm

It does sound like its inside the car, hose from back of head should go to bottom heater pipe

Post Mon Mar 03, 2014 1:11 pm

jmc330i wrote:
JF008 wrote:Thanks guys, the heater matrix was replaced recently but I can't link the issue to that.
Why not? The noise seems to increase with engine speed as the pump pumps the water faster and is trying to push it through the heater valve.

If the matrix has been replaced, the first thing to check is the hoses to the matix are the fitted the right way round.

Cheers buddy, I meant that I did not notice the noise right after the matrix was replaced so could not link the two with certainty.

I will get it fixed Wednesday hopefully!

Would the matrix have any damage from a hose fuck up? Thinking of it, it was replaced because the previous one (few months old) had split and let the coolant out. The previous matrix might have had the hoses fitted backward too. I had the job done for free under manufacturer warranty by the same mechanic...

I need a second car and start doing more work myself!

Fuck my life

Cheers everyone

JF

Post Mon Mar 03, 2014 1:36 pm

I had exactly the same on a 318 I re lumped many years ago. Swap the two pipes over in the engine bay going to the matrix it worked for me. I only noticed I had them wrong when I looked at another car of the same

Post Mon Mar 03, 2014 1:37 pm

JF008 wrote: I meant that I did not notice the noise right after the matrix was replaced

Takes a while for the valve to become damaged enough to knock.

I need a second car and start doing more work myself!

Ever heard the phrase "If you want a job done properly, do it yourself!"

Post Mon Mar 03, 2014 2:07 pm

Brianmoooore wrote:Takes a while for the valve to become damaged enough to knock.

Will I need a new matrix then? I am not a trained mechanic Brian, just a man with a passion

Its hard to learn for me without the time and space to take everything apart on the mechanical side of things.

Thanks for your help guys

Post Mon Mar 03, 2014 2:39 pm

JF008 wrote: Will I need a new matrix then? I am not a trained mechanic Brian, just a man with a passion Its hard to learn for me without the time and space to take everything apart on the mechanical side of things.

Thanks for your help guys

Don't have to be a trained mechanic to do good quality work on an E30

I started 3 yrs ago having never done anything more than complicated than an oil change and there are plenty more on here who started the same way!

Post Mon Mar 03, 2014 3:17 pm

Motorhole wrote:
JF008 wrote: Will I need a new matrix then? I am not a trained mechanic Brian, just a man with a passion Its hard to learn for me without the time and space to take everything apart on the mechanical side of things.

Thanks for your help guys
Don't have to be a trained mechanic to do good quality work on an E30 I started 3 yrs ago having never done anything more than complicated than an oil change and there are plenty more on here who started the same way!

Don't worry, my neighbours have seen my butt crack plenty.

Post Mon Mar 03, 2014 6:34 pm

It's the electric valve on the left side of the heater box that gets damaged, not the matrix. If the valve hasn't been connected with the flow reversed for too long, it will probably recover.
Follow the water hose from the back of the cylinder head, and see which heater connection on the bulkhead it goes to.

Post Mon Mar 03, 2014 7:17 pm

Brianmoooore wrote:It's the electric valve on the left side of the heater box that gets damaged, not the matrix. If the valve hasn't been connected with the flow reversed for too long, it will probably recover.
Follow the water hose from the back of the cylinder head, and see which heater connection on the bulkhead it goes to.

Cheers Brian, can I call you Brian?

I will investigate tomorrow and hopefully solve the issue like a boss!

Post Tue Mar 04, 2014 1:24 pm

All you guys were right ( well dah obviously ), hoses are fitted the wrong way around. Can I invite you all for a cuppa?

cheers,

JF