DPF FILTER

[ross bootle]

Hi , i have a d40 2008 model navara. M dpf filter comes on and off , after a burn off its off for a while , i live in sydney and it comes on at random and goes off again of its own accord... Q1... are these things worth getting professionally cleaned? i got a quote for $440 that was me delivering the filter.. Q2.. I have been getting smoke from under the bonnet on the passengers side, has been doing it randomly for ages.. the smoke is a rather white smoke but it can be almost embarrassing sometimes at traffic lights. i cant work out where it comes from other than its around the passenger side area... The DPF light doesnt have to be on when this happens , and theres not other warning lights suggesting any issues.. any ideas anyone ...thanks

 

[Old.Tony]

The DPF should come on normally between every 100 and 300 km of driving depending on the soot level (which is impacted by the throttle, load, speed etc). That's normal.

However that white smoke from under the bonnet is NOT normal. There's obviously a leak somewhere and finding it is important. Things to check:

In the engine bay on the vehicle's left hand guard back near the bonnet hinge is a small module that connects via rubber hoses to two pipes that head down towards the underside of the car. Check the condition of these hoses - if they're perished or missing, this is where your white smoke is coming from and you only need to replace the rubber hoses. This will also help sort out the DPF's operation (the module is a pressure differential sensor for the DPF).

Look at the gold tube that runs around the front of the engine from the EGR valve on the front vehicle's right side of the motor and connects to the exhaust manifold on the vehicle's left side. Check for cracks - you should see black sooty marks around it. Also examine the exhaust/turbocharger interfaces for the same.

Check your coolant level. Is the reservoir at the correct level? Adjust it, drive the vehicle and monitor the coolant. You should check it when the engine is at the same temperature each time and you don't want to see large variations between checks.

 

[ross bootle]

The DPF should come on normally between every 100 and 300 km of driving depending on the soot level (which is impacted by the throttle, load, speed etc). That's normal.

However that white smoke from under the bonnet is NOT normal. There's obviously a leak somewhere and finding it is important. Things to check:

In the engine bay on the vehicle's left hand guard back near the bonnet hinge is a small module that connects via rubber hoses to two pipes that head down towards the underside of the car. Check the condition of these hoses - if they're perished or missing, this is where your white smoke is coming from and you only need to replace the rubber hoses. This will also help sort out the DPF's operation (the module is a pressure differential sensor for the DPF).

Look at the gold tube that runs around the front of the engine from the EGR valve on the front vehicle's right side of the motor and connects to the exhaust manifold on the vehicle's left side. Check for cracks - you should see black sooty marks around it. Also examine the exhaust/turbocharger interfaces for the same.

Check your coolant level. Is the reservoir at the correct level? Adjust it, drive the vehicle and monitor the coolant. You should check it when the engine is at the same temperature each time and you don't want to see large variations between checks.

thanks Tony, ive attempted to pinpoint where exactly the smoke emits from, if you look at the pics , you will see a lot off soot just past the bend of that cooler pipe next to the altinator. Really hard to tell exactly where because the radiator fan blows the smoke away. It usually starts smoking round half an hr of the engine running. No cabin warning lights of any sort come on and the engine doesnt run rough or blow any excessive smoke from the rear. Really hard to tell with the coolant level as theres no markers on the tank but i used a stick and it was about 2 inches of coolant in the tank. I had to replace the fan this week and ive noticed the heater doesnt work yet the A/C is fine. Wondering if these issues are related. I checked hoses ect as you suggested and can see anything unusual. As for the coolant , do i need to do a flush? and how many litre will i require. Would a computer hookup be likely to show any error codes. I posted another post , but just ignore that one , just makes it confusing..thnks in advance

 

[Old.Tony]

It looks like the EGR tube is holed or cracked - it's not exactly the strongest component in the engine. If it is, there are three possible solutions:

1) Replace it. Either from Nissan/eBay or a wreck, it would be highly unusual for a broken EGR tube to cause a vehicle write-off but you run the risk of a 2nd hand one being almost ready to do the same thing.

2) Repair it. Not my first choice, the metal's thin-ish and subject to some decent temperatures (up to around 900C is nearby). Putty would only last a short time and I've never tried brazing it so can't tell you if that would work.

3) Block it. Unfortunately this one is both illegal (if detected) and in later models quite difficult because they included a flow detector in the EGR valve to make sure some EGR was moving through. Your 2008 model won't detect a block, so you could easily remove the EGR tube from the exhaust manifold and replace it with a 3mm mild steel plate.