What's causing o-ring leaks on my '04 Frontier?

[Q451990]

Any chance you have the removed components and a pair of calipers to make some comparative measurements?

Sadly, I tossed the old parts after last summer's work.

[Cusser]

Cusser, my Frontier is also a 2.4L with about 110K miles on it. I'm in central South Carolina, so it's hot - but not AZ hot.

It looks like your fan clutches have failed on both of yours, and I'm curious how you diagnosed them? I've spent more time than I'd like to admit watching youtube videos and searching forums to find out. The Nissan service manual only talk about wobble or play in the bearings. I've checked mine, and it can't be stopped with a rolled up magazine - and the resistance changes depending on if it's hot or cold (based on how many blades I can spin it by hand) but I still can't get a definite answer on how to test one. The fan shroud is fine, but there has been some breakdown in the foam that surrounds the condenser. I'll have to work on that.

I noticed the fan clutch on my 1998 2.4 liter Nissan Frontier was bad when I went to remove it to replace a leaking water pump; the fan was pretty much stuck at ambient temperature, had no other symptoms.

Last year, I tested both my 1998 and 2004 Frontier fan clutches by CAREFULLY using a thin section of newspaper, and CAREFULLY sticking the end into the running fan when the engine was hot, to see if that would stop the fan. BE CAREFUL, or they'll call you "Lefty".


As to chinese-made parts, when I replaced the high pressure line on that 1998 Frontier, the replacement part was 5.5mm longer than the (discontinued) factory line. The distributor of such part was in Texas, and reviews of that part were good, saying easy fit, and told me the typical "no one else has ever had this issue before" line. I cut the line fitting 5.5mm shorter and that worked; fortunately the groove for the O-ring was in the correct place, so I didn't need to have a part custom-made. You think I make up such scenario?????? Replacement line sure seems different to me !!!

[Tim]

It looks to me like they need a captured o-ring.

[bohica2xo]

Yeah, that is the pic of the sloppy groove. A ptfe backup ring contains the O ring in the groove.

[Tim]

Yeah, that is the pic of the sloppy groove. A ptfe backup ring contains the O ring in the groove.

Trim the depth and a captured o-ring. Not sure why so many after-market hoses are off. But think most are from a specific source. Not blanket imports.

Never used the setup like that, work well?

[bohica2xo]

Tim:

They are pretty common on high pressure hydraulics. They work well. Most standard sizes:

https://www.sealanddesign.com/wp-conten ... s28774.pdf

Sometimes on import parts it looks like they used the wider groove spec. - that tool is more robust and lasts longer, but you need the backup ring.

What are you calling a captive O ring? have an image?

[Tim]

Captured.

Same size o-ring but thicker. Like a #12 o-ring and a #12 captured that goes in the back of an A6 compressor. They don't have all sizes this way, mainly the basic 6, 8, 10, 12 and metric.

[bohica2xo]

same principle, stuff the groove tighter. The teflon split ring helps with housing clearance, keeps the O ring from extruding past the edge of the groove at high pressure.

I have seen small diameter O rings stretched in to grooves below / behind the "correct" O ring to improve tension too. Sort of tucked under the radius of the larger O ring.

[Q451990]

Interesting. I guess the back-up rings are my next thing to try if it starts leaking again. My old factory hose shouldn't have had wide grooves though. I wonder if the cheap o-rings could be made to meet an inside and outside diameter specification while being sort of oval so that they aren't as thick?

[tony1963]

I noticed about ten years ago that aftermarket parts were becoming less "original" in their designs. I guess you could say that they were cutting corners on the design to get the production and sales started.

I once used a supplier for AC parts that the prices seemed right until we received an evaporator core for a GM vehicle and the threads on the suction line fitting were not machined properly. Yes, we go the part to fit, but we decided that the extra time to "make it work" was not worth the discount. So, I discontinued using that supplier and bought parts from another source.

I will not disclose the origin of the bad parts.