{"id":2173,"date":"2020-03-01T13:20:52","date_gmt":"2020-03-01T18:20:52","guid":{"rendered":"http:\/\/mewagner.com\/?p=2173"},"modified":"2025-06-01T13:31:32","modified_gmt":"2025-06-01T17:31:32","slug":"oil-leaks-and-crankcase-ventilation-a-case-study","status":"publish","type":"post","link":"https:\/\/mewagner.com\/?p=2173","title":{"rendered":"Oil Leaks and Crankcase Ventilation – A Case Study"},"content":{"rendered":"

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The relationship between oil leaks, crankcase pressure and crankcase ventilation is a topic that has not been understood by the majority of the hot rodding community for quite some time.\u00a0 In this case study, we will show how Troy Cryer\u2019s \u201934 Ford suffered from oil leaks to the extent that the engine was pulled and rebuilt, only to have the same leaks crop up again.\u00a0 The issue was finally resolved by addressing the root of the problem \u2013 crankcase pressure that was the result of an inadequate PCV system.\u00a0 After installation of an M\/E Wagner Dual Flow\u00ae<\/sup> PCV valve, Troy\u2019s car is now oil leak free, and in his words \u201cI can finally enjoy driving my old hot rod again!\u201d<\/p>\n

Crankcase Ventilation Basics<\/strong><\/p>\n

The job of the Positive Crankcase Ventilation (PCV) system is to remove blow-by gases from the crankcase by vacuum and recirculate them via the intake manifold to be burned in the engine.\u00a0 If the engine is producing blow-by gases faster than the PCV system can dispose of them, an increasing surplus becomes trapped in the crankcase, causing excess pressure and inevitably,\u00a0oil leaks.\u00a0 Even the most carefully sealed gaskets can leak when confronted by rising internal crankcase pressure.<\/p>\n

A properly functioning PCV system will expel the gases from the crankcase faster than the engine produces them.\u00a0 This results in a low-level vacuum that draws in fresh air to the crankcase from the crankcase breather. \u00a0In 99% of normal driving conditions, this is how a properly functioning PCV system works. \u00a0The gasket\u2019s job is made much easier when the crankcase has vacuum pulling oil inward, rather than pressure trying to push it outward.<\/p>\n

Troy\u2019s Oil Leak Problem<\/strong><\/p>\n

Troy\u2019s \u201934 Ford had chronic oil leaks.\u00a0 The leaks first started around the valve covers, which leaked down the back of the engine and blew oil all over the undercarriage.\u00a0 At this time he was using a typical billet aftermarket PCV valve and billet breather, and Troy reports he would have to clean the engine off after driving the car only a few miles.\u00a0 Eventually leaks also developed in the pan gaskets and crank seals.\u00a0 As the problem got worse, Troy sought advice from a trusted mechanic as well as several other experienced hot rodders, but no one had certain answers.\u00a0 Everyone’s best theory at the time was that the rings could be faulty or installed improperly.\u00a0 The situation got bad enough that the engine was pulled, the cylinders were honed, and a new set of rings were installed along with all new gaskets and seals.\u00a0 In total, Troy spent over $2,000 in parts and professional labor on the rebuild.<\/p>\n

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After the freshened engine was put back in the car, the oil leaks returned much to Troy’s frustration.\u00a0 At this time, he was still using the same PCV system as before the engine was rebuilt.\u00a0 Troy replaced the valve cover gaskets many times on the rebuilt engine, trying numerous types of gaskets and sealants.\u00a0 He then tried replacing his PCV valve with another generic aftermarket billet unit.\u00a0 Nothing of these attempts worked.\u00a0 He started to suspect that the problem was not in the gaskets and seals as he originally suspected.<\/p>\n

The Solution<\/strong><\/p>\n

Troy says he never considered the influence crankcase pressure can have on oil leaks until he started to do research online, at which point he came across an article about our Dual Flow PCV valve. \u00a0It was, in his words, a \u201clightbulb moment\u201d.\u00a0 He called M\/E Wagner, and we helped him lay out a proper PCV system using our Dual Flow valve.\u00a0 Troy is happy to report that his oil leaks are now completely gone, and most importantly he can enjoy driving his car again.\u00a0 Looking back on the experience, Troy says “[…] it took a rebuild to learn the hard way.\u00a0 In hindsight, I was lost and searching for a needle in a haystack with blindfolds on […] While I’m thrilled to have these issues resolved, I cant help but wonder how much time, money and effort I could’ve saved myself if only I had known about your valve.”<\/p>\n

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Summary and Feedback from other Customers<\/strong><\/p>\n

M\/E Wagner\u2019s Dual Flow PCV valve is the only PCV valve on the market that can be tuned to meet the unique crankcase ventilation needs of each individual engine.\u00a0 To read more about how our Dual Flow PCV valve flows the right amount of air at the right times to keep the crankcase under a slight vacuum, read our flow test shootout.<\/a>\u00a0 Our customer\u2019s rides page<\/a> showcases enthusiasts from all over the world that have solved many issues through the use of our Dual Flow valve.\u00a0\u00a0Here are a few highlights of others who have solved oil leak problems just like Troy did.\u00a0 You can read excerpts from their testimonials below.<\/p>\n

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(1) It had some oil leaks, smell and the idle was a bit rough and difficult to tune. I changed the rear main seal two times, installed a billet retainer, tried various timing\/carb combinations but without success.\u00a0 With the M\/E Wagner PCV valve the problems are finally solved and the car idles incredibly smooth at 700 RPM.\u00a0 -Riccardo Fulgoni<\/p>\n

(2) Engine leaks and the driver smelling like 30w oil are a thing of the past. As a guy who has changed out the same gasket multiple times, I can tell you that engine leaks are quite often not a gasket problem but rather a crankcase pressure problem. The Wagner valve fixes the problem, not just the symptoms.\u00a0 -Allan Zolnekoff<\/p>\n

(3) Installing your PCV on the 40 completely eliminated the oil seepage from the breather and PCV grommets and also eliminated an oil leak from the rear of the intake.\u00a0 -Joe Gaddy<\/p>\n

(4) I had been trying to chase down a small oil leak prior to the addition of the Wagner valve, and that too, is gone.\u00a0 -Mike Okuley<\/p>\n

(5) How do I know it works? \u00a0Well first there is no oil sneaking by any gaskets. No weeping or seeping oil along valve covers. Everything is dry and I haven\u2019t seen that since the engine was built. The guys that built the engine for me said it wouldn\u2019t leak. The leaks were caused by an ineffective PCV valve. I tried a couple of different ones with varying pressures \u2013 although one was better than the other I still had oil seeping from gaskets but not as great. Once I installed and set-up the new Wagner PCV all was good after [\u2026] The other day I changed my oil and as I was crawling underneath my car I was looking for all the old oil leaks coming from the usual locations. Was gladly surprised to not to see one spot that had any oil on it.\u00a0 -Wayne Grotski<\/p>\n

(6) My problems were mainly oil leaks, not always in the same place, breather cap blow by, erratic and hard to adjust idles, dirty oil and moisture issues [\u2026] My oil always looked like it needed changing after 100 miles. I have 300 miles on the new valve and the oil still looks new. I don\u2019t see any evidence of moisture around the bottom of the PCV Valve and so far, no oil leaks are present. \u00a0-Rich Chiarenza<\/p>\n","protected":false},"excerpt":{"rendered":"

The relationship between oil leaks, crankcase pressure and crankcase ventilation is a topic that has not been understood by the majority of the hot rodding community for quite some time.\u00a0 In this case study, we […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":2201,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":{"0":"post-2173","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-pcv-tech"},"_links":{"self":[{"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/posts\/2173","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mewagner.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2173"}],"version-history":[{"count":22,"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/posts\/2173\/revisions"}],"predecessor-version":[{"id":2733,"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/posts\/2173\/revisions\/2733"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mewagner.com\/index.php?rest_route=\/wp\/v2\/media\/2201"}],"wp:attachment":[{"href":"https:\/\/mewagner.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2173"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mewagner.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2173"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mewagner.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2173"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}