My car is using about a liter of oil per 3,000km.
I assume it must be valve stem seals (it's a KJ2, and the service history shows Magnatec oil being used and from what I've read here this seems to cause this problem).

My question is, can I just keep topping up the oil or does it do some kind of damage?
The car does not smoke, not even on start up after sitting overnight.

And, for valve stem seal replacement, do the valves need to be machined or anything?
Should the heads be serviced at the same time or can valve stem seals just be replaced with no accompanying work?

I wouldn't worry about it until you get smoke on startup.
Keep in mind that burning oil will make more carbon for your oil filter to clean out, so you may want to adjust your filter change depending on the colour of your oil.

My bus has done half a million clicks (on gas mostly) and is starting to colour the oil at about 7000 Kms into the service. I am considering shortening my services back to 7.5K Kms.

Your not going to do any damage ignoring the problem.
When you have to get the seals done, they need to pull the head apart anyway. Perfect time to get valve springs checked, valve guides done and everything lapped back together.

I do 7,500km oil change intervals and use high grade semi synthetic oil (HPR 10 in there now, and next oil change which is due now will be Castrol Edge Titanium 5W40). Also considering I pour in about 2-3L of new oil throughout those 7,500km to keep the level at maximum, I assume there is no need to change oil any more regularly? Driving in Canberra there really isn't much stop/start traffic and most of the kilometers are at 80km/h.

Oil seems to be in good condition and color at the dipstick

Burning oil is different to changing oil, as the burning of oil makes things harder on your oil.

Sounds like you are really starting to burn through the oil, so it may pay to have a chat with your mechanic or local cylinder head place (if you can pull the heads yourself) about a estimate.

My local place charges about $200 per head to strip, clean, pressure check, and reassemble. Any additional work or parts are charged as needed.
Given the amount of stuffing around required to pull the heads, your looking at a few hours for your mechanic to get the job done.
Don't forget to factor in the cost of gaskets and new head bolts, as well as replacement of ancillaries. It would be a good time to do things such as the thermostat, and work on the dizzy, perhaps timing belt and water pump if your feeling rich...

Edit.
If your oil is coming out a reasonable colour, I wouldn't worry about your service interval, it sounds good enough as it is.

Is 1L of oil per 3,000km a lot to go through?

My timing belt is coming up, but at $200 a head + gaskets + OEM stem seals + head bolts, not to mention I am wondering whether I am better off doing a 6G75 conversion as it seems from a price perspective it would be similar

1L per 3k isn't that much if you have a Datsun 180B.
In a magna, that is a fair bit. You shouldn't really be using more than 1L per 10k.

If your getting your mechanic to do all the work, your looking at around $1200 from very rough figuring in my head, without knowing exactly the extent of the work needed. You could be looking at over $2k depending the extent of the head work needed, and if you factor in the extra time needed for the cam belt change.

Talk to your mechanic, see what options you have and what they'll cost you.

1L per 3k isn't that much if you have a Datsun 180B.
In a magna, that is a fair bit. You shouldn't really be using more than 1L per 10k.


Yeh as above.

My TF has 260,000km on it now, its the 3.0L Auto and that uses about 500ml of oil over the 10,000km interval.

Our Pajero has worn valve seals. Got quoted $3k for a top end rebuild in SA. Ended up getting this product called liquimolly (cannot remember what one it was, ~$15 a bottle) and also changed the oil from 15w-40 to 20w-50 and 6000km later it is just getting to the stage of needing some more oil. It used to use about a litre every 2000km

Bearing in mind, this car has done 315,000km. But after changing the oil and using this bottle, its as good as new. And the smoke out the exhaust after idle has almost ceased

If you go to mal, mitsfix or whatever, was less then half of your top end quite for valve stem seal replacement, timing belt, water pump, rear main seal, rocker cover gaskets etc etc

If you go to mal, mitsfix or whatever, was less then half of your top end quite for valve stem seal replacement, timing belt, water pump, rear main seal, rocker cover gaskets etc etc

Keep in mind I dunno if you're in vic when I say this cause my phone doesn't show that, but this was if you're in victoria

1 litre per 3000 km is nothing really. I had a TF Magna and it used virtually zero oil in 7500 km, when I changed the oil. I also had a Pajero which I was not able to break in when new. It used about 1L for the first 4000 km, then would use it at about 1L per 1000 until I changed the oil again.

For starters, I would use a slightly heavier oil and see what happens, especially with the hot weather coming on, but I wouldn't worry about your oil consumption. Oil is cheap, valve seals (or rather the replacement thereof) are expensive.

What viscosity are you currently using anyway?

Currently there is 10W50 in there (HPR10) but I am doing an oil change this week and have 5W40 already (Castrol Edge).

Will this issue get progressively worse?
At this stage it's costing me about $30 in "additional oil" over 7,500km which isn't a huge amount especially compared to a top end rebuild

No need to remove the heads to replace valve stem seals

Forget the 5-40, try 20W-50, it's cheaper. No point putting an expensive oil into a worn out engine.
It will get worse.
You could try the thicker oil and an additive to swell the stem seals.
Just keep driving that engine until a policeman tells you off. lol

Cost:
I did a Mitsu V6 head rebuild 2 years ago (burnt exhaust valve), cost $1,200 for just the parts and machine shop work. Labour was free (DIY).
Adding in a mechanic's time, a 3.8 engine might be a similarly priced option. Provided you can find a good one, of course.

If you are using oil I would say move to a thicker viscosity, and something cheaper, how many Kms on the car?

Castrol edge is bloody expensive if you have to keep topping it up, and its pretty thin.
We used to use something like 20w50 Castrol GTX or even Gulf Western when our TH was using a bit of oil, slowed it down and was cheaper to keep buying.

No need to remove the heads to replace valve stem seals

How do you manage this feat?
The valve stem seals require the removal of the valve springs and retainers so that you can slip the valve seals out - which generally means you need to be able to hold the valve into the head so you can put the springs back on. unless im missing something here....

How do you manage this feat?
The valve stem seals require the removal of the valve springs and retainers so that you can slip the valve seals out - which generally means you need to be able to hold the valve into the head so you can put the springs back on. unless im missing something here....

You sure are missing something!
Remove cam belt, rocker covers, rocker shafts.
Remove spark plugs, put air compressor connection into plug hole, pump up. Take off valve spring retainers, remove valve springs, do seals.
Move into the next.

PROs: No need to disturb head gaskets.

CONs: Not easy to do, if pressure doesn't stay up in cylinder, a valve can drop.
If not DIY, need to find a mechanic who is able to do this.
Can't check valve seating, check corrosion.

Never done it this way myself, but it is do-able in theory. Rather pull the heads and do a thorough job.

Yeh, i was considering this, but when its time for work like this i like to pull the heads and get them checked out.

Given the amount of fluffing around required to pull the heads, it is a consideration.
You can also use a leak down tester for this trick, will give you an indication as to how well the rings and valves are sealing...

I bought 3 bottles of Castrol Edge at Repco with a free oil filter per bottle for $134 all up (45% off sale) which is why I plan to use the Castrol Edge.

The car has 185,000km, and since the 200,000km service will end up being no less than about $900+ and seeing as the cost of getting the valve stem seals done will bump up the price to near enough 6G75 territory.
The car runs well, and besides the fact that I can measure the oil loss there is no clue to any problems though so since the 200K service is nearly a year away I'll consider my options then.
Are the 6G75 motors prone to any failures, ie, similar to the TJ valve stem seals?

No need to remove cam belt either madmax. Done this many times before including the verada about 2 months ago.

I bought 3 bottles of Castrol Edge at Repco with a free oil filter per bottle for $134 all up (45% off sale) which is why I plan to use the Castrol Edge.

The car has 185,000km, and since the 200,000km service will end up being no less than about $900+ and seeing as the cost of getting the valve stem seals done will bump up the price to near enough 6G75 territory.
The car runs well, and besides the fact that I can measure the oil loss there is no clue to any problems though so since the 200K service is nearly a year away I'll consider my options then.
Are the 6G75 motors prone to any failures, ie, similar to the TJ valve stem seals?

Unplan the Castrol. lol Or take it back to the shop and swap it for something cheaper and thicker.

Why not simply skip the valve stem seals and 200,000 km expense? If you do 15,000 per year and are at 185,000 km, you can easily go 3 years without either. By that time you will be wanting another car anyway, if not earlier.
The 6G75 is the same engine essentially, so anything that applies to the 6G74 as far as high km/age problems applies to that as well.

I get the impression you spend a lot of time and effort worrying about the condition of your car and asking questions about possible problems. I know it is a learning experience for you, and I guess you are finding out how much work a higher Km Magna really needs to get it into a good condition.
I've been through that process a number of times with earlier model Mitsus, and to be honest, if I couldn't DIY fixes I would not have bothered. An older Magna is a money pit, if the labour component costs money.



No need to remove cam belt either madmax. Done this many times before including the verada about 2 months ago.

Nice to know.

Interesting aside about valve overhaul: To check the valves requres that the heads come off. New head gaskets. Cannot remember how much, but probably about $100 or so for a top overhaul gasket kit. I do recall that the valve seals were expensive.

Compare that to my current ride - a 3.2 diesel Pajero. Top overhaul kit (I think it is a full kit, not just the head gasket) $789! Ouch! I hope never to see the inside of my engine....

It's called a valve regrind set (VRS), and includes all gaskets and seals needed for the job. Don't know the price, but it is more than $100.

I bought 3 bottles of Castrol Edge at Repco with a free oil filter per bottle for $134 all up (45% off sale) which is why I plan to use the Castrol Edge.


I wouldn't be using 5w anything if your valve stem seals are stuffed. If you want to waste perfectly good oil, go ahead and use it but at the rate you're going you're not going to see two full changes out of it, and the consumption issue will only worsen. Return/exchange it for 15w40 or similar (obviously the 10w50 you're currently using isn't stemming the problem) and see how the oil consumption fares.



I get the impression you spend a lot of time and effort worrying about the condition of your car and asking questions about possible problems. I know it is a learning experience for you, and I guess you are finding out how much work a higher Km Magna really needs to get it into a good condition.


This.

Remove spark plugs, put air compressor connection into plug hole, pump up. Take off valve spring retainers, remove valve springs, do seals.
Move into the next.

I have heard (from an Ultratune mechanic so you be the judge of its accuracy) that this can be tricky and prone to failure, and it's important to lock the motor (or ensure the piston is at bottom dead centre) or the pressure can turn the motor over. A trick this bloke had was to run the piston down and feed rope through the spark plug hole, as much as will fit, leaving the end hanging out so you can pull it back out. Turning the motor (raising the piston) compresses the rope and holds the valves up, allowing the seal replacement procedure to be done with the heads in-situ. Not done it myself or seen it done so not recommending it, but potentially a better/safer option than air and no air-hose/spark-thread fitting required.

So, if I am using up 300ml of oil per 1,000km with 10W50, will I use much more with 5W40?

Would it help to put some Wynns 100,000km+ oil treatment into the engine?

And seeing as it takes 3,000km to go from MAX to MIN on the dipstick, I can just fill it up twice (at 3,000km and at 6,000km) and then do an oil change at 7,500km.
Or is there another problem I am not considering?

Have done the compressed air into the cylinder trick on a number of engines, but not a V6 Magna engine. Used to change valve stem seals all the time that way, however I also say that doing an old holden six or V8 is a far cry from a 24 valve with OHC!

Personally with a high mileage motor and I have one myself that could be going that way, I would be looking at the SEAL in the Bottle and a slightly heavier oil,

As Mad Max says some times you are better off with a newer vehicle, especially if you do not have either the necessary skills to do some of this work yourselves or in fact the sometimes expensive tools!

There wouldn't be that many here who know how to operate Valve Grinding machines, RVR's, or in fact Head milling machines, and fewer still with unfettered access to them!

And seeing as it takes 3,000km to go from MAX to MIN on the dipstick, I can just fill it up twice (at 3,000km and at 6,000km) and then do an oil change at 7,500km.
Or is there another problem I am not considering?

No problems at all. Use a thicker oil and check every 1,000 km to start with.

I'm not sure if this apply to cars but it does to bikes

Find a hill, if its auto lock it in a lower gear. Roll down the hill without touching the clutch and just let the engine braking do its job, lightly use the brakes if you really need to
Engine should be spinning at a reasonable speed (3k+) with no throttle input, ideally be rolling like this for as long as you can
Then when you get to the bottom go hard on the throttle, look behind you (or have someone following you), if there's a puff/cloud of smoke then its valve stem seals
This happens because not using any throttle creates a strong vacuum inside the cylinders which slowly pulls more oil into the cylinder, without throttle input its not going to burn. When you hit the throttle now its got a lot of oil to burn = blue smoke. This is different to worn piston rings as generally thats going to smoke all the time not just under vacuum

I was told that the way to check for leaking valve stem seals is:
1. Puff of smoke upon start up after sitting overnight. I tested this and there was no smoke.
2. Let it idle 10-15 mins, then stab the throttle and see for any smoke. Have not done this but will later in the week

I was told that the way to check for leaking valve stem seals is:
1. Puff of smoke upon start up after sitting overnight. I tested this and there was no smoke.
2. Let it idle 10-15 mins, then stab the throttle and see for any smoke. Have not done this but will later in the week

Method 2 works well. My old TP would spew out major clouds when doing this. No visible smoke when driving normally - not from the driver's seat, anyway.
Warm engine, stab the throttle to 4,000 rpm, let it settle, repeat. Smokescreen time!

I'll give it a most likely over the weekend.

Guys, if I take the intake manifold off and have a look into the heads, will leaking valve stem seals be obvious?
ie, will I see some oil on the valve stem?

EDIT:
I was quoted $545 to service both heads, if I supply the heads off the car.
I suspect an additional $200 or so for head gaskets, head bolts and miscellaneous parts?
Not sure it's worth the money/effort

I was told that the way to check for leaking valve stem seals is:
1. Puff of smoke upon start up after sitting overnight. I tested this and there was no smoke.
2. Let it idle 10-15 mins, then stab the throttle and see for any smoke. Have not done this but will later in the week

Sitting at a set of Stop lights should be enough to see if your stem seals are U/S, Pull up let it idle a minute is plenty of time, ten minutes is a bit excessive and on take off see if there is a cloud of smoke behind you if there is a visible cloud behind you on take off attention should be given if not don't worry much! make sure that it is blue smoke as well and not black because that could be rich fuel less likely with Fuel injection but not unheard of! We are talking of a worn engine here several hundred thousand Kms expect some wear and expect some smoke Just not excessive smoke!

Guys,
4 pages about stem seals, really

Spetz, get the motor warm, let it idle for 15 minutes and give a good rev, dont need to thrash. If you get smoke then you have bad stem seals, if not then most likely other issues

Taking off manifolds will tell you stuff all

Yes you can replace the seals but is costly and to be honest these motors are never the same once the heads have been off

Is it a risk not doing them, if the smoke is minor (ie no issues with EPA) and you know to keep an eye on your oil level then no issues. You were using HPR10, I would use HPR15 as the fully synth 10 will go a lot faster I have found

At what driving conditions do the valve stem seals leak most, is it at idle when vacuum is high?

Madmagna, why do these motors never run the same after the heads have been off?
And, if I buy a second hand motor from you is it checked to be healthy (ie, no valve stem leaks etc)?