is it necessary to remove the valves and springs when servicing blown cylinder head gasket?

Question

I'm working on getting the cylinder head gasket removed and replaced with a new gasket. However, in the manual, it says the valves and springs needed to be removed. Since I'm not servicing the valves, do I really need to remove the valves and springs??

Answer 1

That's a loaded question!

If you have a blown gasket, chances are you will have a warped head, especially if it ran hot. Maybe not, I have seen them not warp, but my guess is 75% of the time the heads are warped. Surfacing MAY fix it, but it may not. Be extreemly certain yours is not warped.

If you do a valve job on that head, it may cause oil blowby in the lower end, may not, but there are a lot of factors involved there (mileaga, condition etc.)

If you plan on re-using the head "as is" you may want to consider at least replacing the valve seals. Now is the best time to do that, and the springs have to come off. The valves should be left in the same places, but you can remove the one at a time and clean the carbon.

If you are just trying to get by the cheapest way, just replace the gasket and hope for the best.

Answer 2

First make sure it is definitely a blown head or gasket. If there's coolant in the oil or oil in the coolant or coolant getting out without any external leaks, then the problem is probably around the head somewhere. As long as there's no coolant in the oil, you could try removing the radiator cap and trying to start the engine. In a worst case, you'll see water blow out of the radiator (I've seen it happen). If it's a small problem, then you'll see lots of bubbles in the radiator coolant when the engine is running. You could also test the compression of the cylinders to confirm that there's a leak if none of the above things happen. I wouldn't recommend any products that say they can repair a blown head gasket without physically removing the gasket and replacing it. You can easily change the head gasket on most cars without removing the engine. On horrizontally-opposed engines (like what's used in Subaru's, VW's, Porsches, and maybe some other cars), you might have problems getting the head off because of the clearance with the side panels or chassis rails. Also with some light trucks and vans that have cast iron heads, you might need a friend to get the head out because they can be heavy. I recommend having a a workshop manual (like a Gregory's manual) for the car so you have instructions on what to do and what to watch out for. Also have a heap of small containers (I use christmas pudding containers which I found on the side of road) to put the parts in and lots of small pieces of paper to label the containers. A digital camera is also useful for taking photos of the parts as you remove them in case you need to see how they go back on, and a voice recorder/ notetaker is good to take notes on how the parts were arranged and where the hoses, etc were connected. This all might sound like overkill but I've repaired a lot of cars and have learnt these things from my mistakes. Read through the workshop manual first before starting to buy anything else to see if there's anything there that you think you might have trouble with. There are tools that you will need including a decent (accurate) torque wrench which is probably the most expensive tool. I recently bought a Kincrome one and it's accuracy is tested by hand and it looks like a good one. You'll need to buy the new head gasket, intake manifold gasket, possibly an exhaust manifold gasket, rocker cover gasket, and so on before you start. Sometimes you can get these as a head gasket kit. You'll also need head gasket sealer (preferably one that can also be used on the intake manifold if possible), and exhaust gasket sealer. If it's an EFI engine (has computer that controls engine), then see if you can get an exhaust gasket sealer that is safe for oxygen sensors because oxygen sensors are expensive. You'll also need a wire brush and a can of something like RP7 for the exhaust manifold studs as these can be a real bi*ch to get off. I found that a brass brush for a drill works good and take your time with these because it's very hard to remove a snapped stud. Try lightly tapping the end of the stud with a small hammer while putting pressure on the nut with a ring spanner. You'll also need the standard tools like socket set, full set of combination spanners (or a set of ring spanners and set of open-end spanners), screwdrivers, feeler gauges, etc. There's one other main thing to remember. If you don't want to replace another gasket within a few months, get the head shaved. This makes sure the head is completely flat. Also, as you put everything back together, make sure you tighten the head bolts in order like it says in the manual (and sometimes they need to be removed in order too). You should also check the valve clearance once you put the rockers back in. The manual will tell you how to do this. Remember to make sure the camshaft pulley or sproket is in the same rotation position as when you took it off or else you could damage a valve or piston. The manual should explain this too. You might also have to retorque the head bolts after a certain number of kilometers and if the car has done a lot of kilometers and you don't know when the timing belt or chain was last replaced, you should look into doing this at the same time.

Answer 3

No, you do not have to remove the valves to replace a head gasket, but you will get a lot better seal if oyu have a machine shop surface the head. If you have the money it is a good time to replace valve seals, though. Most machine shops will want to remove the valves when they surface the head.

Answer 4

I don't see any need for you to have to break down the springs and valves. The only reason you would have to do that is if you would have the head planed if it was needed, which could happen if you blow a head gasket, especially with the aluminum heads.

Answer 5

No, It's not necesary but since you have the head off why not.just make sure that the head is not bent or cracked around the valves and the valves are not bent.Good Luck!

Answer 6

It would help to know what kind of vehicle you are working on. I've never heard of any vehicle you had to do this to replace a head gasket.

Answer 7

valve springs are connected to the head you do not have to pull them off unless you are replacing your valves or them.

Answer 8

unless your working some high tech millitary **** how the hell would you get the valves out with the cylinder head still on the engine?

Answer 9

no it is not necessary but if you have the head(s) have them checked to be sure that it isnt worped or cracked

Answer 10

WHAT KIND OF VEHICLE