Author Topic: Head gasket replacing (Read 5051 times)

ejust · « **on:** August 07, 2005, 06:24:00 pm »

Curious here..but if i change my head gasket (i think its leaking due to oily in the coolant) whats the fastest easiest way.

I was thinking as such:

turn engine as is to TDC
undo timing belt cover and timing belt
undo any hoses to cyl head
undo Inj pipe from inj and pump
remove valve cover and splash guard
drain coolant
undo cyl head bolts
lift up carefully and pull out old gasket
make sure surfaces are clean and slip in new one with same thickness
reverse the procedures above torqueing per bentley

i dont think exhaust or intake should have to be bothered with right? let me know..thanks

chrissev · « **Reply #1 on:** August 07, 2005, 06:42:46 pm »

Quote from: "ejust"

Curious here..but if i change my head gasket (i think its leaking due to oily in the coolant) whats the fastest easiest way.

I was thinking as such:

turn engine as is to TDC
undo timing belt cover and timing belt
undo any hoses to cyl head
undo Inj pipe from inj and pump
remove valve cover and splash guard
drain coolant
undo cyl head bolts
lift up carefully and pull out old gasket
make sure surfaces are clean and slip in new one with same thickness
reverse the procedures above torqueing per bentley

i dont think exhaust or intake should have to be bothered with right? let me know..thanks

hah, funny. i have some time so I'll answer this one. You have to clean the cylinder head and engine block very well. Both surfaces need to be spotless. It takes hours to do and is the worst part of doing a headgasket. The cylinder head is the hardest because you have to be careful not to scratch it (aluminum is really soft). Engine block is a bit easier because it's cast iron. There will be crap on both surfaces and it will come off as dust which will fall into the cylinders if you don't plug them up with rags. Even then you have to vacuum them out when you are done scraping and cleaning. You also have to look carefully at both surfaces because though they may look smooth, there will be stuff on there that will scrape off if you try scraping it. This will be more true of the engine block than the cylinder head. The valves will be most likely crusted in carbon so much that you might not be able to even make them out as valves. This of course all has to come off. The cleaning is the hardest part of the job. Why I hate doing head gaskets. So, to answer your question no, you can't just slip the old gasket out and slip a new one in it's place. It won't seal and you'll have to do it again.

dubCanuck1 · « **Reply #2 on:** August 07, 2005, 08:46:54 pm »

So, since it's such a pain in the @$$, wouldn't it be worth it while you're in there to do the whole engine? How much extra work would that be?

ejust · « **Reply #3 on:** August 08, 2005, 02:41:06 am »

i would do the whole engine but i dont have the funding for it. So a new gasket will have to do until then

Patrick · « **Reply #4 on:** August 08, 2005, 03:05:21 am »

You got all the steps, just remember new head bolts. Last one I pulled apart wasn't nearly as dirty as chrissev described, if there hadn't been other damage (prechamber cup came loose) I would have figered 1/2 hour cleanup tops. Have also seen the opposite though! You won't know how bad the cleanup is going to be until you get in there. Have fun! :lol:

chrissev · « **Reply #5 on:** August 10, 2005, 06:09:14 am »

Quote from: "ejust"

i would do the whole engine but i dont have the funding for it. So a new gasket will have to do until then

It doesn't cost very much to put new rings and bearings in, and it makes a huge difference to freshen up a tired engine that way. It's not the same as completely rebuilding the thing but you will notice a difference in performance and also possibly oil consumption. For the cylinder walls you just lightly buff them up with some fine grit sandpaper to remove the glaze and you are done (you can use a drill to do this).

ejust · « **Reply #6 on:** August 10, 2005, 09:45:08 pm »

ive got a brake cylinder hone..would that work ?? How long does a quickie rebuild usually last?

And what can i do about my oil pressure being at 10psi at idle warmed up?

chrissev · « **Reply #7 on:** August 10, 2005, 10:08:22 pm »

Quote from: "ejust"

ive got a brake cylinder hone..would that work ?? How long does a quickie rebuild usually last?

you don't want to hone the cylinders. Just buff them a bit. You don't want to take any metal off otherwise you'll be buying oversize pistons and they are not cheap. A block of wood cut to the right size, covered in sandpaper and attached to the end of a drill will do the job quite well. Not sure about a brake cylinder hone. They remove the metal from the brake drums don't they?
Re: how long will it last?: depends on the condition of the cylinders and the condition of the crankshaft and the intermediate shaft bearings. If the crankshaft is worn then new bearings won't help any. Also you can't replace the intermediate shaft bearings unless you take the engine out of the car so if they are worn then that will be an issue. With the cylinders, sometimes when they are really worn they become oval shaped. If this is the case, buffing them won't do anything and you need to make them bigger to get them round again, and then fit oversize pistons. If they are still pretty round but just covered in glaze then buffing the glaze off them and fitting new rings will really improve the engine's compression and cut down on oil usage.

Quote

And what can i do about my oil pressure being at 10psi at idle warmed up?

maybe a bearing problem?

Centurion · « **Reply #8 on:** August 11, 2005, 06:26:21 am »

what grit paper did you use to buff the glaze off -

back in the 70's rebuilding old big blocks - we used 400 emery and just went with that.

Does this jive with your rebuild?

Thanks - C

Rat407 · « **Reply #9 on:** August 11, 2005, 08:55:18 am »

Quote from: "ejust"

ive got a brake cylinder hone..would that work ?? How long does a quickie rebuild usually last?

And what can i do about my oil pressure being at 10psi at idle warmed up?

Sounds like the intermediat shaft bearings. Those are the first to go. The mains and rods last a lot longer. Mine mains and rods were well within factor specs with 156k on them. The intermediate shaft bearings were worn.

ejust · « **Reply #10 on:** August 12, 2005, 02:58:05 am »

if the intermediate is shot, how do i replace those..can it be done with engine in car? And how....

Rat407 · « **Reply #11 on:** August 12, 2005, 04:01:06 am »

I have not done them in the car. But was told that you can by removing the back engine mount and the front engine mount, this is on a 91 jetta, not sure of other models, maybe someone else can jump in, anyway once the mounts are off then you can lower the engine enough to be able to get the intermediate shaft out throught the right front wheel well. Of course you will have to pull the right front wheel as well to get into that are. Getting the bearings out takes a special tool, or if you do a search on here there are a few that made one out of an old intermediate shaft.

I don't have any oil pressure at my head when the engine is at operating temp. Don't know why because I just rebuilt the entire engine with all new bearings and checked all clearences and I'm well with in spec according to the Bentley. Just seems weird to have 20psi at startup and then drop to 0 once warmed up and stays there. So far I put 7k miles on the engine like that and no problems at all. Runs strong and gets 46mpg.