Vtec04

I put a D16Y8 intake manifold on my 2005 Civic VTEC 6 months ago. The intake manifold gasket never sealed, I tried 2 new gaskets for a D17 and 1 for a D16. Fail. Tried coating a gasket in RTV silicone to help it seal. Fail. Tried just RTV silicone with no gasket. Fail. After 1 month of trying to make this POS seal after installing it, I gave up for 5 months until now and I got fed up with the stumbling and rough idle, and I am ready to try to make this seal again. I am thinking the RTV silicone is not strong enough to withstand the vacuum. I think what I will try, let me know if you have a better idea, is coating the side of the metal gasket that touches the intake manifold with JB Weld, clamping the IM to a piece of flat glass with the gasket in place and letting it dry for 24 hours. Once the JB Weld is dry, I would trim excess JB Weld from around intake runners, bolt holes and ports. I would then reinstall the IM with the gasket epoxied to it but the side that touches the head dry. That way I can easily remove the IM for repairs and such but no more leak. At least in theory. If I need to remove the gasket, I would heat it with a torch and rip it off with pliers since it is metal, and simply sand off the remaining epoxy. Would this work? Thanks.

TomCat39

First thing that comes to mind. How do you know it's the IM that is not sealing?

Lets say you are correct, instead of crappy RTV you might try Loctite 30558 aka 5109:

LOCTITE® NS 5109? High Temperature Gasket Sealant - Henkel

LOCTITE NS 5109 High Temperature Gasket Sealant

(Known as Loctite High Temperature Gasket Maker )


LOCTITE® NS 5109™ High Temperature Gasket Sealant is a slow-setting, non-hardening, high-temperature sealant. Recommended for heavy-duty applications. Seals up to 5,000 psi. Temperature range is -50°F to 600°F (-45°C to 315°C) intermittent. Resists common shop fluids. Applications include aircraft heating systems, steam lines.



I'm not sure if the IM gasket is exposed to gasoline. That might be the only challenge as 30558 resist most fluids but I think it is susceptible to gasoline.

Use alcohol to clean up before it cures.

Vtec04

Thank you for the product suggestion, and I know it leaks because if I spray water around the flange the engine stumbles and stalls, along with the hissing noise.

motoxxxman

maybe the flange is damaged or warped. you could always bring the manifold to a machine shop to get shaved bare minimum for straightness. in the very least, have them check it for straightness

holmesnmanny

You want to put rtv but don't put them completely together. You want a small distance of rtv in the middle. Let it cure for 4 hours or more. Then tighten it down. My guess is you're trying to drive it before it has a chance to cure.

Vtec04

I already had it checked. It is flat.

TomCat39

Are you using an OEM paper gasket?

The red paper (cardboard) gasket from Honda is by far the best IM gasket. Felpro's gasket sucks.

Vtec04

AFAIK the OEM D17 gasket is metal.

TomCat39

For the intake manifold? That seems a little odd to me. I assumed Honda stuck with the same red paper gaskets as they used on the D15's and D16's.

I know the exhaust is a non coated mls type gasket, didn't think they would go that route on the intake though.

Will have to check with my buddy, he's got the 7th gen civic 1.7L that he plans on supercharging.

Vtec04

Yep, it is a single layer steel gasket. TO me it seems like using metal to seal metal to metal won't work too well. Will running it with the vacuum leak actually harm the engine? Thanks for the help to everyone who replied.d

TomCat39

It throws just about every sensor off to some degree. It causes the ECU to be on perpetual relearn status and keeps the car from running anywhere near optimally.

I think for your purpose I would either use the loctite on the gasket or get yourself some Permatex "The Right Stuff" grey (Hondabond flange sealant) and put a coating of that on both sides of the gasket and install. The right stuff, you only have 5 minutes to get the IM on and torqued to spec.

BrakeExpert

Big red flag:

did you say a d16y8 manifold on a 2005 civic?
The 01-05 Civic uses a D17 engine. This engine isn't as similar to the 88-00 Civic D-series as you might think. The D16y8 (which is from a 96-00 Civic EX model only) is used as an upgrade common to 5th and 6th gen civics. Also, there are varients for that manifold. The automatic 96-00 d16y8 manifold has the IACV in the throttle body while the manual transmission model has two holes on the back of the plenum for a separate IACV that bolts to it. so theres more than one d16y8 intake manifold. Also. I forget if this applies, but in 99-00 Some Civics had "air injection" and the intake manifold had holes for it. So You need to know if the manifold was from an automatic or manual, and also what year it was from. I do recall the d17 also having an EGR valve. the 96-00 Civic HX had an EGR system, but all other 88-00 Civics did NOT use an EGR, including the D16y8. So, it might not be sealing cause its the wrong part and simply wont fit. You might wanna google pictures of the two.

Vtec04

Thank you very much. Will The Right Stuff be likely to seal any better than the RTV silicone? thanks

TomCat39

Please see this gentleman's post. It's highly informative.

Strong evidence it may not be the gasket!

Quoted below for good measure.