possible magnum intake leak?

[schwinger]

I have a 1998 5.2 magnum engine in my 72 dart with mild cam 490/490 lift 108 lobe separation, cant remember duration, speedmaster 4bbl intake and fitech, stock exhaust manifolds, stock rebuilt magnum heads that have been milled .010, blocks been milled but dont know how much was taken off and has flat top pistons. Driven the car for awhile with about 12000 miles on the motor and recently started smelling burning oil when i get on it so checked all spark plugs and found out #2 cylinder was fouled up with oil. looking into the cylinder with a flashlight it looked pretty oiled up so wondered if oil ring got messed up or piston cracked idk so Did a compression test and all cylinders were 150 except that one which was 180, higher than the others so wondering whats going on? Did take the valve cover off and checked the valve seals on that cylinder which looked to be pretty good and wasnt loose but did notice bottom of valve cover had a thick brown almost milkshake film to where i wonder now if the intake gasket is leaking or not.

 

[schwinger]

Hears a pic of the valve cover. Did Check the dipstick and it wasn’t that color brown tho but Normal oil.

 

[Willyrd]

That looks like coolant is leaking in there. Never hurts to slap some new gaskets on there

 

[Lelo Dart]

Are you using a PCV? That sounds like that could be it.

 

[Garrett Ellison]

It may be time to do this. I use pieces of old tire weight I draw out and flat in a vice instead of the jewelry wax but you can also hole punch the old gaskets and use lead shot, but keeping up with four individual pieces of shot when the intake comes back off is more problematic.
http://www.hughesengines.com/Upload/TechArticles/INTAKE_MANIFOLD_SEALINGJULY2015.pdf
Bear in mind that it may also be the front cover or the the crack prone magnum heads, though. I would drain and air pressure test the cooling system and listen with a pipe or mechanics stethoscope first to see. The real headache is cleaning everything out after a coolant leak into the oil. If under the manifold is full of the same gunk then sludge is in everything and needs to cleaned out of the lifters by taking them apart and washing them out in solvent. It's best to pull the engine and take it down to a long block to clean it out. It can be done in car but it's best to pull the pan and clean out the crankcase too, so it's usually easier out of the car, IMHO.

 

[jos51700]

Leakdown test will help you diagnose, but I'd look at the cam and valve system on that cylinder. If you're losing lift somewhere, that can drive up cranking compression numbers.

 

[schwinger]

Are you using a PCV? That sounds like that could be it.

Yes I’m using a pcv however just noticed the hose was cracked where it connects to the throttle body.

 

[schwinger]

Will try to do a leak down test on it hopefully later on today. Also did drail the oil since it’s due for an oil change anyways and didn’t notice any sludge coming out.

 

[Garrett Ellison]

What does the plug look like in the odd cylinder and the ones closest to it? Any of them look like they been getting steam cleaned? How much mayonnaise is on top of the head?

 

[schwinger]

No mayonnaise on top of the head.

Plugs next to the oily plug look nice and brown with the exception of number 5 but doesn’t look green and has a slight brown which is hard to see in the pic.

 

[Garrett Ellison]

That’s really good, I’m glad to see that it’s probably just humidity and condensation. The cracked pvc hose is probably the cause of the under valve cover crud. Still, as noted, not a bad idea to double check the intake manifold. What are you running your coolant temperature at? I do agree with leak down test to diagnose things further. I haven't had any experience with the Speedmaster intakes but the general consensus I have read on here is they are mostly trouble free.

 

[schwinger]

I think it is too but Got to do the cylinder leak down test only on one side so far with the one that has the oily plug and That bank of cylinders were 4 to 5% leakage except the oily one at 3% which since it’s oiled up I figure it would leak less but will get to the other bank hear in a bit. I have a 190 thermostat in it now and it’s been in the 100s hear and hottest it gets at a long idle in traffic is 210.

 

[motorpirate]

I think it is too but Got to do the cylinder leak down test only on one side so far with the one that has the oily plug and That bank of cylinders were 4 to 5% leakage except the oily one at 3% which since it’s oiled up I figure it would leak less but will get to the other bank hear in a bit. I have a 190 thermostat in it now and it’s been in the 100s hear and hottest it gets at a long idle in traffic is 210.

I have that same intake and when using the LA bolt holes found a severe port mismatch..
You may want to pull the intake.

 

[schwinger]

Ok did the other bank and all are at 4 to 5% leakage so I think I’m good there. Took the intake off and found an oil stained area where it seemed oil was getting in the port that goes to the cylinder that has the oily plug as well as a small streak in the intake also so I think it’s definitely the intake leaking.

 

[schwinger]

Also on the intake gaskets, the drivers side looks like it has a good inprint on it but the passenger side the lower part of the gasket it seems like it wasn’t sealing right especially where the intake port was where the oily plug was at so I’m pretty sure the intake gasket failed.

 

[schwinger]

There wasn’t any sludge under the intake either so that was good. Cleaned up the surfaces and put the intake on dry with no gaskets and noticed it was sitting higher on the passenger side. took it off and found the little tab that holds the intake gasket up was getting in the way of it sitting flat and also noticed that little tab left an inprint on the intake gasket also so I think I found my problem. Did check the angles on the head in relation to the intake and the intake was a couple degrees off, used an angle finder for that so I think that’s good. Gonna check later on on doing that washer thing but got new gaskets ordered and might change timing cover gasket also while I’m at it