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Hello Fellow 7th gen survivors!

4529 Views 2 Replies 2 Participants Last post by  Blues_hawk
Hi folks! I'm the proud owner of a 2004 Civic EX 4dr Automatic I use as a commuter car but also enjoy the occasional brisk romp around these twisty mountain roads around my house in Patrick Co.
(for a thrill try google streets on SR40 out of Woolwine, or SR8 down from Tuggles gap)

I recently suffered through the overheating/head gasket problem common in the D17a2 engine and joined to share my findings, and give back a bit after finding the posts so helpful along the way.

****I haven't used this type of forum very often so I thought I should ask: is it okay to add my thoughts to the old threads (on this issue) that I used during diagnosis? I have new information that might help and would like someone to test a theory when they start troubleshooting the same problem which I think would be worth trying before tearing the whole engine down.

I think it's actually exhaust gasses leaking into the coolant in the water passage/EGR assembly and not a head gasket.

No white smoke, mixing of fluids, loss of compression or fouled plugs which normally indicate a blown or leaking head gasket(HG) made me wait a very long time before taking on the task of replacing it, and only the presence of exhaust smells in he overflow finally caused my to buy a gasket set and start work. When I saw this arrangement while isolating the head for removal I thought it might be related, but was already well into the job so I continued the HG without trying it.

It makes more sense to me than a blown HG because the EGR gasses are post combustion chamber and not subject to intake vacuum so no water would be sucked in on the intake stroke. The gasses would also stink up the coolant. The water passage/EGR manifold uses a crush type gasket but the shop manual doesn't detail a torque cycle or spec, a level and flat check or any other special service of this component...which I didn't like during assembly and used a torque wrench cross pattern and took it to 28lbs per bolt specs. I'd like to see others test this as a standalone project/solution before tearing the head down. it could save us all a ton of time and cash.
In short: Just replace the Water passage/EGR manifold gasket to stop it from blowing water into the overflow...maybe.

I hope this helps someone in the future.

Wheels down!
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I am replacing this same water passage and metal gasket on my 2003 Civic LX. I am going with 16 to 19 ft-lbs of torque, based on the following.

This site suggests a certain Honda's water passage bolts are torqued to 33 ft-lbs, and water outlet bolts and nuts are torqued to 16 ft-lbs: . I do not know the difference between the two bolts. But 33 ft-lbs sounds way too high for a re-usable 8 mm diameter bolt.

The intake manifold is attached to the cylinder head with 8 mm nuts and bolts, torque spec 17 ft-lbs.
The exhaust manifold is attached to the cylinder head with 8 mm nuts and bolts, torque spec 23 ft-lbs.

These Porsche head gasket changeout instructions say 19 ft-lbs for any 8 mm bolts:
Cylinder Head and Head Gasket Installation

This generic guide says apply about 19 ft-lbs (dry) of torque for an 8 mm diameter bolt:

We're bolting into aluminum. I figure the water passage bolts see temperatures more like those at the intake manifold. The goal is to have it tight but taking great care not to strip the aluminum.
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Followup on this old thread, she's got about 90k on this repair now and still climbs mountains daily. I agree with the above lower torque specs, noting the aluminum threads are weaker than the bolts. Mine did not pull out at 33lbs but some could, best go with 18-20ftlbs to be safe, and be sure to buy a new crush gasket. I know at least one local shop that was scratching their head after trying to reuse the old one.
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