valve cover leak

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XtechX

XtechX

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Edmore, Michigan
I have a 340 and am running the mopar performance cast aluminum valve covers. You guessed it....it's leaking on the passenger side near the back of the cover.
I have tried 3 different gaskets on it and have ground the cover where it hits on the intake and it still leaks. I tried tightening them right down, not tightening them too much and still its failing to seal. I just bought some rubber gaskets, but they're not very thick and some ultra black rtv sealant. Should I use just the sealant and nothing else or a combination of the rubber gasket and the sealant ? Im at my wits end with this leak! If anyone has any sure fire leak solutions, Im open to any suggestions????
Also, why do they only leak on the passenger side and not the drivers side? It seems, if you have to grind for the intake runners on the right, why not on the left...just curious? Thanks for any help you can give, Roy.
 
I ground an area on the VC at an angle so it cleared the intake. I used a die grinder and a sanding disc and went slowly but surely. If you look at my MP valve covers, you can't see the area I ground unless you are leaning in and know where to look. I can take some close ups, but it is a little hard to see. Let me know if you want pics. I had perpetual VC leaks until I did this, and I haven't had a drop leak since I did this in April.
 
My 383 leaks like that on both sides, for the 21 years I have owned it. I have tried both stamped steel and cast aluminum valve covers, different gaskets, expanding foam gasket stuff, straight RTV. It always seeps a bit, and drips on the starter and exhaust pipe. I see 2 problems - 1) oil pools there, at or above the level of the gasket and 2) the surface on the heads is not flat, falling away ~1/8" at the rear of both heads.

For #1, I knocked off the casting flash that was keeping the oil from draining back, maybe helped.

For #2, I tried first snugging down the rear bolt on the cast alum VC, then pulling down the rest. That was with a fairly stiff red silicone gasket. The ear on the Holley VC broke off, ruining it, but proving the surface wasn't flat.

If I ever pull the heads again, I will get a shop to mill a flat surface, and grind down the flash. Or, if I can find affordable alum heads, I will try that and take some weight off the front end too.
 
Not sure why it only hits and leaks on the right side but as mentioned grind until you have plenty of clearance. I had the same covers on my 360 and had to grind both sides the same and even then had problems getting it to seal until I bought some extra thick cork gaskets at Autozone (weren't on stock, had to special order them). The name brand was ROL and if I remember right they were 3/16" thick. What worked good for me was using RTV on just the valve cover side effectively glueing the gasket to the valve cover. Didn't use anything on the side that contacted the heads. Put them on and torqued them down then the next 3 or 4 times I ran it and let it cool down I re-torqued them. Never had a leak again and since I only glued them on 1 side I was able to take the covers off and re-install them after adjusting the valves. Probably had them on and off 5 or 6 times and they still sealed good every time.

Oh ya, make absolutely sure there isn't any oil at all on what your applying RTV to or it won't seal.
 
I think it’s just an inherent problem with Mopar only using 5 bolts to fasten down the covers. It takes extra attention to making sure you get equal clamping force on all bolts when only using 5

I have done the typical grinding of the covers to clear the intake runners. I use the reusable rubber gaskets with the metal spacers to prevent over tightening. They go on dry and with extra detail to torque sequence I have never had a problem. On the other hand my problem is the sealing of the front valley of the intake. Already had it milled once and may be doing it again to get it to seal.

Good Luck
 
71swing said:
I think it’s just an inherent problem with Mopar only using 5 bolts to fasten down the covers. It takes extra attention to making sure you get equal clamping force on all bolts when only using 5

I have done the typical grinding of the covers to clear the intake runners. I use the reusable rubber gaskets with the metal spacers to prevent over tightening. They go on dry and with extra detail to torque sequence I have never had a problem. On the other hand my problem is the sealing of the front valley of the intake. Already had it milled once and may be doing it again to get it to seal.

Good Luck
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I'm sure the 5 bolts has some to do with it, that's why on the magnum engines they went to 10 bolts. Throw away the factory end gaskets and use just RTV there. Been doing it that way for yrs. and never had a leak yet.
 
fishy68 said:
Throw away the factory end gaskets and use just RTV there. Been doing it that way for yrs. and never had a leak yet.
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Yeah, I've never have used the ends. Was taught from the beginning to only use RTV. I have an airgap and it has always had a good sized gap in the front valley. I have never been able to get it to seal correctly. May be in the market for a M1 this time around.
 
Same problem here , do they make those valve cover washers that apply pressure along the lip ? I use the chromed steel covers and cannot get them to seal . Just ordered 4 different types of gaskets , hope one of them works . Fel-pro rubber/fibre , SCE composite steel core .125 thick and Cometic Aramid fibre .094 thick and a set of Moroso . One of them better seal
 
There's way too many opinions on this subject. If you have a clearance issue and you actually have the Valve cover hitting the intake then you have to fix that. I've never seen this phenomenon in person but keep reading about people grinding their engine parts. C'mon really??? My take on all this is that the bolts are being overtightened. Cork is all I ever use. Hand tightened with a 1/4 inch ratchet. 35 years ago my Shop foreman showed me a fool proof way to install valve covers. #1 start with valve covers that FIT the engine. #2 if they are bent on the edges, STRAIGHTEN them. #3 use 3M yellow Weather Strip adhesive to secure the Cork to the Valve cover including a circle around each bolt hole. Let the Cork set-up for 1/2 hour or so. #4 install the valve covers with no adhesive or sealer on the head side. Evenly torque them with a 1/4 ratchet or use a torque wrench using the Spec in your shop manual.
 
I agree with Fishy - the stock gaskets are rubber usually. I have had no luck with them, and I really hate using all silicone, even if most cars nowadays are going that way. I bought the cork gaskets and put a film of silicone on them. As I said, not a leak all year and I have 4600 miles on my new odometer.
 
OwdKasd said:
There's way too many opinions on this subject. If you have a clearance issue and you actually have the Valve cover hitting the intake then you have to fix that. I've never seen this phenomenon in person but keep reading about people grinding their engine parts. C'mon really??? My take on all this is that the bolts are being overtightened. Cork is all I ever use. Hand tightened with a 1/4 inch ratchet. 35 years ago my Shop foreman showed me a fool proof way to install valve covers. #1 start with valve covers that FIT the engine. #2 if they are bent on the edges, STRAIGHTEN them. #3 use 3M yellow Weather Strip adhesive to secure the Cork to the Valve cover including a circle around each bolt hole. Let the Cork set-up for 1/2 hour or so. #4 install the valve covers with no adhesive or sealer on the head side. Evenly torque them with a 1/4 ratchet or use a torque wrench using the Spec in your shop manual.
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Wrong. With no bolts at all, just setting a MP valve cover on my Edelbrock RPM air gap or my Super Victor had them riding on the intake runner. I tried my Moroso fabricated aluminum valve covers and it is the same way. Don't ask me why, but it's not the first time I've seen it and it probably won't be the last. It's a Mopar thing.
 
Mopar to ya said:
Wrong. With no bolts at all, just setting a MP valve cover on my Edelbrock RPM air gap or my Super Victor had them riding on the intake runner. I tried my Moroso fabricated aluminum valve covers and it is the same way. Don't ask me why, but it's not the first time I've seen it and it probably won't be the last. It's a Mopar thing.
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Like I said
OwdKasd said:
If you have a clearance issue and you actually have the Valve cover hitting the intake then you have to fix that. .
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I guess you didn't read my post before saying I'm Wrong. I've installed Thousands of Valve covers the way I stated above with no comebacks.
 
sixty9xtc said:
If you go with RTV only I would suggest Right Stuff it is a very good sealant and it is ready to go as soon as you bolt down the valve cover. You don't have to wait for the sealant to set up. http://www.permatex.com/brand_right_stuff.htm
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I like this stuff in certain situations. Not in this case because the Engines already in the car. Too much chance of getting buggered up going back on. The other drawback is getting a perfectly uniform "Bead" so a thin spot could result in a leak. I honestly don't have the Patience/skill to run a perfect bead. But I know people that won't use anything else and they never have a problem.
 
71swing said:
Yeah, I've never have used the ends. Was taught from the beginning to only use RTV. I have an airgap and it has always had a good sized gap in the front valley. I have never been able to get it to seal correctly. May be in the market for a M1 this time around.
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That's odd. I've had 2 Eddy Air-gaps on 2 different engines and had no problem with either. As for the gap, I might be wrong but I would think it'd be the same with the M1. But you never know for sure with aftermarket parts until you try them.
 
OwdKasd said:
I've never seen this phenomenon in person but keep reading about people grinding their engine parts. C'mon really??? /QUOTE]

Yep, really! It's a well known problem with Mopar Perf. aluminum valve covers for LA engines. Do a search on here, Moparts, or most any Mopar tech board and you'll find it mentioned. Haven't had the issue with a magnum head engine, just LA engines. I suspect part of the problem might be due to a lot of our older LA heads have been around so long it's very possible most have been milled, possibly more than once. Plus it's really rare to see a stock intake on an engine with these covers and as you know aftermarket intakes generally have taller runners making the issue more profound.
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fishy68 said:
OwdKasd said:
I've never seen this phenomenon in person but keep reading about people grinding their engine parts. C'mon really??? /QUOTE]

Yep, really! It's a well known problem with Mopar Perf. aluminum valve covers for LA engines. Do a search on here, Moparts, or most any Mopar tech board and you'll find it mentioned. Haven't had the issue with a magnum head engine, just LA engines. I suspect part of the problem might be due to a lot of our older LA heads have been around so long it's very possible most have been milled, possibly more than once. Plus it's really rare to see a stock intake on an engine with these covers and as you know aftermarket intakes generally have taller runners making the issue more profound.
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Oh I believe that people are making parts that don't fit. I just cant' see myself grinding aftermarket parts to make them fit but if that's what it takes.... The Milling factor is exactly what I was thinking was the cause. I guess I would rather just send/Take back the Valve covers and use stock ones.
Also, I know for a fact that intakes have a slight bit of tolerance from left to right. Meaning that you can cheat them a little bit from left to right. That being said, Maybe that's why sometimes the VC only hits on one side. I would test fit everything gradually as opposed to bolting down the intake first and then trying to add the Valve cover's. Like I said I believe the clearance issue is real but The last thing I would try is Grinding. Especially a New part.
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Roy, I know it seems like we're getting off topic and arguing about unrelated topics. Sorry for that!

My intent is to help you get your oil leak fixed. I can't see exactly what you got but some say Grinding is the answer. That would be my last resort. I believe the Right Stuff would work if you had the Patience to apply a nice thick and Uniform Bead. Keep in mind that thicker Beads take longer to set up and dry/cure. Maybe a combination of Cork and Right stuff would be the ticket. The best I can tell you without seeing it is try to identify the clearance issue if any and use some trial and error.
 
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