Interesting turbo noise - ZD30

[Solanum1]

Hey guys!

Last week and a bit I've noticed an added noise above the usual turbo whistle when going up gears. It wasn't an overally huge noise but enough for a bit of an inspection.

After a well earned de-grease and wash I noticed a very small leak in one of the hoses - have replaced both hoses with a silicone type and have clamped both down well enough to have a decent seal (or so I believe anyway).
At the same time I did this, I also did my regular 5K service.

Took the ute for a bit of a spin afterwards and the noise had increased, but only for say 5min and then no noise what-so ever - back to normal. Maybe due to it coming up to proper running temp, or maybe hoses sealing off a bit better? But then went on the highway for a run and 5th gear between 80 & 90km was a lot louder then usual. It was a little windy where I was, but I do believe the noise was turbo related.

Any thoughts or idea's?

 

[Rumpig]

Exhaust manifold leak? Seals up once the manifold heats up and expands.
Could be the EGR plumbing as well.

 

[Old.Tony]

I'd look at the EGR as well. Your sig doesn't mention an intercooler - if you have one, check the crimping for any splits. You should see a small oil trail out of the hole unless you have a very efficient catch can installed.

 

[Solanum1]

Thanks guys,

Yeah not intercooled - may look at getting this in the future.

All seals/gaskets look very good for the age of the car (2002) - they look really good actually. Will check out the EGR plumbing like said.

 

[Solanum1]

Checked all EGR plumbing - again, all fine. I'll take the thing for another spin today and see how she go's.

Also noticed while doing the service yesterday that the engine oil level was a tad lower due to a 1000km trip I did the other week. It wasn't all the way down, but was getting close. When I re-filled the 6.7L with new Penrite yesterday I checked the level again this morning and had to add an extra 200ml or so to bump it up to the right level.

This EGR block/blanking plate I keep reading about... could I get away with installing one without an intercooler? My DX is as standard as it gets under the bonnet. Also what is the major benefits of it?

Cheers!

 

[Rumpig]

Yeah you can block the EGR without any other mods.
The pollution system feeds exhaust gases back into the inlet manifold to reduce emmisions under certain conditions. Obviously putting soot back thru the engine isn't going to do it any good in the long term as it builds up in the intake and head and containimates the oil. Theres a sticky thread in the forum about doing it.

 

[Dave]

Sounds like the belt tensioner.

 

[Lawry]

adding on what dave said, is the noise linear with boost eg- occurs when boost rises and falls or is it linear with RPM

 

[Solanum1]

At the current point in time, the noise is only occurring with a rise in boost and only in 5th gear between 80 & 100km. That's around 2.4/2.5RPM. When the noise was occurring with boost between gears (in the first instance) again there was no noise with boost fall.

Well that's good news about no other mod's needed for the EGR block off. Easy as.

Thanks fella's!

 

[mooxie]

Bit of luck, this sounds very similar to a problem I just experienced! I was on a trip and all of a sudden got a new whistle, only above 2,000 RPM when accelerating or under load. I found a small hole in one of the turbo intake hoses and replaced them both with silicone hoses and installed T Clamps. Noise seems to stay the same. After a couple days at the mechanic with no result, I finally found the problem. The new 60mm top turbo hose was slightly too long. This was causing the other hose to skew and not seal correctly. I'd taken the hoses off several time with no change. Cut 1cm off the top hose and it's good as new! Initial sound was caused by the hole in the original hoses, an almost identical sound was caused by the new hoses not being seated properly!

 

[Solanum1]

When I put the new silicone hoses in the other day, absolutely - they have to be pretty much right on size or yes they do push over those small ribs. My top hose is still over a tiny bit, but has been clamped down and is A-OK. Not cheap those silicone hoses...

 

[mooxie]

I made sure mine didn't push over the ribs, but that in turn, pushed the intake pipe towards the passenger side and the 44mm hose to skewed. It looked like it sealed fine, but apparently not!