318 dodge still burning oil after hughes engines fix

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stang1999

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around 6 months ago I repaired my factory manifold gasket with Hughes engines kit because I believed it was the culprit. I installed it and everything seemed fine after a while.

yesterday I was at a stoplight and I noticed my truck was dying so I kept the RPMs up and drove into a parking lot where I found I was one quart low on oil. I filled it back up with some oil I keep in the truck and made it home.

Today I ran a compression test on my cylinders. The highest was 170 and the lowest was 150, I was happy with that.

so I essentially have oil being burned off at around one quart every 1k miles. I don't believe that the oil is being leaked out. I took a look down into the throttle body today and saw oil on the bottom of the intake manifold.

my guess is that the intake plenum is at fault again. but I'm not sure where I would go from here. what does everyone here think the culprit is?

the truck is a 1997 dodge Dakota 5.2 5 speed 4x4 with 250xxx miles.
 

Fast69Mopar

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around 6 months ago I repaired my factory manifold gasket with Hughes engines kit because I believed it was the culprit. I installed it and everything seemed fine after a while.

yesterday I was at a stoplight and I noticed my truck was dying so I kept the RPMs up and drove into a parking lot where I found I was one quart low on oil. I filled it back up with some oil I keep in the truck and made it home.

Today I ran a compression test on my cylinders. The highest was 170 and the lowest was 150, I was happy with that.

so I essentially have oil being burned off at around one quart every 1k miles. I don't believe that the oil is being leaked out. I took a look down into the throttle body today and saw oil on the bottom of the intake manifold.

my guess is that the intake plenum is at fault again. but I'm not sure where I would go from here. what does everyone here think the culprit is?

the truck is a 1997 dodge Dakota 5.2 5 speed 4x4 with 250xxx miles.
There will always be some residual oil in the bottom of the intake manifold. Do you have excessive oil?

To verify that the plenum gasket is leaking, remove the breather hose from the air intake and place your thumb over the hose. Does it pull a vacuum really quick or is it slowly pulling a vacuum?

If a vacuum occurs quickly against your thumb then the plenum gasket is leaking or cracked.

Did you use the metal shim gasket for the plenum or the paper-like gasket?
 
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stang1999

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There will always be some residual oil in the bottom of the intake manifold. Do you have excessive oil?

To verify that the plenum gasket is leaking, remove the breather hose from the air intake and place your thumb over the hose. Does it pull a vacuum really quick or is it slowly pulling a vacuum?

If a vacuum occurs quickly against your thumb then the plenum gasket is leaking or cracked.

Did you use the metal shim gasket for the plenum or the paper-like gasket?

the oil seemed to be pretty decently coated everywhere when I looked into the throttle body.

when I pulled the vacuum line off the airbox and put my thumb on it, I didn't really feel a strong vacuum. it pulled very slightly on my thumb.

let's say that the plenum was leaking again. Since I already spent money on this Hughes fix, would I just be able to weld the two aluminum pieces together to make a one-piece intake? this dakota is my daily so I just want to cut down on the oil consumption.

but since I didn't feel much of a vacuum, I'm not sure what the problem is here.

and I used I believe the paper gasket that came in the kit. the part number is: HUG 7720R
the link is: http://www.hughesengines.com/Index/products.php?partid=27091
 
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stang1999

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There will always be some residual oil in the bottom of the intake manifold. Do you have excessive oil?

To verify that the plenum gasket is leaking, remove the breather hose from the air intake and place your thumb over the hose. Does it pull a vacuum really quick or is it slowly pulling a vacuum?

If a vacuum occurs quickly against your thumb then the plenum gasket is leaking or cracked.

Did you use the metal shim gasket for the plenum or the paper-like gasket?

the oil seemed to be pretty well coated everywhere when I looked into the throttle body.

when I put my thumb on the hose on the air filter it pulled

let's say that the plenum was leaking again. Since I already spent money on this Hughes fix, would I just be able to weld the two aluminum pieces together to make a one-piece intake? this dakota is my daily so I just want to cut down on the oil consumption.

and I used I believe the paper gasket that came in the kit. the part number is: HUG 7720R
the link is: http://www.hughesengines.com/Index/products.php?partid=27091
 

pacofortacos

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Can't rule out valve seals either though at that age and mileage.
 
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stang1999

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Can't rule out valve seals either though at that age and mileage.

agreed, i’m not saying they aren’t, but since i was seeing oil in the intake manifold couldn’t that rule out valve seals from oil getting in there?
 

pacofortacos

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Is the PCV valve new or old? OEM or aftermarket? Could be a PCV valve too as it goes into the intake manifold.

Pull the PCV valve out of the valve cover (just leave it connected on the hose but out of the valve cover), block that hole in the valve cover and then hold your thumb over the breather hose on the other valve cover - if you get ANY suction, your manifold is leaking.
 
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stang1999

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Is the PCV valve new or old? OEM or aftermarket? Could be a PCV valve too as it goes into the intake manifold.

Pull the PCV valve out of the valve cover (just leave it connected on the hose but out of the valve cover), block that hole in the valve cover, and then hold your thumb over the breather hose on the other valve cover - if you get ANY suction, your manifold is leaking.

It's an OEM PCV valve, as far as I know, I bought the truck as a simple beater about a year ago.

I ran the test with the PCV valve plugged both on the hose and the valve cover. there was absolutely zero vacuum from the breather hose that's attached to the airbox. It actually had very little positive pressure which I believe is what is meant to happen.

now I don't know how I'm losing so much oil. I suppose the oil I saw in the intake manifold was just normal oil through the breather hose/PCV valve. so maybe my oil is leaking out, or through the valve seals. thoughts?
 

pacofortacos

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You should see a slight positive pressure with no PCV and no open hoses - normal blow by.

Do you see any puffs of smoke on a startup after sitting for a while?

External leak should be easy to see - it flows down towards the ground haha :)

Valve seals mixed with loose valve guides can use a surprisingly good amount of oil.

Sometimes a different weight or even brand of oil can stop usage - try a different brand and their High Mileage version of the oil 5w-30.

Adding a tablespoon or so of brake fluid to the oil can soften and swell the seals and help. Same basic thing that oil additives and high mileage oils tend to do.
 
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stang1999

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You should see a slight positive pressure with no PCV and no open hoses - normal blow by.

Do you see any puffs of smoke on a startup after sitting for a while?

External leak should be easy to see - it flows down towards the ground haha :)

Valve seals mixed with loose valve guides can use a surprisingly good amount of oil.

Sometimes a different weight or even brand of oil can stop usage - try a different brand and their High Mileage version of the oil 5w-30.

Adding a tablespoon or so of brake fluid to the oil can soften and swell the seals and help. Same basic thing that oil additives and high mileage oils tend to do.

I've never noticed any smokey startups, but ill keep an eye out for them, or any leaks, I have skid plates so ill have to crawl under to check.

what weight oil should I try? I use either 10w-30 or 10w-40 I can't remember off the type of my head. whatever the first google result was lol.

ill just keep filling it with oil every so often I guess. if it is valve seals id rather not deal with that haha

thanks for the responses everyone
 
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crazykid1994

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Mine I did the Hughes gasket. I wasn’t burning 1qt per 1000 miles after but it was a minor amount. Maybe 1qt per 5000 miles. Mine was valve seals. I did put a new pcv valve when I did my Hughes plate though. You should be able to tell if it’s the plenum gasket because you would see areas on the plate where it is more collected around the edges or see gasket pushed in. I did use the upgraded felpro gasket on mine too. My rear main leaked a tiny bit as well. Had 165,000 miles on it and still ram amazing. Not sure how it’s doing now though. The guy that bought it off us used it as a beater hunting truck then converted it to a swamp truck with 36” boggers and 4.56 gears and took it out to okeechobee mudfest a few times before I saw it up for sale on Facebook with huge dents
 
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stang1999

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Mine I did the Hughes gasket. I wasn’t burning 1qt per 1000 miles after but it was a minor amount. Maybe 1qt per 5000 miles. Mine was valve seals. I did put a new pcv valve when I did my Hughes plate though. You should be able to tell if it’s the plenum gasket because you would see areas on the plate where it is more collected around the edges or see gasket pushed in. I did use the upgraded felpro gasket on mine too. My rear main leaked a tiny bit as well. Had 165,000 miles on it and still ram amazing. Not sure how it’s doing now though. The guy that bought it off us used it as a beater hunting truck then converted it to a swamp truck with 36” boggers and 4.56 gears and took it out to okeechobee mudfest a few times before I saw it up for sale on Facebook with huge dents

wow that truck has had quite a run lol. I've narrowed it down to either valce seals or a leak somewhere. the diagnostic test I ran with plugging the pcv valve and testing the breather hose from the airbox for vacuum ruled out the plenum gasket being at fault.

i want to get this fixed asap because I always forget to check my oil level and by the time I've realized I'm low on oil the engine is bogging from lack of oil/ and or my oil pressure drops.
 

pacofortacos

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I never ran any heavier than 5w-30 on my 5.9.

Try the brake fluid trick or Restore additive and/or High Mileage oil vs. standard oil.
I had good luck with Havoline.
 
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stang1999

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I never ran any heavier than 5w-30 on my 5.9.

Try the brake fluid trick or Restore additive and/or High Mileage oil vs. standard oil.
I had good luck with Havoline.

sounds good, thanks for the advice
 

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Sometimes, the OEM bolts are way to short and dont pull the plate enough to seal or come loose. Or, to long and bottom out. Welding the plate will work. But the intake is oil saturated and requires lots of cleaning to run a bead. Check the IAC, hvac, cruise control hoses. The plastic hoses get brittle. Retorque the intake,VB. Someone mentioned the brake check valve and PC. All that oil will will ruin the o2 sensors, clog the Cat and leave massive oil deposits on the exhaust valves.
A new EFI intake is best, but Hughes has them on back order. Or an M1 somewhere out there. A last try is a simple one. The plate is good. The gaskets are to thick and rubber slides. I had good results by getting cork gaskets and permatex, indianhead gasket seal. The thinner the cork the better. Lastly, talk with John at Southeastern performance. John is the best and will help. Others sell parts.
 
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