S40 V40: Exhaust Manifold removal

[Tom Sawyer]

Hi Guys,

Well - I survived replacing the PCV Oil Trap / Breather Box system - new hoses and all. Now I have a damaged #4 Cylinder Exhaust Manifold Gasket. Probably due to a leaking Camshaft Oil seal, recently replaced with no new oil leaks.

I would be grateful for tips on not screwing up re:
** Breaking studs, seized nuts - what to spray on them to loosen ??
** How to get the exhaust manifold off - been told I may have to pry it off and don't want to damage the ?block?
** Can I just loosen the nuts and pull it back enough to put on the new gaskets - or do I have to remove other parts like the ? turbo drain tubes?

You can tell I am a newbie, but I did the above two jobs so I have a little experience.

Many thanks in advance for your help.

Tom

[canis]

You've probably noticed that access is extremely limited, and it's difficult to see because of the engine's "rolled over" position. A small mirror will help (I use one from a child's hairbrush set, a lovely shade of pink) and an old sofa cushion layed on the slam panel and engine because it might take a while and it's difficult to stoop for that long.

The nuts/studs themselves can be all reached by a variety of extension bars. Attempting to twist them at odd angles will have the socket slipping off, which causes a host of other problems. Ensure sockets are making entire contact by tapping them on with a small hammer to fully seat them onto the nut before attempting to turn them at all.

Torque them all off together. Start at the middle, work outwards, turning them only half a turn at first. Yes, I know it's a pain in the neck, but it's better. As they begin to loosen you may notice some of them are bringing their studs with them. That's okay, but it's important to put them back into the same holes from which they came out. Arrange them on a nearby table or flat surface in a manner as to prevent them becoming muddled. Some people poke studs through cardboard and label them. The nuts are interchangeable, but the studs are not and must not be confused if you can help it.

For a penetrating oil, I use WD40 because it's what I have, but I hear PlusGas is better. I've not tried it myself. In any case, spraying oil madly will also help your tools to slip off. You'll have to use your best judgement on that. Once the nuts are off, they can be lubricated and cleaned up with clean oil, and WD40 is excellent for this purpose. Studs will need a wire brush, nuts can be rattled around in an old tuna tin (I have a dozen or so lying around to keep nuts and other fasteners in logical seperation).

If you have a vice on a bench, then you can begin efforts to remove the nuts from their captive studs, but the short version is, it's not really necessary. A purist would use a variety of techniques locking nuts together to seperate the nuts from their studs and clean them all. Such an engineer will probably remove all the other studs too, to clean those, and the threaded bores which contain them.

You don't have to do all that providing you put the studs (with their nuts) back into the holes they came from, and this is likely what a home mechanic will do. It is important not to over tighten them. If you do, you risk freeing the nuts from their studs on their way back in. This is dangerous, for reasons which will become clear later on.

Once the manifold is off, there is just about space to hold it back against the front bulkhead, although it might be necessary to remove the heat shields. These are a work in and of themselves, and not easy.

When refitting, begin with the nuts which are still attached to their studs. Wind them in until the first resistance is felt. Do the same with the nuts, order is unimportant. Tighten the studs first, use these will draw the manifold to the engine. The reason for this is to prevent the studs encountering extra resistance on thir way into their threaded bores, you want them to find their natural 'comfy' position. The nuts can be tightened afterwards.

This is important. If the nuts held captive on the studs break free on their way in, the stud will be left insecure, but invisibly, especially when using a socket. You can spot this by counting the threads before and after, any studs sticking out too far are studs which aren't fully driven home, causing extra strain on their threads and future problems.

The way to overcome this is to use a "locking" nut. The idea is you drive a second nut behind the first and lock them against each other, then drive the second nut forcing the stud to turn into the hole. Once in, break the nuts apart and remove the locking nut. This can be a two-spanner effort, and can be frustrating, but it's important that the studs are all the way in for them to do their job properly. A thread extra hear'n'there is probably okay, but a visible size difference must be rectified.

Finally, take them all up to the correct torque. You might not be able to get a torque wrnech in there, so you'll need to do this by feel. You can familiarise yourself with the torque effort by practicing on something else, then use your best judgement to feel the tightness of the manifold nuts. In general, they need to be tight enough to not come undone, and to compress the gaskets sufficiently.

Check the tightness again after using the engine for a day.

[pierremcalpine]

Phil_r put out a guide on replacing the PCV oil trap. Instructions on how to remove the manifold are included.

https://www.volvoforums.org.uk/showt...trap+guide+pcv

[Tom Sawyer]

Hey Canis,

I really appreciate your write-up. For some reason I didn't get an email notice of your post. Lots of "hard to do" things for this job. I have decided to go to the dealer to get the job done.

Can you think of anything I could have damaged by having a bad Ex Mani gasket for about 12 months ? Some one on the Internet talked about messing up the related valve.

Many thanks,

Tom

[canis]

Originally Posted by Tom Sawyer

Can you think of anything I could have damaged by having a bad Ex Mani gasket for about 12 months ?

I can't, but I'm happy to be told differently. Anyone else know?

[Tom Sawyer]

Hey Canis -

Brought the car < 2001 S40, 134k on the clock> to the dealer and was ready to pay the $6-700 dollars to have them remove the manifold and replace all the gaskets. The mechanic said they were too many other problems with the car to put more money into a 17 year old car. I had used the mechanic before <his is from Great Britain>, both our wives are school teachers, and we both have daughters in college = not a lot of extra cash floating around. So he declined the job - how is that for integrity !!

He checked the engine compression = 180 for all cylinders; but - he said the crankcase pressure was up and down, but mostly positive. I didn't want to hear that because I replaced the entire PCV system - oil trap and all hoses just last year. Prior to that it was leaking oil from the rear camshaft seal. After I changed out the seal, it was without leaks for a few months, then the front seals started leaking - on the timing belt side. Consequently, the timing belt is not bone dry, but wet with oil, and I am getting a little oil on the garage floor. The rear seal no longer leaks.

I would like to keep the car a couple more years until the mortgage is paid off and the daughter is out of college. I am prepared to sink $2-3k into the car so I can keep it running, this would pay for a timing belt + related stuff, fix the header pipe crack, etc. A few questions, if you would be so kind to jot down your thoughts.

** I took my time replacing the oil trap box and all the related PCV hoses, including the one that is four feet long and wraps around the engine block over to the Turbo. The top hole to the engine block was slightly clogged, but the bottom one was 50%+ clogged. I cleaned out both holes, but later found out I should have dug deeper into each hole for gunk.

howardc64 says there is a Long rectangular drain channel inside the block that may be blocked, pic below


http://www.volvoxc.com/forums/showth...176#post187176

Questions:
** If I remove the oil pan – can I access the bottom hole to the Oil Trap / Breather Box, to further clean it out ?
** Howard was working on a 2001-2007 V70XC – my car is a S-40
--> Should I assume the S-40 also has a “drain channel”, and if so – can I access it after removing the oil pan ? ... to clean it out
** Lastly – I also have a crack in my header pipe / flex joint. One of the Exhaust Manifold gaskets literally fell off the car onto the garage <half of it> due to the rear seal oil leak dripping onto the nut/stud below it. Due to very tight access in the Ex Mani area, it is almost impossible to replace the gasket without taking off the Turbo.
--> Assuming they can weld the crack and I tighten all the Ex Mani nuts – will there be carbon monoxide leaking into the car due to no Ex Mani gasket for the one cylinder ? ... next to the turbo side

Apologies for all the words; many thanks in advance for your time. Regards, Tom

[canis]

Mine is a V40, non turbo, but it has the rectangular breather channel just like you describe. That picture is looking into the crankcase from the bottom up (although it's probably stood on a bench) but the answer to your question is; Yes, you could remove the sump pan and give it a good clean out with something like a test-tube brush, and maybe a bit of methylated spirits to remove the gunk, then clean oil to remove the meths. That's "wood alcohol" in american parlance. Whether you'd need to go through the hassle of cleaning out the PCV hoses, I'm not sure. They won't really need to be immaculately clean, just clear enough to allow gases to escape. Condensed oil evaporate will need to be able to trickle back to the sump. Since you changed the PCV box quite recently, I think it's unlikely it'll be blocked again so soon. But if it is, I rinsed mine with caustic soda rather than buy a new one. Rinse it thoroughly afterwards in plenty of water. Like, a lot of water.

You might be able to get away with just giving them a good blow out.

I'm unable to advise about the procedure is for removing the turbo. I think I would try to dismantle it as little as possible, and try to get it off in one lump. There are many here who do know about the turbo, and I hope they'll shout out. Guys, please advise.

I'm wondering how the gasket fell off the car. Was the manifold partially removed at the time? If the manifold was bolted to the engine, and has been there for donkey's years, it would be crushed so tightly that only an unnecessary exposed piece could come loose. So it might be that the seal is still there, sandwitched between the manifold and the cylinder head. When an exhaust tube is leaking, it can usually be heard hissing and felt with your fingers.

If it is leaking, then some will likely be drawn into the cabin air intake. Might not be much if the fans are at full whack, but on a slower speed, maybe it could be poisonous. But these are just guesses. It would almost certainly be affecting the fuel mixture since the lambda sensor will be getting inaccurate readings. Whether this inaccuracy is enough to worry about is debateable, here in the UK it'd probably show up in the annual MOT test for roadworthiness as our emissions laws have become quite strict in the last couple of decades. As you say, you only need it for a couple more years, if you can bribe/con/plead it through the test it would make sense to just live with it, and maybe open the windows and hit the re-circulate button. :-)

How about this for an idea: While the header pipe is off being welded, loosen the manifold nuts just far enough to wiggle it back a a bit, and examine the leaky one as best you can. If it has been leaking you'd be able to see, maybe? As a last ditch effort, ram a piece of cardboard in it and tighten it up again quickly before anyone notices, heh. I don't know if it's possible, I don't know the arrangement of the turbo, but if you can get a gap enough to slide a cardboard gasket into it... won't be perfect but better than nothing. It's just an idea.

You might find once the header pipe is off it might turn out to be easier than you thought. Sorry, I honestly don't know.

[Tom Sawyer]

Hey Canis -

Many thanks for the time you put into your replies - the forum needs to give you a couple of Gold Stars ! I'll reply to your comments one at a time:

Canis: I'm wondering how the gasket fell off the car. Was the manifold partially removed at the time? If the manifold was bolted to the engine, and has been there for donkey's years, it would be crushed so tightly that only an unnecessary exposed piece could come loose. So it might be that the seal is still there, sandwitched between the manifold and the cylinder head. When an exhaust tube is leaking, it can usually be heard hissing and felt with your fingers.

Tom: I dedicated a whole Saturday to removing the Exhaust Manifold "ExM", cleaning it up, and replacing the gaskets. Had all the gaskets, four each of studs, nuts, and two types of washers - in case I broke/lost anything. Haha - got about 30 minutes into the job and realized there was not enough room between the block and the firewall to pull the ExM off the studs ! I could pry it loose about 3/4", but still needed another 1" to get it off the studs. And then I had to deal with the stuff attached to the ExM. Attached is a pic of the Ex Mani with Red arrows. The Blue Arrows are the ? head; the nuts / studs attaching the ExM to the block, are under the Blue arrow thingy i.e. you can't see them without a mirror. And finally - there is VERY little room to work in.

So - all eight nuts on the ExM came of with no effort, but one stud came off with the nut. I'm thinking this is where the broken ExM gasket came from. It split in half and since there was no stud to hold it up, it just fell off.

[Tom Sawyer]

Game Plan:

Take it to a muffler shop tomorrow, find out if they can weld the crack in the header pipe / flex pipe, and ask if the missing / damaged gasket will put exhaust inside the car.

If they can weld it, tell them I'll be back next week. Then dedicate another Saturday to prying the Exhaust Manifold "ExM" away from the block. Put a wooden stick between the block and the ExM to keep the space open. Next, cut two notches in the gasket < see red arrows in pic > so hopefully I can slide the new gasket over the side of the stud. Tape it in place and work on the next one. I'll try to cut the notches so the gasket hole grips / just barely goes over the stud and "hangs on" the stud.

I have a small camera about the size of a baby's little finger, with a light on it, a six foot cord that plugs into my Laptop. About $20 from Amazon ! I'll use this camera to help me through this process. And - with the good Lord's blessing - attach all four new gaskets. Then put everything back together and off to the Muffler shop !

Challenges: very tight space, about 3/4" to maneuver the new gaskets in place, hope the tape keeps them in place, remove the old gaskets - if necessary - and find out if any part of the old gasket is stuck to the ExM ! Here is the big one: the ? head hangs over the ExM studs, so I may have to do all insert the new gaskets from the bottom of the ExM !

[skyship007]

You should be able to hear a leaking manifold gasket.
Removing them can be a real PITA and I would be tempted to botch the job by tapping in some alloy foil to the section that leaks after using some exhaust sealant in the gap.
I still use WD40 and a small blowlamp for stuck nuts, although there are better products out there that contain stronger acidic solvents and light oils with Moly in them.

Manifold gaskets fail for a variety of reasons, including overheating, oil contamination and corrosion.

If you want to avoid oil trap, CCV or PCV sludge problems, use a high detergent full synthetic Xw30 in a petrol or Xw40 in a diesel, don't do too long an OCI or overfill the oil level.
If the valve fails the entire unit has to be changed and although you can try using an oil flush additive, they are very difficult to clean without using acetone and that can damage the seals.