oil leak from front engine cover

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Aug 6, 2017
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Grand Rapids, MI
Getting an oil leak from the front engine cover near the top of the coolant pump. 2005 ST1300 with 32000 miles. I got this bike a month ago and since I didn't know its history I wanted to do a thorough service. I've checked valve clearance, replaced plugs, and was doing a coolant flush when I noticed oil running down around the clutch housing coming from an opening above the coolant pump. I've run this bike hundreds of mile since I got including a track day and haven't seen any signs of a leak before.
Since this cover is over the very front of the oil pan I wonder if this is just a leaking cover gasket or if I have a real problem?
This is my first Honda so I don't have any experience with these bikes beyond this service session.
From what I've read so far oil leaks are not common with these bikes so I'm concerned.
Any ideas?
 
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If it was not leaking before your valve service (clearance checking), then you probably pinched the v cover gasket when you fitted it. There was a recent thread about this - I've never done it so I suggest you search for valve cover gasket in the search box, and/or oil leak.
You need to use gasket sealant at some point and then carefully fit the covers. This is all described in the service manual as well as more thoroughly in those other threads.

As a last resort you might PM Larry - Igofar - and talk to him. While I'm sure he will be more than happy to help you, I hesitate to bother someone when there is a lot of info here for the looking.
 

Mellow

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Getting an oil leak from the front engine cover near the top of the coolant pump. 2005 ST1300 with 32000 miles. I got this bike a month ago and since I didn't know its history I wanted to do a thorough service. I've checked valve clearance, replaced plugs, and was doing a coolant flush when I noticed oil running down around the clutch housing coming from an opening above the coolant pump. I've run this bike hundreds of mile since I got including a track day and haven't seen any signs of a leak before.
Since this cover is over the very front of the oil pan I wonder if this is just a leaking cover gasket or if I have a real problem?
This is my first Honda so I don't have any experience with these bikes beyond this service session.
From what I've read so far oil leaks are not common with these bikes so I'm concerned.
Any ideas?
Yup, since you did to a valve check, it's fairly common to accidentally pinch the gasket. 1st thing to check.

Also, if you use sealant on the gasket you ONLY need it in the corners of the half-moon parts of the gasket that is positioned towards the front of the bike.
 
OP
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Grand Rapids, MI
Thank you Mellow & SMSW however this is not a valve cover gasket leak. The oil is coming from the front crankcase cover just below the coolant pump on the left side (not the coolant pump weep hole) where the separation between the crankcase cover & the coolant pump meet. There is a small opening there where the oil is coming from. The cover doesn't appear to be cracked; I've removed it to look for any cover damage.
 
OP
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Just got the Water Pump cover off the Crankcase Cover. I'm guessing I have a Water Pump oil seal leak. Looks like I'll have to take the Crankcase Cover to the dealer to have the seal replaced as I don't have access to a hydraulic press. Don't know how that happened based on what I've done with the bike up to this point.
 

dduelin

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32,000 miles is way early for a water pump seal. If the leak is coming out the square hole near the water pump weep it's oil coming down from above, from the vee area between the cylinder heads. If you just checked the valves easy money is on a pinched valve cover gasket. That's a zero $ repair to look for first and it happens to many many many of us the first valve check.
 

STumped

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32,000 miles is way early for a water pump seal. If the leak is coming out the square hole near the water pump weep it's oil coming down from above, from the vee area between the cylinder heads. If you just checked the valves easy money is on a pinched valve cover gasket. That's a zero $ repair to look for first and it happens to many many many of us the first valve check.
+4

Very easy to overlook.
 

Blrfl

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Have to agree with Joe and Dave; I think you're barking up the wrong tree.

The only place the water pump comes into contact with oil is on the engine side of the seal, and the path of least resistance for that to get out is the weep hole on the right side. If the seal were to fail catastrophically, you'd have oil in your coolant and coolant in your oil. (Sounds like a Reese's ad, doesn't it?) Other than that one spot, everything else under the housing is coolant, and these bikes don't have a history of having that part of the pump spring a leak.

If the heat mat wasn't kept out of the way while the valve cover was being installed (been there, done that) or the bolts weren't torqued down in the proper order, you'll get a leak on the left side.

--Mark
 
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Before you start ripping stuff off the engine, I would check a couple things first. It sounds like your talking about the SQUARE hole, which is where anything up in the V area drains to. While it could be a oil seal, it could also be the mystery plug (galley oil plug under T-stat housing) or coolant with road grime mixed in, looking like oil. If I is in fact really oil, another place you may check is the spark plug wells. They each have a drain hole under neath the muffler area (very near where your describing) and if you pinched or didn't seat the rubber head gasket around the spark plug area, this will leak into the plug well, and exit at the drain below the muffler.
Perhaps you can take and post a picture of what your seeing that may help us help you.
 

larryg

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I had an oil leak recently, also after checking valves. Turned out that I had missed installing one of the sealing washers on the valve cover hold-down bolts. Apparently it fell out of the cover and I missed it. Felt pretty foolish about it, but was easy to fix. Look carefully at all 6 valve cover bolt heads, if one is set in slightly lower - that's it.
Good luck....
 
OP
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Because of the number of replies suggesting a valve cover leak I removed the valve covers & rechecked everything but could not find any evidence of a leak. I'm not sure if that is a good thing or not so good? I did find a dried out mushroom between the cylinder heads, very strange!
I have removed the crankcase cover & find the water pump impeller turns with some resistance; is that normal? (I'll post that question on another thread but I discovered it while trying to find the source of an oil leak)
 

SupraSabre

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Because of the number of replies suggesting a valve cover leak I removed the valve covers & rechecked everything but could not find any evidence of a leak. I'm not sure if that is a good thing or not so good? I did find a dried out mushroom between the cylinder heads, very strange!
I have removed the crankcase cover & find the water pump impeller turns with some resistance; is that normal? (I'll post that question on another thread but I discovered it while trying to find the source of an oil leak)
And I hope you DIDN'T drop the little Waterpump sprocket and chain back behind the clutch! :eek:4:

If the water pump is failing, you will get oil out through the round hole! If it is leaking else where, it's not the waterpump. I've replaced two waterpumps myself and they were both leaking out the round hole. I have another one to do, but that's for after I work on one of my other ST1300s.

If the oil was coming from under the front waperpump "cover", chances are the leak (oil or coolant) is coming down from the "valley" or better known as the Abyss. That would indicate a coolant leak or possibility that boltplug Larry was talking about.

I think Honda got tired of the dealers doing waterpumps under warranty, when they weren't needed, so one thing they added to the 8+ models was a tube for the waterpump round hole, so it would drain under the bike when it failed. If the leak was small enough, it would evaporate before the end of the tube. I'm sure they have saved thousands with that one little fix!

One other thing, when you have questions about stuff like this. post a picture of it, it would help the "community" identify the leak better.

Good luck!
 

JohnK

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Before you start ripping stuff off the engine, I would check a couple things first. It sounds like your talking about the SQUARE hole, which is where anything up in the V area drains to. While it could be a oil seal, it could also be the mystery plug (galley oil plug under T-stat housing) or coolant with road grime mixed in, looking like oil. If I is in fact really oil, another place you may check is the spark plug wells. They each have a drain hole under neath the muffler area (very near where your describing) and if you pinched or didn't seat the rubber head gasket around the spark plug area, this will leak into the plug well, and exit at the drain below the muffler.
Perhaps you can take and post a picture of what your seeing that may help us help you.
don't forget the bond!!! - learnt that the hard way - (Dr Larry fixed that!)
 
OP
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Solved, finally. Turns out the leak was due to a broken valve cover gasket that I must have torn when reinstalling after the valve check. The bike had to be warmed up and running for me to detect where the oil was coming from. I didn't notice any oil while the engine was cold. Thanks to all who replied to help a newbie learn.
 

SupraSabre

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Very good! Since simple fix and you didn't have to take that front cover off! :D
 
OP
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I had taken the front cover off because I thought the water pump was a separate part behind the cover & thought that was where the leak was coming from. I had to replace the gasket behind the cover but that was the only part I had to replace. A very time consuming lesson but not monetarily outrageous. The worst part of the job to me was all the Tupperware, especially during reassembly. Being new to Hondas I appreciate the wisdom found on this site.
 
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