Inlet Manifold problem

Rowley Birkin QC

My car seemed to be running extremely rough this evening when I pulled out the gate so I immediately turned back around in home.

Checked fuel filter: fine
Checked the fuel depressurisation valve: fuel in the system

So I removed the plastic engine cover to check the plugs, I had problems with them lately. As soon as the plastic cover was off the engine ran a lot rougher which seemed very odd. Then I heard a vacuum so thought a vacuum hose was loose, no luck there either, stranger and stranger.

Turns out that the retaining bolt for the plastic cover has pierced down through what I presume is still the inlet manifold and is drawing air in at that point.



With the bolt re-inserted as shown in the picture the knocking isn't as bad but it is still present as there isn't a perfect seal and air is still being drawn in.

Anyone care to offer advice as how to proceed? Can the inlet manifold be replaced easily or would something as crude as silicon applied around the bolt create the seal again?

It's a 1.6 16v Opel Vectra and I'm getting very very sick of it:mad:

Cheers for any replies, can't afford a mechanic at the moment, back to college in 2 weeks.

Darragh29

bigkev49 wrote: »

My car seemed to be running extremely rough this evening when I pulled out the gate so I immediately turned back around in home.

Checked fuel filter: fine
Checked the fuel depressurisation valve: fuel in the system

So I removed the plastic engine cover to check the plugs, I had problems with them lately. As soon as the plastic cover was off the engine ran a lot rougher which seemed very odd. Then I heard a vacuum so thought a vacuum hose was loose, no luck there either, stranger and stranger.

Turns out that the retaining bolt for the plastic cover has pierced down through what I presume is still the inlet manifold and is drawing air in at that point.



With the bolt re-inserted as shown in the picture the knocking isn't as bad but it is still present as there isn't a perfect seal and air is still being drawn in.

Anyone care to offer advice as how to proceed? Can the inlet manifold be replaced easily or would something as crude as silicon applied around the bolt create the seal again?

It's a 1.6 16v Opel Vectra and I'm getting very very sick of it:mad:

Cheers for any replies, can't afford a mechanic at the moment, back to college in 2 weeks.

Am I reading that pic completely wrong or is that bolt for holding down the rocker/cam shaft cover???

Rowley Birkin QC

Yup thats what its for, hence the confusion!

God-damn Opel! Any ideas Darragh?

Rowley Birkin QC

This is it with the cover back on, the bolt highlighted is the top right.

DublinDilbert

i could be reading this wrong, but based on what you've said above when you take out the bolt, you can hear air being sucked in??

I presume there's a crank case ventilation valve on these for emissions reasons... It sounds like the PCV is gone and its constantly sucking air in from the crank case and not just on the engine run down like it should.

If you open up the oil filler cap, you'll probably get the same effect as removing that bolt.

If the above is true, your letting un-metered air into the engine, hence it ends up running lean.

Rowley Birkin QC

Yeah the knocking definitely sounded like it was running lean.

Whats the fix?! Rough and dirty or is it a big enough job?

Cheers for replying, not the most exciting topic in motors I know.

DublinDilbert

You'll need to find the PCV valve and replace it, if that is the problem... they are normally very cheap, in or around €30...

Not sure if the old one could be cleaned, but i think in most of them there's a diaphragm that gives in.

http://en.wikipedia.org/wiki/PCV_valve

Lucifer

Your problem is not the pcv valve. that bolt in the pic is not on the rocker cover. that is the manifold as you said. it is just for holding on the engine cover. the rocker cover can be seen in the bottom left of the picture. If you think it is drawing in air, try spraying it with something like wd40 or carb cleaner. if it is drawing air, when you spray where the leak is you should notice the engine sound change. if you do find the leak there, the correct way to fix it would be to replace the manifold but if you are tight for cash at the moment you should be able to fix it up with some sealer to get you by.

DublinDilbert

Lucifer wrote: »

try spraying it with something like wd40 or carb cleaner.

Would WD40 not have silicone in it, hence possibly kill your oxygen sensor? I'm not sure how much silicone it takes to kill one, but just in case... carb cleaner should be fine....

Rowley Birkin QC

Lucifer wrote: »

Your problem is not the pcv valve. that bolt in the pic is not on the rocker cover. that is the manifold as you said. it is just for holding on the engine cover. the rocker cover can be seen in the bottom left of the picture. If you think it is drawing in air, try spraying it with something like wd40 or carb cleaner. if it is drawing air, when you spray where the leak is you should notice the engine sound change. if you do find the leak there, the correct way to fix it would be to replace the manifold but if you are tight for cash at the moment you should be able to fix it up with some sealer to get you by.

Any particular sealant? I was thinking that if I was going to go down that route for the moment until I can replace the manifold that the orange stuff (can't think of the name of it) would be best. Instant Gasket is it? Or would ordinary silicone or gripfill do the job?

As to carb cleaner, when you say spray it do you mean into where the vacuum is? Would a bottle of Redex through the fuel tank have the same effect when the vacuum is plugged?


Once again cheers for the help, it's greatly appreciated.

DublinDilbert

bigkev49 wrote: »

Any particular sealant? I was thinking that if I was going to go down that route for the moment until I can replace the manifold that the orange stuff (can't think of the name of it) would be best. Instant Gasket is it? Or would ordinary silicone or gripfill do the job?

As to carb cleaner, when you say spray it do you mean into where the vacuum is? Would a bottle of Redex through the fuel tank have the same effect when the vacuum is plugged?


Once again cheers for the help, it's greatly appreciated.

Your using the carb-cleaner to try locate the vacuum leak, when you spray it on the vacuum leak it will get sucked into the air intake and you'll hear the engine speed up....

Dirty_Diesel

I would have thought that it could be a pcv problem, but if it's a 1.6 ecotec vetra I would also check the egr valve. It is a common problem with this engine. I know of one that went through 3 in 2 years! This would also give a rough idle and poor accelration.

Rowley Birkin QC

I thought of the EGR as I have had to replace two before on this car but the vacuum leak seems to be strong and coming from the point shown above. Going to try some sealant on it this morning and a bottle of Redex through the fuel system.

Cheers again.

Dirty_Diesel

A small vacum leak is not going to give rough/poor running. A vacum leak can only be on the inlet manifold, raising the revs slightly. A large vacum leak would affect the running as the afm is not measuring the incoming air through the leak.

Rowley Birkin QC

Dirty_Diesel wrote: »

A small vacum leak is not going to give rough/poor running. A vacum leak can only be on the inlet manifold, raising the revs slightly. A large vacum leak would affect the running as the afm is not measuring the incoming air through the leak.

It was a large enough leak tbh, I put some high temperature exhaust putty sealant on it and let it set and it definitely helped. Also dumped about 3/4 of bottle of Redex into about half a tank of fuel and let the engine run for a while.

It ran rough for about 90 seconds and then settled back to a normal enough idle. However the knocking, while greatly reduced, is still there.

Could the temporary loss of vacuum and running with unregulated air intake cause permanant damage? I only need this car for another 12 months and it has little or no resale value so big expenditure on it is not a preferrable option.