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When changing head gasket is it necessary to also change the valve stem seals ???

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It is not strictly necessary on most cars if the engine has not been burning oil from worn seals there. On some newer cars gaining access to these seals can be quite difficult even after lifting the head. On others it is much easier. Then on some engines like Hyundai Excels you virtually have to because it is such a weak spot.

So if you can without too much trouble it is a good idea.

Posted on May 19, 2017


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Posted on Jan 02, 2017


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Cost to rplace head gasket for a 1994 t100 toyota

There are too many variables to be considered meaning it isn't possible to provide a quotation.

Head gasket replacement is never a routine job and it is only possible to decide what actions are necessary and what are desirable after the cylinder head has been removed. It is not a task to be hurried and other work is likely to be necessary in order to provide long term reliability and good value, the cylinder head gasket face will probably need resurfacing for instance and typically there will be much cleaning and truing needed to produce a satisfactory finished job.
It is also usual to change the engine oil and filter, fit a new thermostat and fill with new coolant...

It might be found desirable to resurface the valves or simply just replace the valve stem oil seals. Unless replaced very recently the timing belt should also be replaced...
There is also price differences between OE parts and pattern parts to consider.

If the head gasket failed completely, the oxygen sensor and CAT might also need replacing, though it is impossible to check these until the engine is running again.

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How do I change valve stem seals on a Skyteam ST50

This is not a "drive way" repair... you need to do one of two things.. sometimes you can get a connector that can replace the spark plug to keep air pressure in the cylinder (THAT CYLINDER MUST BE AT TOP DEAD CENTER ON THE COMPRESSION STROKE!!!!) that will keep the valves closed..( YOU MUST HAVE A LARGE HIGH PRESSURE-HIGH FLOW AIR COMPRESSOR!!!) you can remove the valve springs one at a time (have a way to compress the springs??) ..and replace the valve stem at a time.. IF you DO NOT have the tools to accomplish this, --- YOU CAN REMOVE THE HEADS.. hold the valves in place and remove the valve springs.. and then change the seals, you must have a valve spring compressor to accomplish this.
Does this seem like something you can do..?? If you have never done this??.. PLEASE just pay a qualified professional to change them!! You will need intake gaskets, head gaskets, valve cover gaskets, valve stem seals.. maybe the valves will need re-seating..
just to name a few things... get the idea...

Sep 25, 2017 | Cars & Trucks

1 Answer

2002 Subaru impreza ts 2.5 when driving down the road and let off the gas and coast then get back into it it smoke bad for a few minutes then clears up until you coast again. Is it the head gasket

when you are coasting , the inlet manifold vacuum can exceed 25 " mercury and that puts extra strain on the valve stem seals and rings
if they are failed or the valve stems guides are worn then the vacuum sucks oil past the seals and down the valve stems into the combustion chambers , resulting in the smoke when the system again fires up on acceleration
find an accrdited service center with experience on the make of car, have them do a compression test (wet and dry) to determine engine condition and if the rings prove a good compression , then they will be able to change the valve stem seals with out removing he head/s
get quotes first

May 19, 2017 | Subaru Cars & Trucks

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How to replace the head gasket on an 86 FORD BRONCO

A torque wrench to tighten the bolts to spec. Necessary tools to remove the head bolts. A gasket scraper for the rocker cover gasket and the head gasket.. If you have a blown head gasket the chances of a warped head is about 98%, so be prepared to have the head machined flat before reinstalling the head. You might want to do a valve job and replace the valve stem seals since you're going to remove the head. If you decide to do a valve job, you MUST do both heads or the engine will never run good.

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How to replace the head gasket on a 2004 Chevrolet Colorado

Your heads may not have to come off, you have worn valve stem oil seals, some mechanics have the gear to change your stem seals without removing your heads, this is a massive save in labour costs

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1 Answer

Black and blue smoke when cold start

Hey Anon..this is a serious problem ONLY if you do not keep your engine oil level full...but you do need to get it repaired as soon as you can..
Sounds like you may only need new valve stem seals...BUT.. you need to check and see if your car smokes when driving.. especially when you are stopped at a red light, then take off again...Does it smoke then.>??? >> THIS IS IMPORTANT!!... It determines whether its rings and/or valve stem seals.. If it smokes after a red light.. it could be rings and valve stem seals.. If it ONLY smokes in the morning.. its a 99% chance its just worn out valve stems seals...
Find a qualified professional (ASE Certified or Toyota Factory shop) ..This is NOT an inexpensive fix..BUT - ASK if they will replace the valve stems seals without removing the heads..( I KNOW they can..its just a matter of WILL they!?!?)...BUT....The shop will want to rework your head(s).. called a "valve job" and this is normal,-- they will remove the head(s), all the valves, regrind their sealing surface and regrind the valve seats in the heads, install new valve stem seals, new intake gaskets, new head gaskets, fresh antifreeze..(get a new -QUALITY- thermostat and have them install it - no need to chance overheating your engine), they should "surface the heads".. giving them a fresh gasket sealing surface.. this will restore the sealing surfaces and help with the compression, and I would recommend letting them do it if you can!!....if you do this -- MAKE SURE you ask/demand for ALL your old parts back,-- all of them!! Good luck,, please mark as/if helpful...thanks!!

Sep 10, 2017 | 2006 Toyota Camry 2.4

1 Answer

Dark water coming out tail pipe when I start my 1993 Saturn sl1

Oil in a cylinder is never good. There are several ways for the oil to get there and different prices to fix it.

Valve stem seals go directly around the valve and keep oil from the valve train from entering the combustion chamber. A worn or cracked seal can let oil run into the wrong place. Depending on how the camshaft and valve lifters are fitted, the valve stem is at the bottom of the camshaft and lifter. The overhead Cam models bury to valve stem deep inside the head.

Good practice would be to replace all seals at same time, but 1 cylinder could be done independently. But you are usually doing 90% of the work to do 1 set of seals. If a V-6 engine do the bad bank completely.

Head gasket, oil circulates through passages. Requires removal of everything above the head so gasket can be changed.

Bad Oil ring on Piston. Requires removal of head, oil pan, possibly motor to access crankshaft.

There are some tests which can help tell the difference between the problems. Some of it is visual so you need some disassembly for that. This is not going to be as simple as changing a waterpump or an Alternator. But the valve stem seals are reasonable and the head gasket is not so bad.

Can not say what labor will cost, but it will be probably 80% of the bill.

Oct 20, 2012 | 1993 Saturn SL1

1 Answer

Suspect valve stem seal caused smoking after being idle, replaced head gasket set and p'rings,t'belt, plugs, oil & air filter as there was no service history at 66,000 miles. fired up fine...

If it only smokes after you crank it up and then stops after it warms up usually that is the valve seals letting oil leak down in the cylinder after you cut it off .

Jul 03, 2011 | Daihatsu Charade Cars & Trucks

2 Answers

1993 TOYOTA TERCEL 1500cc Valve Seals Replaced now smokes much worse

You either have had the wrong valve seals installed, they are physically missing, or the valves are incorrect (too loose in the guides/stem too thin). The rocker arm seals will not contribute to your issue. If it did not have the oil smoke before you took the head off, the issue is with whatever the machine shop did. Valve seals have to fit TIGHT, or oil will go down the valve stem into the intake.
Take the head back to the machine shop & tell them to fix it. For free.

Aug 23, 2008 | 1993 Toyota Tercel

1 Answer

My mx3 just had the head done and it is still blowing blue smoke once a day when i first start it... the mech that did the head said the compression was done and good and that when they opened the head...

Sounds like the excuse is a load of BS to me. If that was the case, the oil would of been burnt off during the normal test drive after they completed the head. I'm assuming you had a blown head gasket?

Blue smoke is indeed oil and if it ONLY occurs at start up then clears itself after some driving, it's the valve stem seals or valve guides (but more likely the stem seals).

They were most likely not replaced during the overhaul.

The stem seals stop oil from the upper lubrication in the head travelling down the valves into the combustion chamber and burning with the fuel.

While the engine is running, there is enough movement in the valvetrain (all the bits that move the valves) so that oil cant make it down into the combustion chamber.

However, when the engine is stopped and left for a period (ie: overnight) oil can trickle down into the combustion chamber through the seals which is why when you first start it up the next day it blows blue smoke. All that gathered oil in the combustion chamber is burning off.

The reason why they probably haven't changed the seals is simple: they make more money.

As a mechanic doing a head you have 2 options: You can either get what's called a 'Headset' which is the head gasket with all the other gaskets involved and stem seals OR you can buy the head gasket by itself and reuse the old gaskets and not replace the stem seals.

The head gasket by itself is half the price of the Headset but you can still charge the customer for the full headset....see where im going? Trust me, this kind of practise is unfortunately very common and one of the reasons I got out of the industry.

Once a car overheats due to a head gasket or any other problem, the stem seals nornally always have to be replaced because they harden due to the heat and lose their sealing power.

The solution? The head has to come off again to replace the seals and these guys probably know it so they are going into BS mode to protect themselves.

You have to insist they fix the problem because it wont go away and don't back down!

Oh, and for future reference there are only 3 kinds of smoke you can get:

Blue = Oil burning
White = Water burning (pretty normal in the morning)
Black = Fuel burning (Mixture running too rich)

Hope this helps :)

Jul 14, 2008 | 1994 Mazda MX-3

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