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Valve cover leak - 9th try by Gizmoman on 11 Jun, 2014 05:58
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I have a valve cover that leaks on the left rear corner - Vanagon 500, standing behind van looking forward.
After nine attempts to stop it, it still leaks.
The cover is flat
Surface of cover looks like new and it's not twisted. I have also inspected along the entire edge to insure there is nothing hitting once it's tightened down.
Head is new KS
Gasket is the third one, still looks like new
Tried High Tack Permatex, Black, high oil resistant oil RTV, Copper form-a-gasket, Ultra grey RTV
Dabs in the corners of the cam cap (of most of the above).
A thin coat along the entire bottom edge (of most of the above)
My last attempt was clean, clean, clean (using acetone) and no sealer at all. This seems to be the best seal yet but it still leaks.
On every attempt I let it sit overnight before starting it up (except the last one because there was nothing there to cure).
My next attempt may be hylomar or the permatex equivalent "Perma-Shield". Silicone (RTV) is good at filling bad/porous surfaces but I have none. I wish I had never put it on there because I actually think it made things worse. You can never completely remove it without wire wheeling or sanding the surfaces. Also, silicone is very slippery and I fear it has made it impossible to seal. Hylomar on the other hand is urethane based and would have sealed much better but it may be too late now.
For some reason. my old head had six taped holes around the perimeter which would have been for the cast cover - I wish this one did as well.
Has anyone ever had to buy a new cover (if they are still available) that fixed the issue. I know a lot of you have had no problems with this. I am looking for those that have, and found a fix I haven't tried yet. -
#1 by vanbcguy on 11 Jun, 2014 06:39
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I'm going through the same thing on my AHU right now, which uses the same style of cover. I actually went so far as to spend the $$$$ and buy a new valve cover, but I still have leaks.
From what I've read the cover, head and gasket need to be bone dry. If any sort of sealant is used (other than at the ends of the cam caps) supposedly the gasket squishes around out of place. In my hunting around for the "fix" to the AHU gasket I didn't find anyone having success using anything other than adhesive-type products to keep the gasket in place but I haven't gotten there yet myself. -
#2 by Jetmugg on 11 Jun, 2014 06:45
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Not sure if it helps your application or not, but on my 1.5L / 1.6L / 1.9L Frankendiesel, I used the Hylomar spray on the oil pan and valve cover gaskets (just 2 light coats on each gasket surface), and the result was absolutely no leakage.
I feel like it's easy to get uniform coverage with the Hylomar spray, whereas it's more difficult to achieve even coverage with RTV type products that don't want to spread evenly.
Steve. -
#3 by 92EcoDiesel Jetta on 11 Jun, 2014 12:32
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have you been able to identify exactly where it is leaking from? Is it from the flat mating surfaces or from bolt holes? My guess is the bolt holes.
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#4 by vanbcguy on 11 Jun, 2014 16:36
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AAZ valve cover has no perimeter bolts, just the 3 center ones.
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#5 by Gizmoman on 11 Jun, 2014 17:36
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Well, I guess misery loves company.
I'm going to spring for a tube of Hylomar and put a light coat on all surfaces. Agreed the the spray gives a good even coat, however, spraying the head while its in the van would take a serious masking job unless I want a lot of stuff blue and sticky
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I wish the FLAPS carried it but they seem to be stocked up with chrome skull door lock knobs and spinning hub-caps.
Vanbcguy, are you running the stock hockey-puck breather?
Reason I'm asking is I had to make my own as my "custom" intake manifold is in the way of the stock one. It's now a can type affair stuffed full of stainless steel scrubber pads and vents to a catch bottle. When I blow through the contraption there is slight resistance. When I blow through the stock breather/hockey puck, there is none at all. Possibly I am building a bit of crankcase pressure which is making it leak. -
#6 by 92EcoDiesel Jetta on 11 Jun, 2014 20:37
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AAZ valve cover has no perimeter bolts, just the 3 center ones.
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Is it possible oil is leaking out of the 3 center bolts, or from elsewhere, dripping wicking to where it "appears" to be leaking? If the valve cover and head is perfectly flat and the gasket is well made, hard to imagine it leaking there, especially after 9 attempts. -
#7 by Gizmoman on 11 Jun, 2014 21:43
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I have rubbed my finger tips over everything more times than I care to admit, the wife would be jealous. Rub, look, touch, look, you get the drift. I'ts the cover, along the lower edge where the oil rally flows - probably looks like Niagara Falls in there. The three flange nuts and related bits under them are bone dry.AAZ valve cover has no perimeter bolts, just the 3 center ones.
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Is it possible oil is leaking out of the 3 center bolts, or from elsewhere, dripping wicking to where it "appears" to be leaking? If the valve cover and head is perfectly flat and the gasket is well made, hard to imagine it leaking there, especially after 9 attempts.
My guess, is possibly pressure as I mentioned earlier. As soon as I get back to it, I'm gonna remedy that and see what improves. -
#8 by vanbcguy on 11 Jun, 2014 23:05
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Yep, I have the factory breather system in place.
I have mine down to a very light leak on one corner, which I will admit I got a vacuum line stuck under briefly while putting the cover on last time. That may well be the source of my issues at the moment.
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#9 by Renax on 12 Jun, 2014 03:00
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Try to overtorqe the bolts? Maybe the cover is a bit bent out of shape so you need to get the center a bit lower than stock?
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#10 by vanbcguy on 12 Jun, 2014 07:23
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With these covers the nuts go down flush with the cam cap, compressing the various rubber seals around the bolts in the process. You can't torque them any further. The design prevents damage due to overtorque.
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#11 by Gizmoman on 12 Jun, 2014 17:12
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With these covers the nuts go down flush with the cam cap, compressing the various rubber seals around the bolts in the process. You can't torque them any further. The design prevents damage due to overtorque.
Good to know you cant over-torque them.
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I built a wooden support fixture and turned a chunk of steel to match the concave surface inside the cover. Then I pressed them out a bit checking several time for changes. The goal was to insure the perimeter sealed before the bolt rubbers.
I ordered a tube of Hylomar yesterday and will also insure my DIY vent has no back-pressure. I'd say that with the Hylomar and removing the slight back pressure should solve the issue but after nine tries, all bets are off till proven.
It will be next week before the hylomar arrives (can't ship fast due to chemicals) -
#12 by GEE-BEE on 12 Jun, 2014 18:48
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Did you use the Victor Reinz mfg ?
http://www.ebay.com/itm/Engine-Valve-Cover-Gasket-Set-Reinz-WD-EXPRESS-fits-96-97-VW-Passat-1-9L-L4-/121341851653?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AVolkswagen&hash=item1c4089b805&vxp=mtr#ht_1101wt_1206
I had no problem with mine, I did install and new cover thou
GB -
#13 by Gizmoman on 12 Jun, 2014 19:02
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Gee Bee
I used a Beck Arnley 036-1658 It looked pretty good though. I'll bet there's a high probability they both get them from the same manufacturer.
It sat in the shrink-wrap for a while and the loop over the cam cap was folder over. It fit fine though once in the groove.
A lot of guys have had success but most don't have the 50 degree vanagon install which isn't helping.
Also, I think I have a tiny bit of back pressure and have fixed that.
I'll keep everyone posted. -
#14 by Toby on 12 Jun, 2014 19:31
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Its not about the gasket. Most center bolt valve covers have these issues for exactly the reasons Vanbccguy said.
The easiest way to solve this is to use GOOD RTV used in the proper way. Much of it is crap for sealing engines. The ones marked "OEM grade" are far better than most of the others. The black stuff appears to be more rigid when set up than the gray. If it does not say OEM on the package, its not the right stuff.
The best way to seal any 2 surfaces is to use a bead of RTV and NO gasket at all, but this is not always practical. RTV is useless unless you get every trace of grease and oil and dirt off of both surfaces and keep them oil free for at least 24 hours, preferably more. Once RTV sets up it is impervious to almost everything you are likely to encounter in automotive use. Oil contamination before it is completely set will prevent it from ever setting up.
It is vital that all surfaces be completely oil free and ALL surfaces to be sealed must be coated with RTV. If you have just the tiniest skim coat on other surface before assembly it will not leak once set up. Coat one side only and sometimes little channels form in the RTV and you will have leaks. Coat both surfaces and you are golden.
You do not need a ton of RTV, just enough to seal, so gobbing on huge amounts just means that it will collect somewhere in the oiling system.
What has been said here about RTV and gaskets is spot on. Never use a gasket if you can help it. The factories don't. The RTV just turns into a great lubricant and the gasket usually spits out somewhere. If will often split down the middle between bolt holes. The proper procedure for sealing things with RTV when you cant eliminate the gasket is to coat all four surfaces with a light coat of RTV and then assemble the parts, BUT DO NOT TORQUE THEN DOWN. tighten them just enough to pull everything together. After the RTV has cured then torque every thing down. This will seal very well and not allow the gasket to spit out because is is glued in place.