Oil Filler Cap too tight

[jonflies]

Noticed my cap was too tight, last time I had to add some oil, so I bought a replacement cap from the local parts store. Wasn't too hard getting the new one on, but then next time I had to add oil, I could hardly get the thing off again. Pretty sure it's a swollen O-ring problem. Anybody have suggestions for o-ring composition and size, to save me some time?

[tom.mcinerney]

Some sites of possible interest:
http://www.oringsusa.com/html/how_to_select.html#EXECUTIVE-SUMMARY
http://www.accurate-prod.com/products.htm
http://www.accurate-prod.com/elastomers.htm
www.silastic.com. (http://www.silastic.com.)
Tradename "viton" extremely resistant many solvents.
Don't know size here. Try ask dealer for part No., their book sometimes lists size. Otherwise bring to an 'oring' dealer to size.
Post back (with cure) if solve problem.
Did install oring dry or wet with lube oil?

[jonflies]

I've already contacted the dealer, who indicates his book only shows a new cap with O-ring, but not the o-ring separately.

I've searched a few of the O-ring suppliers, including the references you've sent. The sizes they have are either the same or too small, plus, if I want to buy, the quantities are too high.

Had the O-ring measured. 1.109 ID and thickness (which they call width) is .212

I still cannot believe I'm the only one with this problem.

[tom.mcinerney]

Sorry, Jon. Less than a year ago i ordered just two fluorosilicone orings to replace those sealing the heater of my fuel conditioners. Apparently since then they (oringsusa.com) decided not to bother with such small orders!

If you still have two caps, maybe try easing the pressure on the clamping ears of one??

OK, you might be able to get what you need at Mcmaster's:<http://www.mcmaster.com/>. On their home page, you see categories like, "Pipe, tubing, hose and Fittings", "Plumbing and Janitorial"...GOTO the second from last category on right hand side of page-"Fastening and Sealing". Now notice that the third-to-last subcategory within that range is labled, 'O-Rings'. Click there. Click on orings next page. Suggest scroll down to "Type" {should be called 'material, or composition}. Suggest look under 'Kalrez', 'Silicone', or 'Viton'. Then select size. If go with either of latter two compositions, can get 25 pack for about $12 plus shipping. A single kalrez ring costs, well, too much...
Good luck; if find better site fer small oring orders, please advise!

[Beedee]

Just a thought, but have you tried greasing the "O" ring. they are kind of like an oil filter, if you put it on dry, you will have a hell of a time getting it off

[jonflies]

Thanks for the advice. This cap is the plastic type, without ears. Instead it has a slot and groove design. By aligning the slots with the nubs, found inside the down tube, and turning the cap, it is pulled into the tube, locking at 90-degrees.

I have sent requests to O-ring companies. Hopefully that will turn up something.

[gmctd]

The oil filler cap is designed for tight fit, enabling the CDR system to be functional.
Leaks here can be disastrous, where the fan is pulling dust, dirt, and etc from frontal traffic conditions.

The o-ring is intended to be lubed prior to installation - un-lubed rubber is highly frictional.

O-ring failure would be from heat-hardening, not oil impregnation\swelling\softening.

Lubricate the o-ring with engine oil before installation - if it still fits tight, be thankful. ;)

[jonflies]

Thanks for the lubrication hints. Yes, the O-ring is slippery, as I oiled it prior to install, but still takes two hands to pull it off. I think less crush on the O-ring is possible, while still allowing a good seal.

[DmaxMaverick]

Just a notion out of left field....

Have you tried installing the cap without the oring on it? (just for testing, not running)

If it is still tight without the oring, then.... It should be pretty loose without it. I know some of them can be kinda' snug, but I haven't seen one that takes two hands to remove.

[jonflies]

Tried installing the cap with a much smaller "width" o-ring, but the cap was so loose, I was afraid of it coming off with vibration.

[gmctd]

FYI, mine is tite also, but since it's directly in the fan blast, I'm not inclined to worry about it.
The CDR does function as a closed crankcase system.

[BuffaloGuy]

UH-OH! Mines loose as a goose. I better get that fixed ASAP :eek: