My '94 has been a trouper and good runner.

However, lately the 2.3L 4-cylinder smolkes blue for ~30 seconds or so when I first start it up after it sits for more than a couple of hours. It hasn't been noticeably using oil other than it does drip a tad; as a result I probably add 1/2 quart of oil every 2K miles.

So -- I'm thinking his valve stem seals may have finally gotten tired and could need replacing. Has anyone here replaced their valve stem seals in their 2.3L?

If so, was it a big job? Please tell me about your experience in doing it....

Thanks in Advance!
BarnieTrk

 

I've never replaced seals on a 2.3, but I have replaced them on other engines-usually with the head removed.. I have valve spring compressor, C-clamp type, which can only be used with the head removed..The seals themselves are not a big deal to replace, but you'll need a spring compressor that works with the head on the car, usually some kind of lever type..If I was to go through all that, I'd just pull the head, and replace the valve guides too, as with the mileage you might have on a '94, they probably have some wear, and as the new seals WILL help, new guides will make this repair even better..You can clean up the valves too, and this WILL give you better gas mileage..You can knurl the valve stems for oil control, and check the head for warping, and a new head gasket should give good compression, and no worries about the head gasket leaking or failing at some later date..BUT, if you just want to put on new seals, you'll still need the valve spring compressor just the same, and don't lose the spring keepers..

 

Oil going in through valve seals happens on intake valves. They are rubber, and when they get old they dry out or in cold weather get hard when the engine cools overnight.

Heat is transmitted from the upper chamber to the top of the head, and then to the valve seals. When things get hot they expand.

(with me so far?)

When rubber is cold, it hardens. When it warms - it becomes pliable (more elastic, and able to seal). When the valve seals are cold and the valve guides warm it stretches cold seals. The elasticity of the seals when cold determines how fast they wear out.

So it seems to me there are two stages of oil seal failure at the valve stem.

Intermediate elasticity failure, where warm up is required for them to seal.

FINAL FAILURE when they are so dry they crack....

The "GARTER SPRINGS" around them I wouldn't worry about. The rubber the seals are made out of are the question. When the rubber boots go to hell they leak all the time, because they have had cracks form in them during warm up. At that point they are just plain gone....

It is best to catch them when oil smoke is seen on warm up, but you can run such an engine until the smoke is around for a longer time after it reasonably SHOULD HAVE been getting warm.

Either way BE DAMNED SURE WHAT YOU ARE DOING when replacing valve seals, so that you don't drop a valve into a cylinder with the head on.

It can be done - but if it messes up you have to take off the head.

A fitting that allows an air compressor to put 100 PSI of pressure in the cylinder through the spark plug hole is the old time way.
If the valve drops - it was burned anyway.



OFF WITH THE HEAD!

*If you really want to do it right anyhow, you'll pull the head and check the deck of the block for straightness. Cast iron can warp.
Not as fast as aluminum, but it can.

WHENEVER YOU DON'T KNOW IF THE ENGINE HAS BEEN OVERHEATED don't trust the block and head planing.

The same is true of the align-bore of the center mains and cam galley. -In fact even more so. A crooked block will tear everything to pieces

 

Well Fellas,

Sounds like the consensus is I should NOT just change out the valve stem seals, but rather the smarter move would be to remove the head to allow a head shop to re-work the valve guides as they are likely tired as well. Worn valve guides would likely allow excessive amounts of oil to get to the seals, more than they would be 'happy' with.

By removing the head, I could likely do a better job of de-carbonizing to combustion chamber than by dumping in some 'seafoam' or such. The head shop could also inspect the valves and valve springs for any major issues.

I'm plenty hesitate to NOT go so far as to ask the shop to do a valve job, as that may tighten up the top side of the combustion chamber enough to cause excessive 'strain' on the tired original piston oil rings; which would likely encourage oil blow-by causing another issue/problem. This ol' 2.3L turned over 291K miles last week, so it's on the tired side.

I will likely also use this opportunity to change out the timing belt as it is WAY past due to be changed. I will also change the water pump, thermostat and serpentine belt, since I'm right there. I just changed the serpentine belt tensioner not too long ago, so that would likely stay.

A needed parts list would likely include:

- Head gasket
- New set of head bolts
- intake/exhaust manifold gasket
- valve cover gasket
- sepentine belt
- timing belt
- water pump
-antifreeze, motor oil & filter, sparkplugs

I would likely buy the valve stem seals and the guides from the local cylinder head shop and have them installed there. I'd also ask them to check the block and intake/exhaust surfaces for straightness and ask them to inspect the valves and valve springs.

(I do have a Haynes manual..... now if I can just locate that baby! )

What am I forgetting, Guys?
BarnieTrk

 

A lot of shops put on new springs when you have higher mileage, but that's where it gets pricey-see if they can test the old springs..If they are a good head shop they have the tools to do this-and tell them to only replace "really worn" valves($6-10 apiece),and to not "three angle" the valves(boosts compression, but costly), and to clean the seats, and only rework the ones with excessive wear(pitting/scarring from old valve)-tell them you want a "low buck" valve job, and explain in detail want you want, and also ask them if they "throw in" a pressure check(water jackets) as part of the service...Your parts list is good but, throw in upper and lower radiator hoses, and check out heater hoses while you're in there, and replace any accessorial "V-belts"(if any), along with the serpentine.. Good Luck!!!

 

Get a new Radiator cap too - and look all around for leaks and drips.

But I will SPECIFICALLY NOTE one place to worry about a leak that you will have a hella time to get at once the head is back on:

There is a steel line that runs down the passenger side of the head to the back and around the back to a manifold heater connection (it heats the floor of the intake manifold). It is joined to the manifold by a short length of rubber tubing, about two inches long. THAT piece of tubing needs to be brand new when you put it back together.

Trust me....

 

Good Point, DRB..... I will ask the head shop to simply shim the springs if they need a little 'tightening up' rather than replacement. Also a good point on a standard 'low buck' valve job instead of the more expensive 3-angle job. Radiator & heater hoses would likely also be smart. In fact, this may even be the time to replace the radiator too. No other belts but the sepentine one.


10-4, Graywolf........ Thanks!


Thanks for everyone's input.
I really do appreciate it!
This site ROCKS!!

BarnieTrk

 

Quote:
It hasn't been noticeably using oil other than it does drip a tad; as a result I probably add 1/2 quart of oil every 2K miles.

Did you know that you are using less oil than what would be acceptable by Ford when your truck was new? Using one quart in 600 miles, not 1/2 in 2,000, is the limit before Ford will do anything. At least it was when my truck was new. I and my friend bought trucks at the same time. His ate oil. He had to document every drop of oil and mile driven. Their statement was that 1 quart in 600 miles was acceptable oil consumption. His ate more.
You are worrying over something you should just let be. My truck uses that much oil, and has done so since new. I end up adding 1/2 quart and then it will be good until just about time for an oil change.
Save your money for a new truck, unless you want to tear into it. If you spent $100, and quit burning oil completely, and oil was $4/quart, you would have to travel 100,000 miles to break even.
1/2qt/2000= 1qt/4000, $100/$4 = 25 quarts. Do you think you will spend more than $100? Will your gas mileage improve to help pay for the job? I can't answer, but I know I am keeping my truck as is, and it burns about what yours does. And it is almost 10 years older.
tom

 

I don't agree, I just don't agree (with posts previous to Tom's)! Can someone explain to me why an engine that simply puffs a little smoke on startup needs a complete head re-work? And why, since you're going to that much trouble anyway, you wouldn't just go ahead and completely rebuild the motor? Get a fitting, pressurize the cylinder, change the seals, spend $30 on seals and a new valve cover gasket, and be done with it in a weekend. Unless you plan on keeping this truck for the next 30 years of your life, there's no reason to re-work the engine like it's a classic car that has to be perfect! Stem seals get old and hard, most of the time long before the engine needs any other work. Unless you are seeing signs of other trouble, it seems to me that pulling the head and having it re-worked is just a way to spend more money. I'm all about doing the job right, but the deeper you dig, the more you spend, and you don't need to look for problems you're not having!

 

Tom,
I hear what you're saying..... but -- it's not just about the amount of $$ spent on oil. Yeah, a few dollars worth of oil every 2K miles or so isn't a big deal. However, I know that if the oiling gets worse, it will shorten the life of my plugs, it will put a strain on my old, tired coil packs that will be trying to fire the oily plugs at startup, and it makes an ugly smog every time I start it. The starting ability will simply decrease.


BSmitty,
Since I've never worked on an OVERHEAD CAM engine, which is what this is, can I replace the valve stem seals WITHOUT having to mess around with removing the camshaft? I assume I can locate a valve spring lever to remove the keepers/retainers, springs to get to the seals. If I can't locate the gear to pressurize the chambers, I'll go with some cord in the plug hole to keep the valves from dropping. I agree, a classic this isn't!!

BarnieTrk

 

If it doesn't smoke when you let off the gas going down hill then it probably doesn't need valve stem seals or rings. The puff of smoke can be from the pcv system fuel injector leakage etc etc. Your oil consumption is really low considering it has an external leak. If it is running fine I would just leave it alone. Kinda of don't fix it if it isn't broke. And yours doesn't sound like it is broke. If it truly burning a lot of oil it will eventual show up on the spark plugs as to which cylinder(s) are using oil.

 

If and when you go to work on the 2.3, get a thick pair of gloves as there are more sharp edges on that head than you care to find. You will need a lever type spring compressor, and something to push the cam follower out of the way, off the top of the valve stem and off the top of the lifter. It is one of those jobs where you are looking to keep your fingers out of the way of sharp and metallic objects for fear of squishing them or taking chunks out.
I used an old valve spring compressor that had a reversible hook on the end. It has been quite a few years, but I remember doing something where I turned the hook upside down, or changed how it was bolted to the arm/lever part of the compressor. Keep the followers in the same position when you reassemble as they are just like lifters in their 'relation' with the cam lobes.
I still vote for a delay - at least until it is warm outside. And proceed only if you are getting spark plug fouling. Mine doesn't foul plugs, and uses about the same.
tom

 

TomW and WTRoger,,,, thanks for the replies and advice!

Fellas,
It's weird,,,,, now for the past few days it hasn't puffed blue at startup. It has also been warmer outside, like in the teens to mid 20s.... not the 5*F to sub-zero temps it was a week or so ago. Could the blue puffin' be related to the cold????

Tonight I pulled each of the plugs (on the exhaust side of the head) and they all looked just fine... almost too light, near white. Since they are the non-platinum Autolite 764s I expected their gap to be wide...and it was. I reset their gap to 0.042", dabbed a bit of grease on their threads and a dab of dielectric grease smeared on the boot end of the plug and re-installed them.

I think I'll follow your suggestions and simply leave it intact for now and just monitor the oil level (as I normally do) and watch for any more blue puffs when starting or when "I'm letting off going down a hill".

I'll copy this thread and save it in my electronic BarnieTrk records for possible future use and/or reference.

A BIG THANKS to everyone who shared their thoughts, ideas, suggestions, and experiences! This really is a GREAT site!

BarnieTrk