Vacuum leak fix it?

joycem

Newbie
Joined
Jul 25, 2025
Points
1
My 97 Z3 has 250k miles. It just got new plugs, coils, injectors and boot. Now they say it has an air leak which is $700. So am I now in the spot of vanishing returns or do I keep fixing things. It has been great till now.
 

Jack Ratt

Zorg Expert (I)
Supporter
British Zeds
The West Country
Joined
Dec 3, 2013
Points
200
Location
TRURO, CORNWALL
Model of Z
2.8i AUTO and 2.8i MANUAL
Check all the intake rubber / plastic pipes for splits. Check the rubbers around the injectors. Easy DIY job to change these and a very common problem on high mileage cars
 

Shelly

Zorg Expert (I)
Supporter
British Zeds
East Anglian Crew
Joined
Jul 9, 2013
Points
201
Location
Norfolk
Model of Z
Z4 2.0 20i M Sport sDrive

ktnez99

Zorg Guru (IV)
British Zeds
Joined
May 18, 2018
Points
164
Location
West Midlands
Model of Z
Z3 2.8L
Is this when a “smoke test” comes into its own? Someone with far more knowledge than me may pop along soon to say one way or the other. And hi! Welcome to here @joycem
 

Smudgemanuk

Zorg Legend
British Zeds
Joined
Dec 1, 2024
Points
73
Location
Bicester, Oxford
Model of Z
2.8l TU pre-facelift z3
Welcome to the forum!

From when I removed the intake manifold off my 2.8tu, I know how bad the vacuum hoses can be

Intake pipes
My post MAF intake pipe has a HUGE hole right in the crease where it concertinas, so that was definitely not helping my engine.

Vacuum pipes
I think this is 2.8 only but.... There are two bits coming off the vacuum unit, which is accessible without taking the intake off, both of those were awful, more holes than pipe. One goes up to the fusebox (as it travels with the with the main loom to the exhaust valve in the backbox) and the other goes up to behind the intake manifold and meets at a joiner in line with where the intake meets the head. Then from there it travels by hard vacuum line around the engine to near the secondary air pump and switches to rubber line (mine was also very perished) before going into the thing with the silver cap (not quite sure what it does but it is near the front offside of the engine). There are also 1-2 vacuum lines relating to the CCV which I changed as they were crap.

I have heard the smoke test works well

It would be helpful for you to add what engine is in your z and location to your profile so people can give specific advice, and saving you retyping it each time. This can be done my clicking on your username near the top right corner and going to account details.

This is a link to a thread to help with parts buying:

Hope this all helps a bit!

Chris.
 

Mint

Zorg Expert (I)
Supporter
British Zeds
East Anglian Crew
Joined
Sep 23, 2012
Points
222
Location
Stafford
Model of Z
2.2 Sport Individual
Hi and :welcome: to the forum from me too in Stafford. Yes a smoke test will find any leaks in the system.
 

Delk

Zorg Guru (III)
British Zeds
Joined
Oct 9, 2018
Points
125
Location
Hemsby Norfolk
Model of Z
Z3 3.0T
I see smoke testers on the sales sites but how many people have access to one? Just wondering if it's something I am missing in my collection.
 

AntStark

Zorg Guru (III)
Supporter
British Zeds
Joined
May 15, 2021
Points
143
Location
Hampshire
Model of Z
2002 3.0 Sport
I see smoke testers on the sales sites but how many people have access to one? Just wondering if it's something I am missing in my collection.
I made my own ..works a treat
IMG_1544.jpeg
IMG_1548.jpeg
 

AntStark

Zorg Guru (III)
Supporter
British Zeds
Joined
May 15, 2021
Points
143
Location
Hampshire
Model of Z
2002 3.0 Sport
How about doing a write-up for us inexperienced members on “How to make your own smoke tester”? @AntStark
You need a big jar with a lid, a cheap soldering iron, baby oil soaked cloth and a cycle pump. I’ll take some more pics if you are genuinely interested.
 

ExMX5owner

Moderator
Staff member
Global Moderator
Supporter
Australian Zeds
Joined
Aug 31, 2022
Points
126
Location
Queensland, Australia
Model of Z
99 2.0
You need a big jar with a lid, a cheap soldering iron, baby oil soaked cloth and a cycle pump. I’ll take some more pics if you are genuinely interested.
That explanation did it for me, Cheers. :thumbsup:
 

ktnez99

Zorg Guru (IV)
British Zeds
Joined
May 18, 2018
Points
164
Location
West Midlands
Model of Z
Z3 2.8L
You need a big jar with a lid, a cheap soldering iron, baby oil soaked cloth and a cycle pump. I’ll take some more pics if you are genuinely interested.
I am! Please.
 
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