Friday, Jul 31, 2009 at 19:30
Sounds to me like shes about to grenade, for the same reason all the others before it have.
Look, the advice above about cooling the transmission oil are all valid and they should pursue those avenues because it will help, however given it is the notorious hand grenade model 3 liter Nissan (yeah they explode when the firing pin falls out) I suspect something far more sinister.
Those engines are computer controlled.
They have an oxygen sensor on them that measures the amount of O2 in the burn as each cylinder fires.
The computer uses this info to contol the fuel delivery, only a certain amount of fuel is needed for certain oxygen content - any more fuel and your just over fueling the engine.
Now - O2 levels in the intake air vary depending on ambient air temp, altitude (if you've climbed a mountain range for example) and how moist the air is.
Where theres LESS O2 the engines computer will lean off the fuel supply.
When it does this the temp of the explosion get a LOT hotter.
The problem with the grenade 3 liter is this.
The thin metal tube that leads to the O2 sensor that's then wired to the controlling computer, gets carbon deposits inside the thin metal tube over time and these block it up.
The computer reads this lack of oxygen as high altitude etc - low oxygen and starts leaning the fuel - leading to increased combustion temps.
Eventually the more blocked this little tube gets the more the computer leans the fuel until it gets to a point where the excessive temps burn holes in the top of the alloy piston/s and the grenade goes off & its goodnight Irene for yet another Nissan hand grenade 3 liter bomb.
The silly thing?
1. The O2 sensors are cheap to replace.
2. If you can get to them to remove them the tube can be cleaned out easily with a little wire pipe cleaner, and some alcohol - sensor as good as new and away you go again!
That such a simple small cheap part can totally destroy an entire engine in one big bang at the most inopportune time - is a big worry that Nisan are totally ignoring they won't honor their warranty's for this defect.
The problem is that the computer doesn't KNOW that its being fed false info from the O2 sensor and keeps leaning out the fuel based on wrong info leading to ever increasing combustion temps.
Obviously it isn't the brightest of computers, capable of thinking for itself!
If it were me - I'd get that sucker O2 sensor out and cleaned replaced pronto before she goes bang.
I'd make doubly sure the whole cooling system is 100% (new radiator and
water pump - leave nothing to chance) - then fit oil cooler to the transmission oil line.
Lastly put a EGT probe into the exhaust pipe just post turbo with a gauge inside the cab - to monitor exhaust gas temps and don't run that sucker anywhere over 450c (550 max for brief burst climbing a
hill for example).
If you see 650C then kiss that engine good bye.
While at it - whack a temp sensor into the auto transmission pan and keep an eye on transmission oil temps.
That chart will show you what temps he needs top keep his trans oil down too.
(In the temps chart above at the bottom where it says "above 300 clutches and seals etc melt and burn...and so on - I forgot to convert that 300 to degrees Celsius it's actually 300 Fahrenheit (so the major irreversible damage REALLY starts at 149 Celcius not 300 as it says) Remember that
water boils at 100 C - your radiator under pressure will boil at 120 and another 30 over that the transmissions toast!).
Now you can see the importance of keeping the transmission oil cool here in Australia!
If its been running hot - he needs to get rid of that batch of trans oil.
Just dumping the trans oil from the pan won't cut it, it only gets rid of about half the now oxidized (burnt) transmission oil, everything that's inside the torque converter and oil cooling lines & standard trans oil cooler if fitted will still be old contaminated burnt trans oil.
He needs to disconnect the trans oil line from side of the trans, that goes to the cooler.
Connect a clear plastic hose over the coupler fitting in the side of the box and put the other end into a new 20 liter drum of trans oil.
Put a short clear hose over the disconnected line from the oil cooler and run the other end into a bucket or pan for disposal.
Put the hand brake on as hard as it will go, and chock all 4
wheels.
This is dangerous if you screw it up, so pay attention!
You need to start the vehicle in
park and let it idle, do NOT rev it up, just let it sit there, then with someone sitting with their foot on the brake pedal as
well as the hand brake and chocks drop it into drive and just let it idle.
The oil pump in the trans will start sucking up new clean oil from the drum - you will see this thru the clear line - at the same time the old burnt oil from trans pan, torque converter and valve bodies, oil cooler lines and trans oil cooler
- will pour out of the other short clear plastic pipe into the bucket for disposal - it should be brown and burnt.
Let it keep running until you see NEW CLEAR RED oil coming out the disposal pipe and there's no more old smelly burnt oil - clear red going in and clear red coming out!
Now put back into
park and turn engine off & you have a FULL transmission oil swap/transfusion!
- disconnect plastic hoses and re connect the oil feed line to the transmission.
Now with the same precautions as above (brakes and wheel chocks) - open bonnet, start and put into drive, check trans oil dip stick -= it should be full - if not just top up with extra trans oil down the dip stick tube a little bit at a time until it is reading full when at idle in drive with the brakes on and
wheels chocked, and without touching the blessed accelerator pedal lest anyone gets hurt.!
When you do connect the plastic pipes to trans oil line and nipple on trans - there's two of them , one for oil going to the radiator based oil line cooler and one that returns!l
You can tap into either for a complete transfusion like this, however it is important to get it right - you want the new oil being sucked into the trans thru the nipple and the oil returning line placing old brown burnt oil into the waste bucket not the other way round, i.e NOT to have air suckin from the waste bucket into the trans oil pump and old oil overflowing your new oil 20- liter drum and contaminating that and making a big mess.
Just look at it and think it thru wen you do your connecting of the pipes etc, and it'll make sense.
Obviously if you get it wrong and your watching the clear lines - you'll realise straight away - putting it back into
park should stop the oil pump and you just swap bucket/drum and have another go,
Next.
More cooling for the trans.
You can do as I did and install a
water tank into your vehicle (caravan if you wanted too) and run a hose all the way to the front of the vehicle behind the grill.
Plumb a 12 volt marine deck wash pump into the system with a switch for it on the dash in a convenient spot.
Put some garden mister sprayers (2 is enough) into the hose behind the grill and in front of the radiators, such that when the pump is activated the sprayers will cover the radiators with a fine mist of
water while driving along (I used a plastic 1/2 inch garden reticulation tap in the line to turn it off so you don't siphon drain all your
water when not in use/stopped, and also to regulate the flow & hence mist onto my radiators so I use the minimum amount of
water to get the best coverage of the radiators while moving.
This
water evaporates off the radiators outside, acting like a "
coolgardie safe" which allows them to be better heat sink exchangers for getting rid of the excess engine / transmission heat build up.
Then when driving I watch that EGT gauge and when it;s getting to 450 C climbing a
hill and looks like it;s going to get higher - on goes the
water switch and down comes the engine temps gauge, the exhaust gas temps gauge also drops, and the air con blows colder air, and even the trans oil temps gauge drops.
Next - sub micron bypass engine oil filtering and an after market engine oil cooler fitted. This will help provide longevity for your engine BUT it will also increase the amount of oil in your sump / oil capillary capacity, allowing the after market oil cooler a chance to cool the engine oil!
Engine oil doesn't boil at 100 - 120 C like your radiator
water - instead it serves as a "heat sink" for the excessive temps from your engine that your cooling system is unable to cope with, via the heat exchange system of
water pump and radiator.
If that engine oils getting excessively hot - its very hard to then shed that excessive heat and via convection thru the engine block and auto transmission oil - that heat works its way into the transmission oil as
well.
Its a sinister cycle that builds on itself, you just need everything going for you i.e. ALL fluids being independently cooled - not just the radiator
water being responsible for shedding all the heat from other systems like engine oil and trans oil.
Once one problem (blocked O2 sensor) causing excess heat build up starts working on all the other systems (Engine oil & Trans oil temps) we have damage happening all over the
shop - the engine - the transmission, and a good vehicle becomes a nightmare to try and diagnose!
That's how I tow heavy weight behind an TD automatic 4wd in 40+ AMBIENT OUTSIDE temps, and strong headwinds up steep mountain ranges without problems.
When I did
mine - I pulled the trans pan sump off and put a new filter in there - no point changing all that trans oil, if the old original filter is blocked with contaminated/burnt wet clutch material, and slowing down the rate at which it circulates trans oil thru the trans oil cooler.
I also added an aftermarket alloy deep transmission pan that holds an extra 3 quarts of trans oil over the standard model..more oil takes a lot longer to get hot. It has cast alloy cooling fins in it that also help cool the trans oil while on the move.
Gauges to monitor those temps below - when normal and when HOT
Extra
Water cooling
One 100 liter stainless
water tank for cooling
water
Another 100 liter stainless
tank and marine deck wash pump to pump the
water to the sprinklers (misters) behind the grill.
OK..
Now also eliminate other possible probs,
Dragging brakes on the van or dry wheel bearings on the van will cause the tow vehicle to overheat.
Summary?
1. Clean/replace the O2 sensor pronto
2. New
water Pump
3. New Radiator
4. New Trans Pan filter
5. Deep Trans pan if you are so inclined.
6. After Market Trans Oil Cooler.
7. Complete Trans Oil change.
8. Gauge for EGTs monitoring
9. Gauge for Trans oil temps monitoring
10. Gauge for Turbo Boost monitoring
11. On Board
Water Tank for cooling
water
12. 12 V Deck wash pump switched via the dash
13. Hose and misters plumbed to the grill
14. Engine Oil bypass filtering & after market engine oil cooler
15 Eliminate any dragging brakes, or dry / needing adjustment / replacement wheel bearings on van
You should NOW be ready to go dragging heavy weights around oz with an automatic.
Its a shame manufacturers don't make a product capable of doing that without such substantial modifications before hand isn't it!
Towing with automatics in Oz should be an article or pinned/sticky topic thread - coz I must typed this kind of reply with all the photo links at least 3 or 4 times already in response to similar questions in the past.
Cheers and good luck with it!
AnswerID:
377036
Follow Up By: Muddy doe (SA) - Friday, Jul 31, 2009 at 20:33
Friday, Jul 31, 2009 at 20:33
Geez Flywest,
How many keyboards do you wear out per month???
Cheers
Muddy
FollowupID:
644421
Follow Up By: Davo_60 - Saturday, Aug 01, 2009 at 18:38
Saturday, Aug 01, 2009 at 18:38
Goodness, such a simple fix. Nissan may not make something capable of towing but other manufacturers sure do.
Dave
FollowupID:
644479
Follow Up By: Leroy - Sunday, Aug 02, 2009 at 08:59
Sunday, Aug 02, 2009 at 08:59
I thought overfueling lead to higher egt's not a lean fuel mix like a petrol engine.
Leroy
FollowupID:
644555
Follow Up By: Member - Graham H (QLD) - Sunday, Aug 02, 2009 at 11:25
Sunday, Aug 02, 2009 at 11:25
Jeez would be quicker and easier just to buy a Cruiser and have no problems.
FollowupID:
644583