Topic: Still leaking oil

[mikerider]

So I've  replaced the pan gasket and torque it down to 25 lb. The i changed the oil with a new filter. Torque it down.  And,,,,it still leaks.  Not as bad as it use to but still leaks.  I'm afraid to tighten the oil pan down any tighter because I might strip it out.  What do I do now?

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[denward17]

First off, 25 ft lbs is probably too much for an oil pan bolt.

What bike?

[piefairy]

You may want to give it overnight and recheck it. Soaking a new gasket in oil will let it swell a little, it may tighten up overnight.

[HondaMan]

Do you have a genuine Honda O-ring around the oil filter's housing? They are 4.5mm thick, not the 3.5mm thick ones found in oil filter "kits" by non-Honda vendors. You can't tighten it enough to make the oil filter then stop leaking without also distorting (or outright cracking) the oil filter housing.

[rotortiller]

First off, 25 ft lbs is probably too much for an oil pan bolt.

OP did not say ft/lb. Could be 25 in/lb which is too little and would potentially cause a leak considering 75 in/lb is about what it should be tightened to. I'd think 25 ft/lb would strip threads.

[PeWe]

Do you have a genuine Honda O-ring around the oil filter's housing? They are 4.5mm thick, not the 3.5mm thick ones found in oil filter "kits" by non-Honda vendors. You can't tighten it enough to make the oil filter then stop leaking without also distorting (or outright cracking) the oil filter housing.

I have ordered o-rings separate.
50 pack of ID 89mm, 4.5mm thick.
I use same size of o-ring around the bolt as the oil line attachment, 15 x2.5mm, tight fit.

My CB750 K2 got a thicker o-ring at last oil change. 5.0mm thick, ID 88mm. Perfect fit. Only 90km so no real practice yet.

I might order a bigger pack. 50 pcs cost not much more than 25

I tighten the M6 bolts for the oil pan with max 7.5Nm (5.5 ft lb).
I have 2-3 mm longer bolts to use the thread lenghts.
I have stripped too many threads over the years.

 
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Old oil filter I ordered from Yamiya some years ago had a 4.6mm thick o-ring!

[jaytee-nz]

His oil pan is leaking, NOT his oil filter.

[MauiK3]

Have to look for cracks, damage, defects in the engine side of the o ring contact surface.
A hairline crack may be hard to spot. Thorough cleaning might make it show up.

[HondaMan]

If a 750 oil pan is leaking, there are 3 causes I have seen:
1. Scratch (I call them "divots") in the engine's lower crankcase. These can be caused by many things, the more common I've seen being someone removing the oil pan to pull the engine (bad idea unless it is also further protected by a shield of some sort) and the gasket surface then hit the raised-edge lower engine bolster on the right lower front frame mount.
2. Damaged oil pan gasket face.
3. Leaking large O-ring in the oil filter, when the oil from that drip blows back over the oil pan and then drips from the pan.

[bryanj]

I give in WHAT BIKE?

[newday777]

If a 750 oil pan is leaking, there are 3 causes I have seen:
1. Scratch (I call them "divots") in the engine's lower crankcase. These can be caused by many things, the more common I've seen being someone removing the oil pan to pull the engine (bad idea unless it is also further protected by a shield of some sort) and the gasket surface then hit the raised-edge lower engine bolster on the right lower front frame mount.
2. Damaged oil pan gasket face.
3. Leaking large O-ring in the oil filter, when the oil from that drip blows back over the oil pan and then drips from the pan.

4. Some monkey over tightened the drain bolt and cracked the pan.
That's what I found on my K5 when I got it 7 years ago.

[HondaMan]

If a 750 oil pan is leaking, there are 3 causes I have seen:
1. Scratch (I call them "divots") in the engine's lower crankcase. These can be caused by many things, the more common I've seen being someone removing the oil pan to pull the engine (bad idea unless it is also further protected by a shield of some sort) and the gasket surface then hit the raised-edge lower engine bolster on the right lower front frame mount.
2. Damaged oil pan gasket face.
3. Leaking large O-ring in the oil filter, when the oil from that drip blows back over the oil pan and then drips from the pan.

4. Some monkey over tightened the drain bolt and cracked the pan.
That's what I found on my K5 when I got it 7 years ago.

Yeow!

[Little_Phil]

I give in WHAT BIKE?

It's a 550F. He has a post further down.
They are 6mm flange bolt so suppose the torque is 7.2ft lbs as per the manual. But I only ever tighten them by feel. The O ring does the work. But I have been known to put the slightest smear of Threebond on it.

[Kelly E]

I tighten small bolts by feel using my Plumb 6" by 1/8" 1/4" drive extension that will start to twist before the aluminium threads strip out. Otherwise anything under 20ftlb I use an inch/pounds torque wrench.

[bryanj]

Two most common causes of leak there on 500/550 are O ring or groove damaged, casing cracked

[HondaMan]

Another 'cause of weeps' I've found in the 500/550/350F gasket kits is" under-thickness O-rings - specifically on the oil pan and the top cam cover. They are about 0.1-0.2mm thinner than the OEM versions of those 2 large O-rings.

Someday I'm gonna figure out just how big those O-rings are, and get some made - thicker. While they will be round and not molded, they will seal better if it goes according to plan?