Adventures in chasing an oil leak.

[Trent Von]

Adventures in chasing an oil leak.

After months of chasing down an oil leak it ended up being the one thing that most people said it wasn’t…

The leak was dripping from the front of the oil pan (that I knew), but the “look see” at what what it could be techniques of checking the timing belt always came up dry (no oil on the belt), must mean the seals are holding….. the search continues.

I thought to myself it’s gotta be the oil pan gasket, or maybe the breather tube. I replaced them both to no avail, just kept dumping oil, now 1qt per gas tank.

So I look at the timing belt again… still dry. Perhaps it’s the valve cover gasket, change it… still leaking. PCV valve?, nope… still leaking.

(….. to be clear, the car was really LOVING all the preventative maintenance I did. All kinds of power and MPG was better.... just leaving puddles of oil everywhere. However, I did get into a good routine of checking the dip stick everyday)

So I look at the timing belt cover a bit closer and I noticed a little drip spout at the lowest part of the timing belt cover. Could it be? I tried everything else. So I ordered a new timing belt and oil pump along with a crank seal.... then dug in. Once I got behind the timing belt it became oblivious, that cranks seal was flooded with oil. I pulled the seal and it was as hard as a rock with a huge crack... that thing was toast.

So I replaced crank seal, no more leaks…..

Most engines (in my experience) have timing belt covers that seal off the entire front of the engine… so if you get a crank seal leaking the result is the timing belt gets soaked. Honda knowing this designed a drip spout behind the timing belt pulley and flange… So if the crank seal fails the oil gets never contaminates the belt. GOOD ONE HONDA!

Hopefully this is helpful to someone who may be trying to track down a phantom oil leak

[ShiRen]

My guy, front main seals go out just as often as the rear. Main seals should always be changed when they are taken apart for a clutch or timing belt.

Meanwhile, I've put 3 cam seals in my car and it still leaks... invest in some hondabond to go around that one.

[Trent Von]

I suppose so, I guess the moral of this story is.....

..... for as many times as I ask around for some oil leak advice the same thing came up for main seals;
(1) rear seal, check around the bell housing
(2) front seal, check timing belt; wet oil soaked belt inspect cam seal and front main.

Although this might be sound advice on practically every make and model of car, the point of this post was to advise people on what to look for a when diagnosing a HONDA. It was almost hysterical how much I got stuck in a diagnostic loop! Due to a small bit of over engineering the "timing belt test" wont tell you the whole story with a 3rd gen Accord

So my timing belt was protected as I poured a quart of oil per 300 miles. Kind of cool when you think of these little touches that Honda does that in all reality didn't need to be. With that, you may get fooled if you go with traditional diagnosis techniques.


As far as "seal per belt", I've never had someone tell me to change the front seal with a timing belt, that's a new on me. If anything I've always heard to leave the seal alone unless you've got a leak. The last seal lasted 250k before the first drip.... so a "seal per belt" might be a bit excessive. With that said, it sounds like good advice every 3rd belt and/or 2nd clutch

[Trent Von]

BTW, the health of the car is excellent.
1986 Accord LXi
387k miles (note, this oil leak story was from 5 years ago)
No mods, all original equipment
Oil consumption is around quart per oil change cycle (2.5k miles),
32 mpg
And I got the AC working again! WINNING

[Dr_Snooz]

Glad you got it figured out. Now you can park on the driveway again lol!

It's a best practice to replace the crank seal, cam seal and water pump with every timing belt service. It isn't a bad idea to reseal the oil pump and replace the tensioner every other job or so as well. It's cheap insurance when you factor in how difficult it is to get to them. Just don't use those crappy steel universal seals from National that O'Reilly likes to sell you when you aren't paying attention. They don't seal right and you'll get to redo the job.

[ShiRen]

[QUOTE=Trent Von;1223757As far as "seal per belt", I've never had someone tell me to change the front seal with a timing belt, that's a new on me. If anything I've always heard to leave the seal alone unless you've got a leak. The last seal lasted 250k before the first drip.... so a "seal per belt" might be a bit excessive. With that said, it sounds like good advice every 3rd belt and/or 2nd clutch[/QUOTE]

How often do you replace your timing belt? Its usually a 50-100k mi part, so that would mean prime time to change the $3 seal. Clutches go a lot faster for some people, and they can't be ignored, so not replacing the rear main seal would just be negligent, unless you plan on putting another clutch in less than 50k mi yourself.

[GreyACR]

Good diagnostic! This should be a good future reference.