The International Cessna^® 170 Association

I know this subject has been discussed on the forum, but I guess I need some basic tutoring on what words to put in what blanks and any other things that may or may not need to be checked in order to search for a particular subject. Yes, I am computer challenged

I don't guess most things on our senior airplanes happen "all of a sudden", but sometimes it seems they do. All of a sudden I seem to have 3-4 cylinders that are leaking oil from one valve push rod tube. Appears to be the most aft one on at least 3 of them (don't think it is because that tube is lower than the other one, but could be). I thought the drip was from only one until I did a run up today to ck for leaks after an oil/filter change. WRONG At least 2 cylinders are dripping on the left and one or two on the right, but left is more pronounced. Appears to be leaking where the tubes mate with the cylinder head, not where the tubes go into the crankcase. Question--is there any rational reason why this seems to have developed within a fairly short time frame (2-3 months)? Is there any "simple" way to correct this condition? Annual comes up in February and that might be the time to address the problem. I don't suppose the association has one of those tools that can be used to tighten the tubes

The most effective way I have found to deal with leaking push rod tubes is to replace the orginal push rod tubes with the Real Gasket Push Rod Tube Kit - see http://www.realgaskets.com Cost for parts is about $77 per cylinder - installation is relatively simple.

The standard method of correcting oil leaks at the push rod housing/cylinder head juncture is to use the special swaging tool, designed for the job, to expand the push rod housing from the inside. Any good engine shop and many A&P mechanics that work on O-200 and
O-300 engines should have this swaging tool.

Robert Eilers wrote:The most effective way I have found to deal with leaking push rod tubes is to replace the orginal push rod tubes with the Real Gasket Push Rod Tube Kit - see http://www.realgaskets.com Cost for parts is about $77 per cylinder - installation is relatively simple.

Even these are not immune to leaks. I had them put on my new cylinders 85 hours ago and three tubes were leaking already. The difference is they can be removed and re-sealed without pulling the cylinder.

Got the Real Deal and they're very effictive. 2x I had the rubbers that connect the tubes to the lifter covers slide back and pumped 5 qts out the first time and 2 qts the second time before catching it in flight.

rbarry wrote:Got the Real Deal and they're very effictive. 2x I had the rubbers that connect the tubes to the lifter covers slide back and pumped 5 qts out the first time and 2 qts the second time before catching it in flight.

Effective - how? Sounds pretty bad to me!

Today I read where Continental, on their "new" O-200 for the SLSA airplanes, is now using a removable, spring loaded, push rod housing. Since the O-200 and the O-300 use a common cylinder, I would expect the new housings would be applicable to our engines too.
Hopefully, competition will bring the price down. It sure did on cylinders.

Ya that didn't come out right. The old push rod tubes were the ones that caused the problem when the rubber seal backed off of the lifter housing. this happened 2 x. I corrected the problem using the R.G tubes. I've got no leaks from that area anymore.

The "Real" mod, and the latest TCM mod is actually adaptations of the system used on all the larger Continentals.

Frank, I own the "swaging tool" to correct the leaks and I'll bring it to DFW area on Saturday and find a way to get it to you over the next few days, OK? It's pretty simple fix and can be done during your annual. Takes about 30 mins per cylinder.

Reasons for suddenly developing such leaks can usually be traced to improper handling of the engine inadvertently during other repairs (someone grabs and moves the tubes while working on some other issue.... uses one to "pull oneself up from the hangar floor", etc. They are NOT braced at their inboard ends even when the cylinder is mounted.... and someone grabs or moves one when replacing exhaust parts, etc., ...a common error.)