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2 lubricate or not 2 lubri..that is the question


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I will soon be reassebling my 96 2.35 DOHC...(blown head gaskets)

I sure hope it goes well ...LOL

 

I was wondering about the threads on the head bolts and cam shaft bolts and oil paan bolts--should the be lubricated with oil or anti-sieze compound...or should they be solvent cleaned and put in dry

 

What's the concensus on other threads such as intake bolts, water pump bolts. & oil pump bolts?

 

I read in another post a while ago about blue loctite?

What bolts should get this application?

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It SHOULD specify in the manual if anything is needed. Every gasoline engine I have worked on specified a coat of oil on the head bolts. On a Subaru engine, that's the only special procedure I use. All the other bolts get cleaned and put in dry. If you use anti-sieze, it will change the actual torque value, which may cause problems (I'm thinking specifically about your camshaft cap bolts here...too much torque could squeeze the cams too tightly and wear out the bearing surfaces).

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<<It SHOULD specify in the manual if anything is needed. Every gasoline engine I have worked on specified a coat of oil on the head bolts. On a Subaru engine, that's the only special procedure I use. All the other bolts get cleaned and put in dry. If you use anti-sieze, it will change the actual torque value, which may cause problems (I'm thinking specifically about your camshaft cap bolts here...too much torque could squeeze the cams too tightly and wear out the bearing surfaces).>>

 

+1

 

if you tourque the bolts correctly, no need for antisieze.

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i put a dab of oil on the threads, i thought that was fairly common and even mentioned in the FSM? maybe i'm wrong.

 

if any of the other bolts were difficult to remove (or sheared off) due to rust or corrosion i'll put antiseize or oil on those, but otherwise dry all the way around. the intake manifold bolts are notorious for rusting and seizing on the older subaru's. i've had at least 4 motors where the bolts sheared off trying to remove them and many are rusted/tough to get out. but i doubt you'll find any like that on yours.

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  • 2 weeks later...

Consider changing to studs instead of head bolts. Two reasons, as follows:

 

1. Studs torque more evenly, as the load is truly along the axis of the bolt; there are no rotational forces.

 

2. You can never-sieze where the steel stud hits the aluminum casing, so you will be able to take it apart again next time. Steel and Aluminum don't play well together over the long haul and tend to oxidize into a chalky white permanently bonded mess.

 

I've never rebuilt an engine using head bolts. For a few dollars more, use studs, nuts and hardened washers. Also, consider double height nuts, as the loading per thread is significantly lower.

 

FYI - This is general information. I've never rebuilt a Subie engine.

 

Jack

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Consider changing to studs instead of head bolts. ...

...For a few dollars more, use studs, nuts and hardened washers...

But just make sure that the replacement studs and nuts have the correct material and chemical specs.

 

I would want to buy replacement studs from Subaru, just to be sure.

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