Couple questions from a new S70 Owner...PCV/Head Gasket?

creepingdeath94 · Post by **creepingdeath94** » 13 Jun 2010, 08:30

Alright, I am new to this forum and searched around a little but still have a couple questions as this car is new to me and it is pretty unique from what I normally work on. I picked up a 1999 S70 NA with a blown head gasket...water and oil mixed, had been overheated, etc. I finally got around to doing the job and removed the head, had it decked, got new gaskets, head bolts, water pump, timing belt, etc. Well, long story short, I got everything back together and don't feel I did anything wrong, but it seemed to have the same issue as when I started. Looked like water in the oil (but it seemed like less), pressure spewing out of the dipstick tube, didn't want to idle if revved up. Does this sound like a PCV system issue still or would it run fine if that was all it was? Before I started the job, it spewed oil all over the place on the short drive into the shop from behind the building...now it doesn't do that anymore, but it still has pressure in the dipstick tube and if you try and drive it, it doesn't like to idle down when revved up. It will stall out. Seems like I have head issues still, but wanted to ask as I came across this PCV thread and I know so little about Volvos.

I also have a little rubber hose that comes off my intake hose to the manifold that has a little metal 45* fitting/tube on the end of it that as of now floats in the breeze. It goes somewhere and obviously has a home as now it would be picking up un-metered air into the motor as it is after the MAF. It was disconnected when I started so I have no reference as to where it should go and I looked around the area pretty good...but again, not so familiar with Volvo.

Basically, sorry for the novel here, but I am wondering if I need to yank my head back off and search for cracks and have it totally gone through again to see what I missed, maybe I scratched the head gasket or something sill upon re-install (but this isn't my first head gasket and I am pretty careful when I work on things I don't do regularly), or is it possibly this PCV system issue? It is non-turbo and I am sure it has never been done based on the looks of the car and maintenance (or lack there of) I noticed when I got it. Any help would be tremendously appreciated. I really need this car repaired and running properly. Thanks.

Post by **1997volvo850** » 13 Jun 2010, 09:14

It sounds like you have problems much more serious than the PCV system. Eliminating the oil/coolant problem
seems related to head gasket issues.

I am familiar with the PCV system. I believe this is one of the most misdiagnosed repairs on older
Volvos. Folks see smoke coming out the dipstick and they automatically recommend a PCV
replacement (Dealer ~$700). A few of us argue that the extra blow by in older engines overwhelms
the PCV system that was designed for handling the blow by in new engines.

Case in point. I recently took my Volvo in for a Check Engine code P0171 (running lean). Volvo dealer
said they'd start with the PCV system ($700). I passed. I fixed the "lean" problem by replacing a $17
fuel filter. I had cleaned my PCT valve and checked for good vacuum in the system so I knew this
was not the problem.

PCV replacement was also initial diagnosis on second 850. I also checked PCV and PCT valve and both
are ok. At this point I'm confident that the PCV system is fine in both of my cars.

I believe the BIG thing with the PCV system is to make sure the PCT valve(Turbo) or Flame trap is clean.
You can clean both in place if you want. There is a thread on it here.

I have a Turbo with PCT valve. I applied a vacuum to the larger hose (at air intake hose) and if I feel a vacuum
from the oil dipstick and the hole on top of the engine so I know my hoses are not completely blocked. Even with a
clear system I get smoke out the dipstick. That's what 230K miles does.

In your case I believe you have a fire trap instead of PCT valve. Making sure it is clean is important.

As long as the hoses and flame trap/PCT valve are not blocked any increase in pressure will result in blow by gasses
being forced out the Flame trap/PCV and into the intake.

Even so gases will still escape from the oil dipstick. Many people at this site have reported seeing smoke
from the dipstick, replacing the PCV system, only to see smoke still coming from dipstick.

Others have ALSO correctly pointed out that if I replace my valve seals and redo my rings I would have
less blow by gases to worry about. It is my understanding this would also cost upwards of $1500 to have done.

There does comes a point when the hoses start to disintegrate at which point a complete PCV replacement
is a good idea. Though you could get away with replacing hoses since most have reported the oil separator
is rarely clogged. The complete PCV kit is $115.

If you have the intake manifold off you might want to inspect (look for a diagram on this site) the various
hoses for the PCV system. If there is oil leaking all around them you need to check connections or replace
hoses. I've seen photos of hoses that had completely disintegrated with oil every where.

The PCV probably takes a lower priority to the head gasket problem but you can surely check things out
while you're in the area.

Good luck.

Post by **Ozark Lee** » 13 Jun 2010, 09:21

Do a compression check, this sounds very much like a stuck ring building up crankcase pressure with the blow-by.

..Lee

creepingdeath94 · Post by **creepingdeath94** » 13 Jun 2010, 09:31

I was going to try a compression check next. I also only decked the head...I didn't do a valve job/guides/etc. as it seemed pretty good but I may just have to break down and do a complete head rebuild. I was trying to whip it out quick and cheap, but as usual when I take short cuts I get burned and have to do things twice. It looked to be a relatively good shape head though as far as valves and such, but you never know without properly checking it and going through it properly.

Anyway, I will be in there tomorrow for sure...maybe this afternoon, we'll see. I will do a compression check as well as some other things. Any idea what the little hose/fitting to the air intake boot is supposed to go to? I will get a picture when I get in there next if possible. I will also try and figure out my cameras video function and record the dipstick tube spewing and you guys see if it is the same condition as what is explained in the PCV issue or something else. Thanks for the help everyone.

creepingdeath94 · Post by **creepingdeath94** » 13 Jun 2010, 09:32

Ozark Lee wrote:Do a compression check, this sounds very much like a stuck ring building up crankcase pressure with the blow-by.

..Lee

If this is the case, what can be done? I would have to pull down the motor then wouldn't I? Or would you happen to have a trick that sometimes frees up the ring?

Post by **jblackburn** » 13 Jun 2010, 09:36

The dipstick shouldn't spew ANYTHING unless the engine is warmed up first.

That hose attaches to the left side of the intake manifold on my '98 behind the alternator. I do not know whether or not the '99 base model is different there as the XC's and R's are.

creepingdeath94 · Post by **creepingdeath94** » 13 Jun 2010, 09:43

jablackburn wrote:The dipstick shouldn't spew ANYTHING unless the engine is warmed up first.

That hose attaches to the left side of the intake manifold on my '98 behind the alternator. I do not know whether or not the '99 base model is different there as the XC's and R's are.

It was warmed up after I did the head gasket job this time. Also, it is not really spewing anything now...maybe a bit of residue that eventually collects and runs down the tube a bit after running a while, but definitely not spewing oil the way it did when I first brought it in. When I ran it from behind the building to inside my shop though, it couldn't have been running more than 5 minutes or so. I was pretty sure it had a blown head gasket then though as the car was grossly overheated by the owner I bought it from. After I replaced it/decked the head though, it should have fixed that unless we all missed a crack in the head or something. Anyway, I don't think it really gets pressure or any of the white smoke/vapor now until it has been running a bit...warmed up some. It seems to start fine cold too, but when it warms up, it will not want to start without throttle and if put in gear/driven/revved up and let off, it will stall. But you can feather the throttle and keep it going until it settles down and it stays running fine then. Had the A/C on as well for some of that, just for kicks to see if it made a difference with the idle. Seems to run ok above 1000 rpms though...just doesn't like idle. That's why I was wondering about that one hose or some other vacuum leak. I really am just grasping at straws trying to avoid pulling the head again if I don't have to, but I have no issue pulling it again to fix this if I know what I missed or what is going on to be fixed.

Post by **jblackburn** » 13 Jun 2010, 09:49

If it is that hose, it is responsible for pulling a vacuum for the PCV system, and may cause some smoke to be thrown up the tube. But, it should make NO difference in the idle or running, aside from throwing an O2 sensor code for unmetered air in the system. I would start with a compression test as Lee said, and see if you can get some clue as to what's going on without ripping it apart again.

My guess would be that there is a slight warp somewhere that causes the head gasket to let loose again after the engine gets warm.

creepingdeath94 · Post by **creepingdeath94** » 13 Jun 2010, 09:56

jablackburn wrote:If it is that hose, it is responsible for pulling a vacuum for the PCV system, and may cause some smoke to be thrown up the tube. But, it should make NO difference in the idle or running, aside from throwing an O2 sensor code for unmetered air in the system. I would start with a compression test as Lee said, and see if you can get some clue as to what's going on without ripping it apart again.

My guess would be that there is a slight warp somewhere that causes the head gasket to let loose again after the engine gets warm.

Where should it go on the metal fitting/tube end? Down to the flame box? I don't know where it is supposed to go from the intake tube. I plugged it for now to see if it helped with the running issue, but it did not...so I will be pulling the plug off next time I mess with it and continue trying to find out where it goes.

I will also do a compression check then when I am in there next as well. What numbers am I looking for? Not a leak down correct, but a compression check? Looking for pressure numbers from combustion? Also, is there any special technique or number of revolutions or anything for the compression check I should know about? Thanks again guys, this really is a tremendous help for someone new to the Volvo world.

Post by **jblackburn** » 13 Jun 2010, 10:01

I believe that's where it does go.

I would start with just a compression check for now, if you've got the tools for it. You should see 180-200 psi on a used 2.4 engine. Try it when cold, try it with some oil in each cylinder to rule out rings, and maybe try it again when warm to see if my theory stands up. Once you do it the first time, it's very quick to go about it again. You'll want to pull all of the plugs out, then crank the engine over 5-6 times with the throttle wide open, and take the best number you get for each cylinder.

It's almost certain something's letting oil into the coolant if you've got it floating around again, so leak down might not be very useful.