Question - Removing Intake Manifold

[Tidybuoy]

I've replaced all of my vacuum lines except the ones to the idle control valve and oil seperator - which I will need to remove the intake manifold for this.

I'll be doing this project in the next couple of weeks and I thought I'd ask for any advice I can get.

I've read up on Clarks Garage but I'm wondering if anyone has any tips:

Do I need to use gasket sealer with the port gaskets?
Any other seals under there that I don't know about - I've already got all the hoses and the seals for the oil seperatro.
Is this the time that I should also be replacing my oil cooler seals?
Anything else that I may need to do well the manifold is off?

Since this will be a once in a great while type of project, I thought I would ask so I can order any parts that I may need.

Thanks in advance.................Vern

[Techno Duck]

No gasket sealer on manifold gaskets, install them dry. You can put a dab of grease to hold them in place though. Good time to replace the heater control valve also.

[87944turbo]

Do I need to use gasket sealer with the port gaskets?

No, but its not a bad idea. I do.

Any other seals under there that I don't know about - I've already got all the hoses and the seals for the oil seperatro.

There is a seal under the top of the AOS cover that is between the cover and the body of the AOS. I wouldn't worry about it though.

Is this the time that I should also be replacing my oil cooler seals?

Never a bad idea, but not related to the intake manifold. However, it is an excellent idea if the headers are ever off the car.

Anything else that I may need to do well the manifold is off?

Will be a little easier to check/clean your DME grounds (Procedure from Tom's site)

Might also want to replace your fuel injector seals if this hasn't been done recently.

[Tidybuoy]

Hey Thanks! All good tips and I will definately take a look at the ground wires. I replaced the injectors seals about 6 months ago but I may use this time to replace the heater valve and any hoses down there.

Thanks again..................Vern

[onZedge]

Excellent suggestions so far. You don't have to have the intake off for these, but if you are eliminating all possible vacuum leak sources, I would replace the o-ring where the dipstick tube plugs into the block and the oil filler cap o-ring as well. Don't forget the brake booster hose.

While you have the intake off, check the big vacuum nipple on the bottom to make sure it is tight (it's a press fit). Someone here recently had a running problem that had some of us scratching our heads. The problem turned out that the big vacuum nipple pulled out of the intake manifold. Now that's a big vacuum leak.

[Tidybuoy]

Thanks again.

So far I have replaced:

All rubber vaccum hoses (except funky hose to oil breather & back of idle control valve)
All cloth covered rubber vaccum hoses going to charcoal cannister
Main Intake boot
Hard Plastic vacuum lines & rubber ends
Brake booster hose and check valve
Fuel injector seals

Next on my list:
Funky hose going to the oil seperator
Hoses going to the idle control valve
seals on oil seperator
bottom of dipstick tube (it's leaking a tiny bit)
Seal on oil cap

The car runs fine but it did have a hunting idle which is 99% cured but still hunts a little when the car is cold. I've only got 27k miles but the car is still 19 years old and in my past cars, correcting vaccum leaks seamed to improve engine running more than anything else - especially in my 914 and old bmw 320i - plus I feel better knowing nothing is going to break and leave me stranded.

I didn't know anything about the vacuum nipple on the bottom of the intake but I'm glad to hear in advance what to look for.

Thanks again..................Vern

[onZedge]

Originally Posted by Tidybuoy

...I didn't know anything about the vacuum nipple on the bottom of the intake but I'm glad to hear in advance what to look for...

Actually, there are two. Bigger one for the idle control valve, and the other is for the brake booster/EVAP canister purge valve.

[John_AZ]

Rubber mounts for idle control valve-928-110-191-10-m100-----$4.25 x 2 (Pelican).
While you are close by-check the heater control valve pivot for leak-crusty white deposit and replace if necessary ($20 and small hose to block $8). There was a Porsche recall for the short fuel hose to the fuel rail years ago. The dealer replaced free and hand washed my car before pickup. http://nhthqnwws112.odi.nhtsa.dot.gov/acms/docservlet/Artemis/Public/Recalls/1990/V/RC-90V061-NN.PDF
John_AZ
1988 924S
1987 924S

[speedracing944]

Originally Posted by onZedge

Excellent suggestions so far. You don't have to have the intake off for these, but if you are eliminating all possible vacuum leak sources, I would replace the o-ring where the dipstick tube plugs into the block and the oil filler cap o-ring as well. Don't forget the brake booster hose.

While you have the intake off, check the big vacuum nipple on the bottom to make sure it is tight (it's a press fit). Someone here recently had a running problem that had some of us scratching our heads. The problem turned out that the big vacuum nipple pulled out of the intake manifold. Now that's a big vacuum leak.

That someone was me The nipples appeared to be epoxied in and the epoxy degrated. I have heard of a couple of others having the same trouble.

What I did to fix mine (and I would suggest others to do the same) is to cross drill a hole into the manifold and the nipple cross ways and use a tap to cut threads into the manifold. I then ran a bolt through the manifold and through the nipple. It shoudl never come out again.

BTW my car was down 1.5 months trying to solve this problem because of school and everything else going on.

Regards,
Speedy

[EMBPilot]

Intake, Vacuum, Idle Control, Fuel ect project