I've come to the realization that I need to tear my engine down. It slowly leaks antifreeze into the crank case. I have pressure tested it to confirm it. The motor does not have much time on it. I bought it knowing this was a problem & that it had overheated (presumably from the lower hose sucking in). Anyway, when I first had gotten the car back I was told that it had weeped coolant between the block & head on the pass side. I took it apart and put new head gaskets in (old ones appeared to be fine). I was thinking then that it was possibly a leak at the intake. Well it's together and does the same thing (leaks oil into crank case). Is there a way to isolate the area that is the problem. I would hate to take it apart again only to find out that it was just a poor sealing intake. The rear coolant passage has some pitting. I have not noticed the leak at the head & block again. I had found out a little more on the rebuild that was done and was informed that the head bolts are probably original or at least from the late 80's when the engine was rebuilt the first time. I figured I'd pick up new ARP bolts along with head gaskets, but it is also looking like a trip the the machine shop. The heads have presumably been surfaced and or cut a few times. The engine was rebuilt in the 80's, then again in 2000. Then the heads were pulled again for oversized valves & mild port work. I am guessing or hoping that this is my problem instead of the block....or even better the intake which is a Performer RPM. When I pulled it apart, there were no signs of water in the combustion chambers. Plugs were brown. Can a leak down tester give me any idea or do I just tear it down and carefully inspect....then take my head in. Any tips would be appreciated. Thanks

 

Check the water pump backing plate for a pinhole or severe pitting.

 

could pull the oil pan,add dye to the coolant,pressurize the coolant system and use a ultra violet light to look for coolant running down into the base.

 

x2 on the water pump backing plate they get thin and the threads tend to strip easily. If it is leaking at the intake I'd think you'd lose vacuum also. hook a Vac gauge to see if the needle is jumping or steady to the intake. This may be a place to start before you have to take the intake off and physically look down inside. if the leaks just internal and the intake is sealed all this will be completely useless info. but like I said something easy to start with. will give you a quick yes or ehh maybe answer.

 

Thanks for the replies. I don't know how well the vacuum gauge will work. It has a comp XE284 cam in it, so I don't know how this may affect vacuum. I will pull the water pump off. Thanks!!!

 

The water pump backing plate had been replaced and is in good condition. I also pulled the intake off. It's hard to tell if the intake was leaking at the water jackets. I did have one gasket that appeared to be wet on the under side of the gasket, but the way things come apart with residual water it is hard to tell. I am going to try and isolate the rest of the engine and check it with air pressure (unless there is any reason someone says that I shouldn't). I am not planning on using much pressure, but the test would be similar to how a plumber pressure tests a system. I have covered the water ports with rtv & steel plates. I will reinstall my water pump and attach a tee with a gauge & valve. I would imagine about 15lbs pressure should work. I am trying to do a process of elimination. The heads have been machined more than once as far as I know and I am wondering if I have a poor mating surface??I also found a few head bolts that had loosened up from the 80ft-lbs they should have been.

 

(leaks oil into crank case)
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That's generally not considered a problem...



The heads have been machined more than once as far as I know and I am wondering if I have a poor mating surface??I also found a few head bolts that had loosened up from the 80ft-lbs they should have been.
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Hmmm.... 3rd generation machined heads, who knows how many cuts on the intake, and LOOSE HEAD BOLTS? I'm gonna go out on a limb here and guess that loose head bolts might lead to a head gasket leak. Maybe they need to be retorqued after a few heat cycles, whether the instructions say to or not.

Wonder what sealing regimen you used on the intake- I deviated from my known proper method once on the latest 403, and had to re-do it. With AL intake:
CHECK FIT DRY. Angles match? Intake hits heads before it hits block rails, etc. Bolts actually line up and enter the holes properly?
Fat composite gaskets. Aviation 3H permatex on all but the water ports. Right Stuff or similar RTV super THIN layer [no squeezeout] on water areas.
proper thick bead of RTV across the F&R rails.
Torque in 3-4 stages using the proper inward spiral pattern.
Go over them again and again at 35 until none turn more before clicking the wrench.

 

Sorry, water into crank case. I had a few loose bolts that started to turn around @ roughly 60 ft-lbs. I will take a closer look at the intake. The bolts do fit into heads just fine. So, I should seal every port? What's the difference between the rtv's that I should use two different types? I don't know where I could pick up AV rtv unless I special order it. I used a liberal amount of rtv at the coolant passages when I had it apart last time. I used Mr.Gasket's on the intake....figuring they were a little fatter to maybe soak up a difference with machining.