Head gasket and surface prep recommendation

rwmm415 · Post by **rwmm415** » 20 May 2017, 11:40

I'm just about to re-do the head gasket on my 5-cyl (98 v70 NA) again -- arghhh. I tackled this beast of a job 2 years ago and only got it about 90% right. The engine runs OK and doesn't smoke or overheat, but I can see evidence of exhaust getting into the oil and the coolant. The car been sitting mostly unused since then.

Now the nice weather has returned (in NorCal) and I'm going to take another shot at it and try to get it 100% right this time. My questions are mostly about gasket and surface preparation so I'll get a complete seal this time.

1. First of all, what kind of head gasket should I use on this engine, MLS or composite? Is their a particular brand/model you'd recommend?

2. Should I use a sealant on the gasket, like copper spray? I know that depends on the gasket, so these two questions go together. Also, I've seen conflicting opinions about using sealant even for gaskets that call for it, so I'd love to hear different points of view about this.

3. I'm going to get the head resurfaced again. Any recommendation for the surface finish (Ra)? I didn't pay any attention to this last time. I just thought shiny was good. This time I'd like to specify a finish when I take it in.

4. What - if anything - can I really do about block preparation? I cleaned the deck of any residual gasket material last time, but what else can I do? I have no intention of pulling the engine. I've heard some people talk about hand-lapping the deck. What tests can I do to decide if the block is out-of-spec and needs additional work?

This is a lot of questions, I know. If you've been through this yourself, please let me know what worked for you. If there's a posting that already goes over this set of issues for the Volvo 5-cylinder, please point me in that direction. Thanks.

Post by **rspi** » 21 May 2017, 17:13

I have an entire series of head gasket work. Not sure if they will help you or not.

Post by **tryingbe** » 22 May 2017, 09:59

Why did the headgasket needed to be replace in the first place? Overheated? If so, you need to get a strange edge and measure the block and head mating surface and make sure they are straight enough, or else you're going to have issues.

http://www.superstreetonline.com/how-to ... ion-check/

clifford06 · Post by **clifford06** » 23 May 2017, 18:47

Greetings. Sorry to hear. My head started to leak less than a year after my first DIY headgasket job. Mine leaked at the rear of head. Just a thought, check your head bolts for tightness before removal. See if the bolts will tighten up before you remove them. I know its been 2 years , but if they do seem to to tighten up, your problem may have been incorrect torque when you installed the first time. That was my problem. Anything you/me learn when we have to go back "in to" an engine only helps us on reassembly .

101 · Post by **101** » 24 May 2017, 06:19

On my V70 GLT head gasket job last year, I used the Volvo part and applied copper spray to both sides.

Mine was done for a burned valve, not an overheat condition.

15,000 miles later ... everything is great.

rwmm415 · Post by **rwmm415** » 26 May 2017, 13:16

Thanks, 101 and Clifford. This time I'm going use a stock EOM gasket and copper spray. I'm going to take the head to a shop with a better rep to get it checked and resurfaced. And, I'll pay more attention to the torquing process (the stages).

Thanks, Tryingbe for the note on checking the engine deck.

I'll report back when it's all over...

Post by **erikv11** » 26 May 2017, 20:32

OEM head gasket is a good idea, I went with that both times I have done it. My first head gasket job I ruined the engine block surface. I ditched the engine for a used one with a lot lower miles; engine swaps are much less technical than head swaps. A lot heavier, but a lot easier.

Post by **JimBee** » 27 May 2017, 05:47

erikv11 wrote: ↑26 May 2017, 20:32 My first head gasket job I ruined the engine block surface.

Erik, what did you do that ruined the block surface?

Post by **erikv11** » 27 May 2017, 08:56

I can't say for sure what went wrong because I never checked the block surface for flatness, but the end result of my first head gasket job was coolant leaking very slowly into the combustion chamber(s). When I opened it back up I could see evidence of where the coolant was leaking but I did not do any more extensive autopsy or corrective attempts, I just junked the block. I am pretty sure it leaked because as per some recommendations from seasoned posters (not from this site), I had used a flat block with sandpaper to remove some last bits of gasket material! There was a faint leak channel in one of those areas. I had been so careful and paranoid about the surface, but botched it anyway. So now I preach to never, ever use anything but a razor blade, and to be super meticulous with the surface. The next job went fine but I knew a lot more by then, too.