V6 Crank Shaft Oil Seal

[g8dhe]

Also check out there's no blockage of the engine breather system - often the cause of seals leaking - change the seals without checking the breather and the problem will raise it's ugly head again............................

Does the Workshop manual for the V6 indicate where these are ?

[dandywarhol]

Don't know but lushprojects no. 13-890 is the positive crankcase ventilation valve and associated bits. The PCV is often a renewable service part
http://www.lushprojects.com/bongopartsm ... o=.html#28

[g8dhe]

Ahha thanks Alan, I'll give them a checkout I think, presumably one should feel an air flow out of them if disconnected ?

[dandywarhol]

I guess you should - depends how the system is operated. The downward movement of the pistons cause a pressure in the crankcase which has to go somewhere - in the good ol' days they just vented out to atmosphere - big no no these days!

The fumes have to go somewhere so they're directed back into the air intake system but only under certain conditions, usually controlled by a vacuum diaphragm. If the system is choked (often the case, especially in low mileage journeys, like Japanese cities, the fumes try to escape past any available outlet - like seals!

http://en.wikipedia.org/wiki/PCV_valve

[g8dhe]

Thanks interesting reading, it sounds like I won't actually feel a lot of pressure, as its more dependent on being sucked out by the lower pressure in the inlet manifold http://www.lushprojects.com/bongopartsm ... o=.html#10 down the pipe 13-895B.
I'm concerned as the hot/burn't oil smell has increased this year on the V6, so I think it might be worth checking myself and discussing with the garage we use in case its that rather than the Cam seals actually having given up!

[Ron Miel]

Indeed, very interesting reading Geoff - and Alan.

After a lifetime with dealer-serviced company cars, and new/newish, also dealer-serviced, self-owned cars, the Bongo and this great forum have begun to teach me all the things I used to take for granted - it's never too late too learn. Until now though, I would have read PCV as just a dyslexic plastic.

My recent experience might be relevant here. After prolonged fuel over-dosing of Flashlube in our LPG-converted V6, and having failed to find time yet to fit an electronic dosing kit I bought months ago, I suspected that it had gummed up my lambda sensor, if not also the cat converter.

After carefully reducing and monitoring manually controlled Flashlube dosing, until it is now running a bit below the recommended rate, I then ran a bottle of this http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... SA:GB:1123 through, in a quarter tank of unleaded as recommended. We then set off on a 1350 miles trip (mucho mileage done rushing around a wide area, looking at 40+ houses, part of a possible re-location idea), up hill and down dale in the Brecon Beacons, Somerset and Devon.

Don't know yet if there's any hoped for mpg improvement, as I haven't yet emptied out on LPG - I always test from empty to empty, to remove the nominal 80%-full tank shut off level variations you get between LPG pumps. However, I can definitely confirm that our V6 has never run more sweetly, and that the hot/burnt oil experience*, which like yours had been getting worse on hill climb/full throttle, is now almost totally absent. Have another long trip starting in a week or so, and having read this am now going to splash out on another bottle beforehand, to see if that might clear it completely. It's possible that it's begun to free up a gummed up PCV valve isn't it, although that might still take a bit more treatment for completion.

*(but no oil leak, or replenishment needed)

Might be worth a try on yours? Anyway, will report back on here, once I've done the further trip.

Cheers

David

[Ron Miel]

BTW, I have previously had Flashlube running at a low dose rate, and that alone did not produce the improvements just seen.

[apole]

Hi there,

Following on from the advice earlier in this post the idea tha the PCV valve could be faulty and cause an increase in pressure inside the engine is a very good point. I know of this due to the same issue in another car I have. So, as my car does show signs of older oil mist around the area of the PCV I went ahead and replaced mine today. Very simple task and the spring clip securing the pipe can be moved by hand so no tools required.

Now, if I'd thought about things beforehand and not been an old fool, I would have thought to test the old one first, as from what I can see the PCV is a one way valve, in this case letting pressure out but not air back in. Cleaning mine up it seems to be working anyway, but I'm leaving the new one on nonetheless.

I should also have taken a picture, but if anyone is interested it's a small black plastic tube under the drivers seat, at the rear upward facing end of the rocker cover, just behind the last spark plug. It has a small diameter rubber hose that takes off around the back of the engine. Simply loosen the clip by squeezing the metal lugs together, move the clip back up the pipe then the hose can be pulled off the PCV. The PCV itself just pulls out of a rubber grommet.

The part is readily available at a mazda garage and is still used on other cars such as the 1.8 MX5 and loads of other jap cars like Kia's so not hard to source.

[g8dhe]

Ah good to hear. As soon as a couple of other jobs are out the way then I think it might be worth a quick oggle at the valve and see if mine appears OK.

[cheffy34]

A good old suck and blow will tell if it works

[wishmaster]

Thanks interesting reading, it sounds like I won't actually feel a lot of pressure, as its more dependent on being sucked out by the lower pressure in the inlet manifold http://www.lushprojects.com/bongopartsm ... o=.html#10 down the pipe 13-895B.
I'm concerned as the hot/burn't oil smell has increased this year on the V6, so I think it might be worth checking myself and discussing with the garage we use in case its that rather than the Cam seals actually having given up!

I too have the dreaded hot/burnt oil smell ( not to bad i must say), i as many others think its was the 'seals' and ideally would like to eliminate this wiff completly

Indeed, very interesting reading Geoff - and Alan.

After a lifetime with dealer-serviced company cars, and new/newish, also dealer-serviced, self-owned cars, the Bongo and this great forum have begun to teach me all the things I used to take for granted - it's never too late too learn. Until now though, I would have read PCV as just a dyslexic plastic.

My recent experience might be relevant here. After prolonged fuel over-dosing of Flashlube in our LPG-converted V6, and having failed to find time yet to fit an electronic dosing kit I bought months ago, I suspected that it had gummed up my lambda sensor, if not also the cat converter.

After carefully reducing and monitoring manually controlled Flashlube dosing, until it is now running a bit below the recommended rate, I then ran a bottle of this http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... SA:GB:1123 through, in a quarter tank of unleaded as recommended. We then set off on a 1350 miles trip (mucho mileage done rushing around a wide area, looking at 40+ houses, part of a possible re-location idea), up hill and down dale in the Brecon Beacons, Somerset and Devon.

Don't know yet if there's any hoped for mpg improvement, as I haven't yet emptied out on LPG - I always test from empty to empty, to remove the nominal 80%-full tank shut off level variations you get between LPG pumps. However, I can definitely confirm that our V6 has never run more sweetly, and that the hot/burnt oil experience*, which like yours had been getting worse on hill climb/full throttle, is now almost totally absent. Have another long trip starting in a week or so, and having read this am now going to splash out on another bottle beforehand, to see if that might clear it completely. It's possible that it's begun to free up a gummed up PCV valve isn't it, although that might still take a bit more treatment for completion.

*(but no oil leak, or replenishment needed)

Might be worth a try on yours? Anyway, will report back on here, once I've done the further trip.

Cheers

David

David, after putting Cataclean in the tank how many miles did you cover using 'Petrol' to thoroughly clean through the system Im tempted to try this as im also on flashlube and got the 'smell'. My V6 is purring at the moment , so no problems with the running of the vehicle

Izzy

[Ron Miel]

Hi Izzy

Apologies for delay - still in mid-trip. Don't know the mileage run on Cataclean/unleaded but did run a second bottle through the system as above, mixed into a quarter tank of unleaded as previously. The Cataclean instructions say you can then completely fill up on petrol after only 10-15 miles in that mode but I'm afraid I almost emptied the petrol tank each time before filling up again (to half a tank) - i.e., each bottle went completely through at the higher concentration.

Can't guarantee it was Cataclean which did the trick, of course, and we're in Norfolk at present, so precious few decent hill climbs, but after long high cruising speed motorway stints (when I would previously have had hot engine pong in the cab), there's now only a bit of front heater mustiness - better clean the matrix this winter

Also, mpg has increased back to normal - but was that Cataclean's effect on the lambda sensor, or did I have some of the the oily LPG reported in another topic to have been in circulation? Of course, one can easily change a lambda sensor and a PCV valve, as Andy Pole (apole) has done recently, but I opted to give Cataclean a whirl at comprehensive engine clean out instead - and it's probably worked.

One thing is sure, if PCV valves do commonly gum up, we V6 owners need to regularly check for that, and sort it out one way or t'other, to reduce oil seal problems.

Cheers

David

[dillinger]

Hi everyone,

Sorry for resurrecting such an old thread, I know it's drifted away from the initial post but I really need your help!! My V6 Bongo has been off the road for a few weeks now after developing a pretty bad oil leak. The garage it's currently lodging in have told me what they need to fix it but I'm struggling to find one of the parts...

Does anybody know where I can get a Front Crankshaft Oil Seal for the 2.5 V6 Bongo ???

I've tried Allans, Bongobits and some bloke on eBay but no luck so far. Bongobits do stock a front camshaft oil seal for a 2.5 diesel (http://www.bongobits.com/Main.asp?PageN ... roduct=250), but I haven't been able to get in touch with them to see if they stock the V6 equivalent. I've been able to find all sorts of other o/s, n/s, cam seals etc but not sure if they're the same thing....please help a mechanical dunce!

Absolutely brilliant forum btw and thanks in advance for any replies!!

D

[Ian]

Does anybody know where I can get a Front Crankshaft Oil Seal for the 2.5 V6 Bongo ???

D, the part number is JE1510602A. Armed with that you should be able to obtain one within a few days from any good Mazda dealership, but if you have difficulties we have one available via the Bongo Shop. We refer to it as a "Crank Oil Pump Seal" and you can order it online at http://www.igmaynard.co.uk/bongo/merchandise5.htm#Misc or by phone.

[dillinger]

Thanks so much for the reply Ian! I had noticed that part in the shop, but wasn't sure if it was the same bit. Will give Bongo Towers a call in a sec...