Odd Exhaust Valve Issue 1999 V70

Post by **nickelghandi** » 17 Jul 2018, 15:06

Hey guys,

You probably remember me posting a very lengthy post a while back regarding my 98 S70 GLT. I have that sorted now and posted in that thread. I am now tackling the issue of my V70 and would like a bit of advice.

I bought the car for a song with a dead miss on cylinder 1. I figured, valve, head, head gasket, etc. Driving it around though, it sometimes acts like there is nothing wrong. There is also no mixing of fluids and the only loss of coolant seems to be due to the leaking heater core. This leads me to believe that there is something else going on, and before I tear into it, I want to do my homework.

I have a boroscope camera that I can send into small places for troubleshooting. The resolution is awful, but I can usually tell what is going on. It's real drawback is that there is no normal way to look in the reverse direction. I have managed to get around this by taping the camera head onto the feed wire. I did this and examined the valves. See the photos below.

From the photos you can see that one valve is clearly open. It is the right exhaust valve when looking at the engine from the front. It stays open no matter to which point the engine is cranked. Like I said, the camera quality is pretty bad, but on the live feed, it looks a bit better. None of the valves appear damaged and the piston surface and sidewalls look great.

It is pretty oily in there, but that is because I tried dropping some oil in to check for compression loss due to worn rings. That was not the case. Still, the spark plug was fairly oily so there is definitely a leak. Pressurizing the cylinder results in air escaping through the exhaust. So my questions for those with more keen eyes are as follows:

Does this valve look bent or just stuck?

Is it easy enough to take off the valve cover? I cannot find a write up or video anywhere of that being done. I can turn a wrench pretty well, but I am much more cautious with my Volvos than say my F-150.

Thank you for any suggestions.

Post by **SuperHerman** » 17 Jul 2018, 16:53

On taking off the valve cover - plenty of write ups - search head gasket and then look here:

viewtopic.php?f=9&t=85853

You will need to fashion the special tools to do this job or order/borrow them. You are basically doing a timing belt change and cam seal replacement the hard way - so factor in replacing items as required.

Regarding the valve - does it move at all or is it stuck? If it moves that would suggest it is bent, there is an obstruction not allowing it to fully close, the tappet is damaged or the cam itself is damaged. As it stays in place the valve spring seems to be at least partially functioning. What kind of noise is the cylinder making. Place a screwdriver or pipe on it and listen. If you understand how valves work - listening will give you good information.

Can you see any marks on the pistons suggesting piston to valve contact?

If it does not move it should be making a fair amount of noise, or it did in the past, before something was damaged.

On another line of thought you state the problem is intermittent. Is this an exhaust or intake valve? It is possible the valve is pretty gummed up and it gets stuck - you should hear a change in engine chatter when this happens (besides the obvious misfire).

In your first photo at about 10-11 o'clock I see two lines that I do not know what they are. Could this be a valve retainer? A Volvo valve looks just like any other valve - what I see in that area in the first picture is abnormal.

If a retainer cam out you may have a broken spring, damaged tappet ...

Can you pull another plug and scope to see if maybe a valve seat has fallen? Hard to tell but a comparison would help.

To diagnosis pulling the intake, if it is an intake valve, or the exhaust manifold, if an exhaust valve, would be required. Pulling the cam cover is required no matter what you do.

I suppose I would attack the issue as a head gasket change, but start by pulling the valve cover and cams. Maybe you get lucky. After that I would prep it for a head gasket change.

Dmck · Post by **Dmck** » 17 Jul 2018, 16:59

It looks like the one side of the valve is more off the edge than the other but it's hard to tell really.

Since you have access to the camera I would take off front passenger tire and crank the engine until you have that specific cylinders other exhaust valve open so you could compare them. (Or just find the cylinder that they are open in to compare it.)

Taking the valve cover off will only get you to fix a problem dealing with a possible jammed lifter or possible broken/dead spring or the boot base broke and the boot is off the valve. So if you are lucky it could be that.

That's why I would want to crank the engine to compare and see if the valve currently is completely open. If the other valve looks totally similar when engage then maybe you lucked out and it's not bent/seized

No matter what you will need to open it up. This video will have all you need. Robert also has a rebuild head video where he breaks down dealing with the valve assembly itself

Dmck · Post by **Dmck** » 17 Jul 2018, 17:13

Also maybe the green is just the bad lighting or resolution but it sure does look like coolant color wise to naked eye

Post by **nickelghandi** » 17 Jul 2018, 18:45

SuperHerman:

It does not make any noise and it always seems to be open regardless of what position the engine is cranked to. My next step was going to be to remove all spark plugs and manually rotate the cams to see in real-time if there is any movement. Rotate a bit, check, rotate a bit, check, etc. It is an exhaust valve. I agree, the first picture indicates an abnormal condition.

Engine idles rough and slow off the line, but then (in very short intervals) it will be fine. I do not drive it much because of the issue and have only driven for troubleshooting.

Dmck:

It does appear to be off axis a bit, but that could be my crappy camera. I think I will have to just pull the head and see what I am dealing with. Obviously that starts with the valve cover, and things on top attached. I have watched all of Robert's cylinder head videos at length and have a pretty good general idea. I just don't want to get deep into this with parts and time and find out it needs a new engine or something extreme, or break something along the way.

The green is most certainly due to the lighting. Changing camera angles changes the color of different aspects from green to red to blue. The camera is just bad at processing light I think. I should have included a basic photo from the camera to illustrate how different light sources can affect it. I dyed the coolant and there is no entry into the combustion chamber. The only place I can find it is near the heater core inside. That job comes after this one though lol.

All:
It looks like I will have to open it up and just see how it goes piece by piece. Should be a good learning experience for me.

Robert: If you see this thread, let me know the next time you will be in KY! I could use some help with this and can drive to NKY/Cincinnati as it is only about 2 hours from Frankfort even with a dead cylinder. Anyone else nearby that would be willing to lend a hand for some quick cash and cold beer? lol.

Post by **SuperHerman** » 17 Jul 2018, 20:37

: Strange.jpg (370.37 KiB) Viewed 1874 times

What are these two things?

Post by **erikv11** » 17 Jul 2018, 21:09

I'm thinking likely a broken valve spring.

Dmck · Post by **Dmck** » 18 Jul 2018, 06:43

im confused by that too Herman... how could it Be a valve spring though? that would mean the valve spring is on the wrong side of the valve seat/"holder"

I'm thinking it's possibly something that fell into the valve area from the exhaust manifold or intake manifold hole (not sure which side that's on) I can't tell if that's the same valve in all the photos.

If that is the same valve from different angles it may be the right thing to just remove the manifold first and pull out whatever that is.

It looks like proper deminsions to be half of the valve boot that holds the spring down and connected to valve.. but still doesn't make sense on that side of the head..

Post by **Clemens** » 18 Jul 2018, 06:53

+1 on taking the exhaust manifold off and check what that is. maybe the PO´s wedding ring long gone missing ...
The only thing that could look like that are the valve stem seals (in case they are whitish or very bright, but they should be dark as the night on the exhaust side, no matter what color they were when new).

Dmck · Post by **Dmck** » 18 Jul 2018, 06:59

I want to see a few more pictures of that spot. It could be an illusion and we are seeing the glow from where the valve meets the head higher up in that exhaust chamber. There is a light on the camera he is using..