Help Me! 850 T5 Head Removal

[JosLozVolv]

Hello Everyone!

So I have a 95' 850 T5 (193k on clock closer to 260k when asking previous owners how far they drove it with a broken odometer) that's burning alot of oil.

Symptoms - Alot of smoke when cold at idle and when on throttle dies down a little after it's been running

The previous previous owner thought valve stem seals. Anyways I need help with the following.

1- Anything else to check before doing valve stem seals?
2- Anything else to look out for when doing the seals?
3- I have no experience with head off work so basically how hard is it and how badly can it go wrong if you're not careful?

Thanks for any help or advice!

[ITSv40]

Originally Posted by JosLozVolv

Hello Everyone!

So I have a 95' 850 T5 (193k on clock closer to 260k when asking previous owners how far they drove it with a broken odometer) that's burning alot of oil.

Symptoms - Alot of smoke when cold at idle and when on throttle dies down a little after it's been running

The previous previous owner thought valve stem seals. Anyways I need help with the following.

1- Anything else to check before doing valve stem seals?
2- Anything else to look out for when doing the seals?
3- I have no experience with head off work so basically how hard is it and how badly can it go wrong if you're not careful?

Thanks for any help or advice!

1. Carry out a compression test before anything else - this will give you a good indication of the state of the pistons and bores.

2. If the bores and pistons are ok and there are no broken rings the fault will lay in the head. Most likely worn guides that will need replacing, possibly new valves and seats re cut. Certainly new seals and the head will need skimming before refitting.

3. If you have changed a timing belt in the past the head should be do-able. If you have not ventured to a timing belt I would leave it for others. Only you know how competent and comfortable you feel with the spanners.

If you do tackle it: read up/watch Utube beforehand, take your time and work methodically and take plenty of photos while dismantling.

A multitude of other things like new head gasket kit, head bolts, new timing belt and tensioner, but these are all part and parcel of the whole job.

[JosLozVolv]

Originally Posted by ITSv40

1. Carry out a compression test before anything else - this will give you a good indication of the state of the pistons and bores.

2. If the bores and pistons are ok and there are no broken rings the fault will lay in the head. Most likely worn guides that will need replacing, possibly new valves and seats re cut. Certainly new seals and the head will need skimming before refitting.

3. If you have changed a timing belt in the past the head should be do-able. If you have not ventured to a timing belt I would leave it for others. Only you know how competent and comfortable you feel with the spanners.

If you do tackle it: read up/watch Utube beforehand, take your time and work methodically and take plenty of photos while dismantling.

A multitude of other things like new head gasket kit, head bolts, new timing belt and tensioner, but these are all part and parcel of the whole job.

Okay great just one thing now

1- If compression is low what then? Don't bother?

I'm fairly confident but could be false confidence ahah. I've had a 306 rallye for a year and I've replaced the rear axle, brake lines flexi and solid ones, had most of the front end apart cleaning up rust, fitted new radiator, but I've never tackled any engine jobs I feel like I could do it if I take my time and just make sure I'm doing everything right. Dad's a hgv mechanic so he can always jump in and help if I get stuck my main worry is timing it wrong when I get it back together and making it worse than it was before I started ahah.

Thanks for the reply btw

[ITSv40]

Originally Posted by JosLozVolv

Okay great just one thing now

1- If compression is low what then? Don't bother?

I'm fairly confident but could be false confidence ahah. I've had a 306 rallye for a year and I've replaced the rear axle, brake lines flexi and solid ones, had most of the front end apart cleaning up rust, fitted new radiator, but I've never tackled any engine jobs I feel like I could do it if I take my time and just make sure I'm doing everything right. Dad's a hgv mechanic so he can always jump in and help if I get stuck my main worry is timing it wrong when I get it back together and making it worse than it was before I started ahah.

Thanks for the reply btw

With a compression test you are looking for even pressures. I'm not sure what you would expect on your particular engine, but generally around 140 -150psi is normal. If you only get say 115 -120 psi that would be a good indication that all bores/pistons are worn and the engine needs a re-bore and new pistons and infact a complete rebuild. If say you get 140 or thereabouts across four cylinders, but only 120 on the other one, it would indicate that there is a problem in that cylinder. Could be a broken ring/scored bore or the valve not seating/sealing correctly due to wear. In that case you would at least know which cylinder to focus on once the head was off and depending on what was found know how to resolve.

My son recently had a problem with his V50 T5 - loosing water and spewing oil out the back of the engine. Did a compression test and found No 5 cylinder was way down on compression. Took the head off and sent it way for inspection and overhaul - there was a hairline crack in the head between the water jacket, oil gallery and exhaust port which affected compression and let both water and oil escape. The head was basically b*ggered - the machine shop thought it was a casting flaw, rather than something caused through running the engine.

You are going in to the unknown, but with a little testing you can narrow the unknown down to likely possibles. As for financially viable, only you know how much the car is worth as it stands and how much time and effort you are prepared to put into it.

[JosLozVolv]

Originally Posted by ITSv40

With a compression test you are looking for even pressures. I'm not sure what you would expect on your particular engine, but generally around 140 -150psi is normal. If you only get say 115 -120 psi that would be a good indication that all bores/pistons are worn and the engine needs a re-bore and new pistons and infact a complete rebuild. If say you get 140 or thereabouts across four cylinders, but only 120 on the other one, it would indicate that there is a problem in that cylinder. Could be a broken ring/scored bore or the valve not seating/sealing correctly due to wear. In that case you would at least know which cylinder to focus on once the head was off and depending on what was found know how to resolve.

My son recently had a problem with his V50 T5 - loosing water and spewing oil out the back of the engine. Did a compression test and found No 5 cylinder was way down on compression. Took the head off and sent it way for inspection and overhaul - there was a hairline crack in the head between the water jacket, oil gallery and exhaust port which affected compression and let both water and oil escape. The head was basically b*ggered - the machine shop thought it was a casting flaw, rather than something caused through running the engine.

You are going in to the unknown, but with a little testing you can narrow the unknown down to likely possibles. As for financially viable, only you know how much the car is worth as it stands and how much time and effort you are prepared to put into it.

Brilliant thank you so much!

[Luxobarge]

Hang on a mo - before you start ripping the head off, how about the turbo? Worn turbo will cause quite a bit of smoke, but I'm not totally sure how you diagnose that it's this rather than valve seals, bores etc. but others on here may have some ideas. You'd be gutted if you pulled off the head, then put it all back together and found it was just as bad due to worn turbo seals.

Also worth noting - I had quite a bit of smoke on my T5 after idling for a while, and thought it might be stem seals or turbo. However I reckoned it was also due a PCV system change/clean, so I did that and the smoking has totally stopped - so make sure your PCV system is good before doing anything else would also be my advice.

If it is stem seals, it's possible to change them without removing the head, it's fiddly but do-able. You need to remove the camshafts and feed rope (sash cord is good) into each cylinder in turn with the piston at the bottom of the stroke, then rotate it until the piston crushes the rope against the valves. This will stop them dropping, so you can remove the springs and replace the seals. Just thought it was worth mentioning. Your call as to what method you want to take of course.

Hope this helps!

[JosLozVolv]

Originally Posted by Luxobarge

Hang on a mo - before you start ripping the head off, how about the turbo? Worn turbo will cause quite a bit of smoke, but I'm not totally sure how you diagnose that it's this rather than valve seals, bores etc. but others on here may have some ideas. You'd be gutted if you pulled off the head, then put it all back together and found it was just as bad due to worn turbo seals.

Also worth noting - I had quite a bit of smoke on my T5 after idling for a while, and thought it might be stem seals or turbo. However I reckoned it was also due a PCV system change/clean, so I did that and the smoking has totally stopped - so make sure your PCV system is good before doing anything else would also be my advice.

If it is stem seals, it's possible to change them without removing the head, it's fiddly but do-able. You need to remove the camshafts and feed rope (sash cord is good) into each cylinder in turn with the piston at the bottom of the stroke, then rotate it until the piston crushes the rope against the valves. This will stop them dropping, so you can remove the springs and replace the seals. Just thought it was worth mentioning. Your call as to what method you want to take of course.

Hope this helps!

Thank you!

I've no experience with Volvos other than what i've read on the web and what the previous owners told me about. And he seemed very knowledgeable and had changed the PCV system a little over a year ago probably around 40k ago ish, so is this worth a look at? They also had it burning oil the whole of there owner ship which makes me think they know what they're talking about when they suggest valve stem seals.

Is their any good guides on diagnosing a bad turbo or is it as simple as looking for oil around the turbo?

[doingitsideways]

Does sound like bad stem seals.

Turbo seals tend to smoke more on boost than just pottering around and/or idle.

Do a compression test as suggested.
If any cylinders are a bit low, put about a teaspoon of fresh engine oil down the spark plug hole then retest.
If the pressure notably increases, that would indicate bad piston rings.

[Rooster]

23 year old car its likely stem seals have gone brittle and due replacement,

If you pull dipstick out with engine running when its warm it will give you an idea of how heavy engine is breathing,

Have a look under car see if you can see any oil residue on intake side of turbo feed pipe,

The engines arn't rocket science to strip but a good read of a manual might be an idea especially if you have never tackled anything like this before,

Maybe if you can find a fellow volvo owner locally who might be able to lend a hand,