Getting #5 exhaust Valve to seal without pulling head

Dodge Ram 1500 4wd with 5.9 gas engine 1999 year model


Compression check showed a Miss and a leak on #5 cylinder with air coming out around exhaust valve and the tailpipe at 150psiof air.

Truck was running fine and uses no oil,miss at idling and drop from 17 mpg to 10 mpg.recently.still uses no oil.Also gas smell at exhaust when running.

Any way to get the Valve to seal without pulling head?

Thanks
Craig

In a word, no. Even if it's a spring you'll need to pull the head. If it's burnt, you'll need to pull the head. If it's bent, you'll need to pull the head.


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As stated by sbarron, you cannot do anything to the valves except rotate them without pulling the head.

Well, in practice, i've replaced two valve springs without removing the head, but it's a pain like no other, I would never do that again.

Should you decide to remove the head, get ready to replace them as more likely than not, they are cracked. Since that valve is leaking, I bet that is where its cracked.

dudeman2009 said:

As stated by sbarron, you cannot do anything to the valves except rotate them without pulling the head.



Well, in practice, i've replaced two valve springs without removing the head, but it's a pain like no other, I would never do that again.



Should you decide to remove the head, get ready to replace them as more likely than not, they are cracked. Since that valve is leaking, I bet that is where its cracked.

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Yes. Should have stated that. Learn from our mistakes. I TRIED to replace a spring without taking off the head. Ended up taking off the head.

As dudeman said, if you pull one, pull the other and plan on at least having them rebuilt if not putting some remans on. Plan on new lifters, pushrods, etc. wouldn't be a bad time to change the cam/bearings either as long as you're there. Also, don't forget your new timing set.

Unfortunately, unless you are trying to go REALLY cheap, you should rebuild the top end. When you've already sprung for new/reman heads plus the labor to R&R them, the rest is peanuts and you're already there.



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A bit of seafoam or marvel mystery oil on the valve springs can leak down through the seals can help free em up and clean the top in SOME cases but no promises

It sounds like a burnt valve, or a piece of carbon managed to get between the seat and valve, which will require you to pull the head. you might be able to pull the spring and rotate the valve a couple times and see if that makes a difference.

I have had great success removing carbon deposits which drastically improved idle with. . . Water!!! My 92 Cherokee that was drinking oil for far too long due to bad valve stem seals, and a 97 Altima that was just a pos. sea-foam works good, but water works better, the added benefit is no smoke, and its cheaper if that matters. If using water be sure to use a misting garden sprayer so you don't hydro-lock your motor!!! The engine being at operating temperature is also critical to a successful cleaning. Sea-foam is safer if pouring, otherwise water in a misting sprayer works better.

There are a couple things you can do to replace a valve spring spring or valve stem seal without removing the head. I have done it both ways successfully.

Remove the rockers on whatever cylinder you are working on and.

Use a 20+ gallon compressor connected to the spark plug hole with a compression tester fittings, dump as much air into the cylinder as it will take. Take a socket with the same OD as the spring retainer and smack the spring a few times to loosen up the retainers and keys, I had to use a surprising amount of force and smacks to loosen up the retainers on my old Jeep. then use the proper tools to remove the spring, retainers, and keys.

The second way is drop the piston to the bottom of the stroke and shove about 5 feet of 3/8" nylon rope into the spark plug hole, then rotate the crank by hand to compress the rope against the valve. then remove the spring etc. . .