# Weird problem with oil smell through HVAC!!!



## unclejemima (Sep 1, 2010)

Ok guys (and gals) I've got an odd problem with my xtrail. Its new to me, but has a gong show history with salvage title.

Long story, after lots of time and money, it drives like new. New clutch, tie rods, sway bushings, new interior, etc. Its great. Except that through the HVAC when the car is warm, it smells like oil on exhaust. Its horrible and make the car undriveable as the smell is very bad.

Just to be clear, this is not blue smoke or smell of burning oil through the motor, rather the smell of oil thats on a manifold or exhaust. Its a big difference the odor.

I have no clue where this is coming from. Under the hood and around the car there is NO smell of oil being burned, none. I can shove my head under the hood with the car hot and it smells fine. There is zero smell from the tailpipe.

So what the heck is going on? If I hit the recerc button for the HVAC the smell goes almost copletely away, so its like the smell is being pulled in from wherever the air inlet it for the HVAC. Because of the cars storied past, I'm wondering if someone plumbed something in wrong? I've changed my cabin filter, etc.

Any advice would be appreciated! I'm ready to sell this thing if I can't figure it out!


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## quadraria10 (Jul 6, 2010)

Hi 
Check the thread on the oil cooler gasket replacement. It's probably leaking and dripping on your exhaust. Its at the back of the motor drivers side on the bottom. Its right underneath the firewall and that is why its getting into the cabin air system which is sucking it in with exterior air. Nissan will clean your wallet out to fix it, but if you follow the thread and get the gaskets, you can fix it yourself following the instructions or get your mechanic to do it. Good luck with it.


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## quadraria10 (Jul 6, 2010)

http://www.nissanforums.com/x-trail/198425-oil-cooler-leaking-05-canadian-x.html

here is a link to the thread about the oil cooler leaking.


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## unclejemima (Sep 1, 2010)

Thanks! That sounds exactly what I'm dealing with, and sounds like I'm not the only one.

Just to clarify this oil cooler is for manual trans models as well I assume? I have a manual trans not auto. Just want to make sure before I go into this to far...

Just to make it easier for the next guy who might see this thread, to fix my oil cooler I'm going to order from the stealership:

Large O Ring 21304-JK20A
Small O-Ring 21334-30F00

Thanks!!!


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## quadraria10 (Jul 6, 2010)

Hi Unclejemima,
Pretty sure its identical on both auto and manual versions, after all it is an engine oil cooler and not an auxiliary transmission cooler. From what I can tell it hasn't been that widespread a problem with the X trail, but its not unheard of. I suspect now that all X trails in Canada are pretty much 10 years or older it will show up more often. Especially, for examples where coolant changes were neglected. You may have to drain it anyway to do the repair, so might be an opportunity to change it. Good luck with it.


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## unclejemima (Sep 1, 2010)

Thanks again.

Sorry I'm confused how the coolant condition relates to the oil cooler o-rings?

My understanding is that the coolant would be drained when accessing the oil cooler only because the coolant line was in the way when needing to remove the oil cooler fitting from the block?

It the oil cooler water cooled then? I was thinking it was air cooled rad style.

Sorry noob question.


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## quadraria10 (Jul 6, 2010)

Yup, coolant hoses attach to it. You can see it on the diagram bottom page 1 of the above thread. Chadn also provided the following link
AUSTRALIAN X-TRAIL FORUM :: Engine Mechanical :: fixing an oil cooler leak | Runboard


it provides some detail on the dismantling.


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## unclejemima (Sep 1, 2010)

Thanks. I've ordered the parts. The one of the o-rings was special order.

I'll update on the results when the parts arrive!


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## unclejemima (Sep 1, 2010)

So I essentially ordered part #6 , #4 & #7 ...but what is part #2 ? It says "always replace after dis-assembly" as well. Or am I only worried about 6, 4& 7?

Thanks!


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## quadraria10 (Jul 6, 2010)

Well it does say that, but the part is not available for order. In fact, Cdn dealers do not even have the diagram you have just posted showing that the oil cooler is in fact serviceable. Its probably just a spring valve that you could clean with a degreaser if its sticking, but the issue is most likely that small O ring, and based upon what some have said, tightening the bolt that the no 6 O ring goes through may stop the leaking as a short term fix.


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## unclejemima (Sep 1, 2010)

Problem solved with the oring swap. Day and night difference. Lets see how it holds up.

Thanks guys. Even the stealership was not really sure of this problem, but the nissanforum came through!

Epicness!!!


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## quadraria10 (Jul 6, 2010)

Good stuff. Glad to help.


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## unclejemima (Sep 1, 2010)

Well. The Xtrail has been parked since my last post in 2016...finally got the 4wd fixed with a new (used) rear diff and of course the oil cooler is leaking again causing the awful smell through the hvac system.

I changed the orings with pn, Large O Ring 21304-JK20A, Small O-Ring 21334-30F00 in fall 2016... but we're back to square one leaking. Probably not as much as before, but still leaking none the less.

So... I suppose the next option is to get a entire new oil cooler. Can anyone verify if this is avail from aftermarket or dealer only? I'm being quoted about $800 from the dealer for part only.

I checked rock auto and I only saw the oil cooler lines and oil cooler mount, but not the actual oil cooler.

Advice needed for this broke nissan owner


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## unclejemima (Sep 1, 2010)

Would this work?

Engine Oil Cooler 21300-JA06A,21300-JA05A for Nissan Altima/Sentra 2.5L 07-2012 | eBay


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## unclejemima (Sep 1, 2010)

Here is a photo of the OEM fiche from Nissan...but the 21305S does not come up as a PN I could search on the net?


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## quadraria10 (Jul 6, 2010)

No idea if it fits. The illustration they use makes it seem pretty similar, but the one on ours has a round housing and the one you have linked to has a square one. Also the drawing of the gasket that mates to the block seems slightly different for ours and the one for the Altima or 2008 Rogue. Seems Altimas prior to 2007 did not have this on the earlier qr25de engine in them. That said it might work but it depends on the way it would bolt to the engine.

https://partsouq.com/en/catalog/gen...rKTx1dANzCmECRCpE$&vid=849&cid=8&uid=40545&q=

The above will show you the complete part numbers. 

Are you sure its still your oil cooler leaking and its not a leak somewhere else? Also maybe you could try snugging down the bolts on the cooler anew.


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## quadraria10 (Jul 6, 2010)

Just to follow up, I have been looking at the oil coolers on different Nissans. For most there is no info showing disassembly is possible, and this is true for the xtrail as well, but the service manual does show it coming apart and the components used. And if memory serves the gaskets we have identified as working come from a Pathfinder or Infiniti. Here is a breakdown of a 2003 Pathfinder one.
http://ww2.justanswer.com/uploads/fixurnissan/2011-10-24_120915_03_pathfinder_oil_cooler_o-ring.jpg

The x trail's is pretty similar and the main cooler section is readily available for cheap for diesel x trails on ebay uk. It would take some experimentation but if the problem is a crack or corrosion in that top round housing section, one of those might just fit. The pricing is hard to get your head around for this fairly simple part.
Genuine Nissan is close to $400 whereas they can be found for under 30 for the x trail diesel engine. And its tough to justify the 600 to 800 that dealers are charging for the assembly.

In your shoes I think I would try and find a used one and I would replace the two o rings and probably use some Loctite on the assembly bolts. Good luck. I am curious as to where and how its leaking. Hoping you can share the info when you dig into it a bit more.


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## quadraria10 (Jul 6, 2010)

Last thing, in reading a thread in the Aussie Forum one of the guys doing the write specified he used a gasket sealer in addition to the new large o ring for extra insurance. Other thing to note is this is an issue with a number of Nissan vehicles and very often dealers are saying the whole thing needs replacing and not giving a heads up about replacing the gaskets. Of course this is rather disingenuous on Nissan's part seeing for some post 2007 models they have a service bulletin or recall for the oil cooler and the fix is to replace the 0 rings. I am still trying to get my head around the price of these oil coolers. The part is significantly less complicated than the water pump for example and yet a water pump retails for about 10% of the oil cooler price.


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## unclejemima (Sep 1, 2010)

Thanks quadraria10. Your always so helpful on this forum 

The link you provided for the pathfinder oring shows a different assembly the MT model...just interesting as I have a MT model as well...wonder if its any different on the AT and MT xtrails? The pathfinder had a 3.5v-6 no? Or did it have the same 2.5 as the xtrail?

I did the orings a while back. Did the big and small oring ( Large O Ring pn 21304-JK20A, Small O-Ring pn 21334-30F00) and i'm fairly sure gasket sealer was used to mount the cooler to the block. I didn't do the work myself...it was a mechanic shop down the road. But its been to long for me to go back and complain about it...even though it really hasn't been driven.

I've got a buddy who said he will help me to pull it...but I'm worried that im going to back to square one again unless I get a new one. Its not fun to get at (about a 4-5 hour job if I recall) so if I get a new one then I'd just be done...but $800!?! is crazy.

Funny the altima one is around $100. Everything on the xtrail is comically more expensive. I'm not sure as well if the altima one would work but it sure looks close!

On partsouq.com its coming up as about $450 CAD shipped..not bad, but still a premium for what it really should be. I'm contemplating buying it from there.

A website called autopartsmaster lists it for $260'ish plus shipping (CAD)...but I've never heard of that site before. Not sure I trust it...
https://autopartmaster.com/en/?acti...1b&id_provider=349&price_type=r&price_margin=


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## quadraria10 (Jul 6, 2010)

MMM, so they did not replace the gasket that goes against the engine block, but used gasket sealant? Could be the problem if that is where its leaking. In the Aussie forum one guy used gasket sealer in addition to the O rings to ensure a full seal. There are also tips and instructions for cutting down on the time required. Sadly ours is not in the same position as that in the 3.5 that is behind the oil filter.
Like I said I have no clue if the one for 2007 and on Altimas, Sentras, Rogues, and T31 X trails would actually fit. Cheapest way to figure it out would be to order the gaskets that go against the engine block for both Xtrail and Rogue and compare them. If they mate up you can probably use the new design. But do remember their have been many more reported problems and even a recall for the newer oil cooler design. Problems with the rubber seals in those as well...
Seriously in your shoes I would find a used one or try and fix mine anew. The price for a new one is simply crazy considering the actual complexity of the part. Seriously how can the oil cooler be more expensive than a new alternator from the dealer???


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## quadraria10 (Jul 6, 2010)

I found pics of both and their respective gaskets and they are not the same, so the 2007-on versions won't work.


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## unclejemima (Sep 1, 2010)

quadraria10 said:


> I found pics of both and their respective gaskets and they are not the same, so the 2007-on versions won't work.


Hey thanks for checking anyhow. Damn Nissan. Wonder why they would go out of their way to make the oil cooler just so slightly different. Buggers.

Oh well. I'm going to pull and try to fix what I've got. Trying to find a used one but no luck yet. Let me know if you hear of any.

Thanks for you help


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## quadraria10 (Jul 6, 2010)

https://www.drive2.ru/l/5063455/

The link above is for a Nissan Primera that uses the same oil cooler as ours. Has good pics of the different parts. I have to suspect this is a very rare occurrence because there is no aftermarket oil cooler to be found. I can find the aluminum circle part available for diesels, but nothing for the qr20 or qr25 from 01-06. Ours is not quite as thick and has a different backing plate. More like what is found on the Pathfinder, but the hose mountings are different. 

If you can find one at a U pull place, its not the easiest thing to get at, and then you would have to wonder as to its condition as the only reason these fail as far as I can see, is because one of the gaskets fails. My guess from what you described is that gasket that goes against the block was not replaced, and it could be leaking from there. Is there any way for you to look at it or take some pics? Maybe you could get the guy who fixed it the first time to give it a look see as to what is going on and perhaps he will give you a break on fixing it anew.

Here is a link to the aussie forum thread on this subject. Might provide some extra info for you.

http://baustralianxtrail.runboard.com/t130293


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