1984 mecruiser 470

[jabfd]

Hi guys ive been dealing with A/f in my oil for a while which i switched to sraight water instead of a/f changing oil alot !!! checked weep hole a few times a ran paper clip thru and never and water /a/f came out . it has a new riser
my next step is headgasket any tips would be great thanks.

 

[stonyloam]

Re: 1984 mecruiser 470

If it is the head gasket, replace with a OEM Mercruiser HG. Try to get the antifreeze back into the cooling system fairly soon, so the cam under the seals does not rust.

 

[jabfd]

Re: 1984 mecruiser 470

will do i plan to start taking it apart tonight after work ill keep updating the post. i will use oem headgasket .also read that it could be a bad exhaust manifold so iam going to pressure test that after i take it off . i want to make sure its the head gasket before i go any further thanks

 

[Bondo]

Re: 1984 mecruiser 470

will do i plan to start taking it apart tonight after work ill keep updating the post. i will use oem headgasket .also read that it could be a bad exhaust manifold so iam going to pressure test that after i take it off . i want to make sure its the head gasket before i go any further thanks

Ayuh,.... Before ya year it down, drain it, 'n pressure test it with Air,...

You'll hear the leak, follow the sound,....

"n though I ain't sure, I believe that pump is capable of leakin' Inward(into the oil), yet not outward(through the weep hole),...

 

[stonyloam]

Re: 1984 mecruiser 470

"n though I ain't sure, I believe that pump is capable of leakin' Inward(into the oil), yet not outward(through the weep hole),...

Right, the weep hole is between the two seals in the timing chain cover, so any antifreeze that leaks (under pressure) past the first seal will leak (under no pressure) out of the weep hole rather than past the second seal into the crankcase. So if the weep hole is clear, and it is not leaking that is not your problem.

 

[jabfd]

Re: 1984 mecruiser 470

Right, the weep hole is between the two seals in the timing chain cover, so any antifreeze that leaks (under pressure) past the first seal will leak (under no pressure) out of the weep hole rather than past the second seal into the crankcase. So if the weep hole is clear, and it is not leaking that is not your problem.

thank you for your response when i ran a paper clip into the weep hole about 2 to 3 inches does that sound about right to you ?

 

[jabfd]

Re: 1984 mecruiser 470

Ok update I pressure test the a/f. System with the system full it would not build pressure for long and I can hear it leaking I took the riser off and the exhaust manifold was full of a/f. Pulled out the plugs number 3full of a/f when I pulled the plug the a/f started coming out of the cylinder and the level dropped down in the exhaust manifold so how can I test the exhuast manifold

 

[Bt Doctur]

Re: 1984 mecruiser 470

remove the manifold, make a jig to stand it upright, use a hose to fill the manifold up to the riser ports and see if it runs out the manifold ports, Yes ,the manifold is cracked. If there is no leakage, pull the head and inspect for cracks. Head is a Ford 460 head.

 

[stonyloam]

Re: 1984 mecruiser 470

thank you for your response when i ran a paper clip into the weep hole about 2 to 3 inches does that sound about right to you ?

Yes, sounds like it is clear.

 

[jabfd]

Re: 1984 mecruiser 470

remove the manifold, make a jig to stand it upright, use a hose to fill the manifold up to the riser ports and see if it runs out the manifold ports, Yes ,the manifold is cracked. If there is no leakage, pull the head and inspect for cracks. Head is a Ford 460 head.

bt i would have to cap all the hose ports right and fill it up and then i can pressure it up right if water comes out and i lose pressure then its a bad manifold if anybody has a better way to test please let me know thanks

 

[Bondo]

Re: 1984 mecruiser 470

bt i would have to cap all the hose ports right and fill it up and then i can pressure it up right if water comes out and i lose pressure then its a bad manifold if anybody has a better way to test please let me know thanks

Ayuh,.... No water involved, Drain it dry 1st, so ya can Hear the leak,....

Air only,...

 

[jabfd]

Re: 1984 mecruiser 470

bondo iam using a A/f pressure tester from auto zone will that work if there is no water in the system thanks again for everybodys help

 

[stonyloam]

Re: 1984 mecruiser 470

bondo iam using a A/f pressure tester from auto zone will that work if there is no water in the system thanks again for everybodys help

That is a little different. You use it with the system full. Two ways: One where you pump air in to see if it holds pressure, and secondly with the engine running to see if there is an increase in pressure from a head gasket leak. 470's are a different animal. Used that on mine, works pretty well.

 

[jabfd]

Re: 1984 mecruiser 470

That is a little different. You use it with the system full. Two ways: One where you pump air in to see if it holds pressure, and secondly with the engine running to see if there is an increase in pressure from a head gasket leak. 470's are a different animal. Used that on mine, works pretty well.

Hi guys
I removed exhaust manifold pressure test it and I can hear a leak up by the riser. But I can't see where it's coming from. Now the riser is new. And gasket is new the problem iam having is that before I put the riser back on the manifold it was full so how can the manifold not loose and a/f overnight but when. I put a little bit of pressure it leaks right out and in to the exhaust section help anybody

 

[jabfd]

Re: 1984 mecruiser 470

Any one please aim stumped don't want to spend the Money on manifold if I don't need one thanks in advance

 

[stonyloam]

Re: 1984 mecruiser 470

Not quite sure here, but a bad gasket between the reservoir and exhaust manifold, even though it is new. You might want to try an OEM gasket.

 

[jabfd]

Re: 1984 mecruiser 470

Not quite sure here, but a bad gasket between the reservoir and exhaust manifold, even though it is new. You might want to try an OEM gasket.

I picked up an oem gasket but i have another Sierra one that is brand new so I clean the old gasket and put the new Sierra on first thinking is was because the old gasket had failed but when I put the new Sierra gasket in nothing changed not even a little bit can't build up pressure . So I took riser off and the inside is pretty Scaley the surface I clean and the gasket sit perfect so I would think it should hold a little better I have the oem but at 44 bucks a wack I want to be sure if any body know a better way to test the manifold please let me know I think iam going to need a new / used manifold at this point

 

[Live-liner]

Re: 1984 mecruiser 470

Post a picture of the "manifolds" machined surface that the riser sits on. I believe it is not in good enough health to hold a gasket. You may have to have it machined down a bit or replace. I had the same issue, once machined, problem was solved.

 

[jabfd]

Re: 1984 mecruiser 470

Ok. Well I clean up the surface on my manifold its not to bad for cast ion
and then pressure tested the system with the Sierra gasket still would not build pressure .
I sanded the surface some more still nothing I put rtv red up 650 degrees and pressure started to hold still dropped a little bit but that could be my connection and caps off
Now with the new mercruiser gasket should I. Put any rtv or other sealant please let me know. If any ever used a sealant and if it worked out good thank you liveliner you on the money with that surface of the riser. Also how much did you pay to resurface yours if I go that route

 

[jabfd]

Re: 1984 mecruiser 470

Ok. Well I clean up the surface on my manifold its not to bad for cast ion
and then pressure tested the system with the Sierra gasket still would not build pressure .
I sanded the surface some more still nothing I put rtv red up 650 degrees and pressure started to hold still dropped a little bit but that could be my connection and caps off
Now with the new mercruiser gasket should I. Put any rtv or other sealant please let me know. If any ever used a sealant and if it worked out good thank you liveliner you on the money with that surface of the riser. Also how much did you pay to resurface yours if I go that route

update
i put the oem gasket on and leaked air right out . live liner can you tell me where you had yours planed down and how much thank you .