burning smell occasionally after driving my v6

[ma woo]

Can anyone help with a diagnosis on an intermittent burning sort of smell that I have been getting sometimes after driving my V6? It doesn't have to be very far. Just comes and goes. Can't see anything leaking out though.

[cheffy34]

Prob burning oil most of us have had some sort of issue with it mine was a simple fix others have not been so lucky

Dar

[apole]

Hi there,

Agree with Cheffy here, I had this, people told me it was probably oil leaking from the camshaft oil seals, couldn't see anything, no oil use etc so wasn't sure.

Then one day I had a good rummage around and it was true.

What happens is there are 4 camshafts, at the top front of the engine are the oil seals. These are covered by the toothed wheels for the camshaft and plastic covers. Oil seeps out of them, drips slowly down the engine behind the covers, and then hits the sump lip at the bottom. The sump is at an angle so the oil neatly runs around downhill and then at the lowest point drips off where mazda very conveniently placed the exhaust so something nice and hot to hit. Only takes a tiny amount to make a smell.

Best way to tell is to get under the car and run a clean white kitchen towel around the rim of the sump, if it's oily that's your problem.

Failing that, check that nothing else is leaking, e.g. your power steering fluid bottle, or say oil coming out of the cam cover etc. Under the bonnet at the front on teh side of the big black plastic air scoop there maybe a lever. This is used for air coming into the car ventilation system, lever one way draws cold air in, the other warm air from around the engine. If it's on the warm setting then any smell from the engine is drawn into the car. You may not have this as not all bongo's do.

Pic of oil stain on exhaust:



Picture of oil leak when the front of the engine was dismantled to change the seals:



The leaking seal is the top left hand one and the messy oil bit at the bottom is the camshaft tensioner.

If it turns out to be this and you need help with a good garage and sourcing the parts, drop me a line.

Regards

Andy

P.S. Don't forget to put your location in your profile.

[ma woo]

Thanks for that detailed response! I had better get on and investigate! I will take it to my local garage man and get it up on the ramps. And if there are parts needed I will come back to you - thanks very much indeed.

[ma woo]

Oh and I just noticed that I have become a junior bongonaut - still feel like an apprentice tho!! No - complete b.....y novice to be honest, !

[ma woo]

One last question - how do you ammend your profile to include location?

[apole]

Hi,

To put in your location select "user control panel" top right of screen (when logged in), then profile from the list on the LHS.

If it's the seals then make sure you have an experienced fitter work on your car, it's not for the faint hearted as lots has to come off to get at the seals.

Good luck.

Andy

[New Forest Terrier]

The seals are the worst case scenario. My V6 whiffs in cold weather and has done both winters I have had it.

It uses no oil, never had to top it up, and the cam seals look fine. Checked out on last service. The "cure" is to go round the engine cover clips with the rubber tent mallet and knock them back to shape so that they seal tight. They work loose over time due to the covers being raised.

I don't have the air intake lever, so putting the heater controls to recirc at start up stops fumes being sucked in while I reverse up the drive. For some reason, the whiff is stronger in reverse. Just due to reversing uphill through the exhaust fumes I guess.

[New Forest Terrier]

The seals are the worst case scenario. My V6 whiffs in cold weather and has done both winters I have had it.

It uses no oil, never had to top it up, and the cam seals look fine. Checked out on last service. The "cure" is to go round the engine cover clips with the rubber tent mallet and knock them back to shape so that they seal tight. They work loose over time due to the covers being raised.

I don't have the air intake lever, so putting the heater controls to recirc at start up stops fumes being sucked in while I reverse up the drive. For some reason, the whiff is stronger in reverse. Just due to reversing uphill through the exhaust fumes I guess.

[g8dhe]

to recirc at start up stops fumes being sucked in while I reverse up the drive. For some reason, the whiff is stronger in reverse.

Yup we find this as well, also at certain locations around town when we stop for lights etc. I've put it down to the fact that when your moving any smell is blown backwards, but when you stop/reverse if there is any breeze blowing the fumes forwards underneath the car that's when they get sucked into the air intake.
I plan at the next service, due soon, that I ask our garage to give it a clean and see if they can spot where the oil is coming from, but I suspect the cam seals but there is hardly any oil being used so I think it might be a little while before the cam seals are replaced if that is the problem.

[apole]

I haven't noticed any smell when I reverse.

Regarding the seals, I'd leave it until it gets to a point that you can't stand the smell. The parts are not too expensive, you need seals, new cambelt as minimum and I'd suggest new thermostat, cooling system flush, and new water pump too whilst it's all apart then you know that is all taken care of for a few years, rather than leave it and have to rip it all apart again !!

In my case there was no oil contamination on the cambelt so it's unlikely leaving it will have any untoward effects other than the smell....

Factor around 10-12 hours labour for the whole job and make sure the garage has experience as it's very intense work.

Any help needed on parts/suppliers/garages that know what they need to do please feel free to contact me.

Don't forget to check the obvious things first though before embarking on a big job like this.

[alans00ty5]

when i park up after a drive i get a rubbery sort of smell but not every time, and i dont get any internal smells.but every thing seems to be ok.

[manners]

For the past month after a drive Ive had the burning smell again only had all the seals done last year so no major leaks nothing on the exhaust just a very small leak on rocker cover, but while crawling underneath i noticed the cloth liner on the under tray was blowing up and touching the exhaust so stuck it back down and no more smells This could account for a few peeps only noticing it in reverse as it will blow up if it has come loose.

[mikeonb4c]

Seems to me the mid engine arrangement on the Bongo makes it a good candidate for any slight smell rising with hot air and wanting to exit from the upside down bowl that holds it. So engine covers gasket seal (and thus tight clips) has to be an issue. Next is preventing smells from being created (as per suggestions above). Next is flushing (scavenging) air out of the upside down bowl. I have a scavenger fan over-ride switch. Officially intended to prevent excess heat into the cabin on hot days, its a good whiff flusher too. I have a v. minor leak from a diesel pump O ring (for 3+ years now). Cheap solution was simply to place a clean rag underneath it on the engine tray to catch any drips and change the rag every few months. Any whiff from there if I'm stationary in traffic can be removed with scavenger fan. Works a treat.

Moral of the story - look for the cheap workarounds before going for the big spend

[New Forest Terrier]

Totally agree with Mike on this one, investigate the small problems first. Cam seals on a V6 seem to be the equivalent of heads and gaskets on diesels, What everybody dreads, but not always the case.

My whiff is definitely relate to a cold start. Warm morning today, no sign of a problem. I am not sure how the cold start works on a petrol. Absolutely no winter pack on mine to be the cause. I am wondering if the EGR could be involved, but again not techie enough to figure it out.

As it goes away at the first sign of Spring and has not got any worse over the two years, unless proved otherwise, it just comes out as part of a quirky car.