is it normal that the d40 runs at such pressure.

[kerrie0400]

I travelled 8hrs to buy a Nissan navara stx it was a 2007 6speed manual v6 petrol and had 196000kms. After taking it for a quick test drive like max 10 minutes it was at just under half on the temp gauge. While it was running I tried to under the radiator and I couldn't it had so much pressure I had to turn the motor off n just kept loosen the cap over 5 minutes.

After the cap was off I started it up and the coolant was over flowing out the radiator, I gave it a rev and it covered the entire motor with coolant that's how much pressure was in the system.

Of course the dealer said it had been checked over by there mechanic n was fine.
But I had feeling something wasn't quite right so I didn't buy it. Was I right to leave it or does the navara ment to run that much pressure through the system.

I normally undo the cap to check that the coolant is flowing n see if there are any visable exhaust gases.I know to expect that there will be pressure on the cap when taking it off but I mean the pressure seemed to be alot compared to other cars I have done this with.

What's ur thought on the subject?

 

[Aussie Frontier]

I know mine runs at around the 88 degree mark and the radiator hoses are always fairly taught. Must admit have never run it with the cap off .I would say that running the engine with the cap off would only show the high rate of flow rather than the pressure as without the cap there is no pressure as such. Being a closed system with overflow then I would guess that the radiator cap isnt the highest point so it would spray the coolant out

 

[180degrees]

you can do it but probably not a good idea while its hot, not only cause its gets coolant all over the place but you could be seriously burnt by hot steam from the water that instantly vaporises once it is released from a pressurized system.

 

[Pete22]

You've lost me - I simply don't understand why you would do what you did or the need for ever having to do so. Radiator systems have been closed systems on all vehicles for more than 20 years that I can recall and even in the old days when the vented via a overflow hose to the ground they were still largely a closed system. The radiator cap has a spring that is set to relieve at a certain pressure and vent to the coolant bottle on the driver's side bulkhead in the engine bay. The pressure in the system allow the coolant temperature to be kept to an optimum - as Aussie points out normal running is around 85-88 degrees and when mine is under load, ie towing my camper up steep inclines for protracted period, the temp rises to around 95 degrees. If the system wasn't pressurised the coolant would simply boil and engine cooling compromised.

 

[Tappet]

Dunno why you did that. The coolant will be flowing alright after a 10 minute drive or it would probably be boiling it's guts out.

Wouldn't worry about coolant spewing out in those circumstances.

I would be taking look at what the coolant looked like when cold and what it looks like in the overflow reservoir tank. Does it look sludgy in there?...

Check out the oil to, does it look good or hang off the dipstick like a bit of bitumen? Does it look diluted or smell burnt?...

Look under the oil cap when warmed up, does it look sludgy or lots of condensation, or fumy in there. Listen for rattles from the front of the motor (timing chain)

All the same if you don't feel comfortable buying it- leave it.

 

[LLadnar]

I travelled 8hrs to buy a Nissan navara stx it was a 2007 6speed manual v6 petrol and had 196000kms. After taking it for a quick test drive like max 10 minutes it was at just under half on the temp gauge. While it was running I tried to under the radiator and I couldn't it had so much pressure I had to turn the motor off n just kept loosen the cap over 5 minutes.

After the cap was off I started it up and the coolant was over flowing out the radiator, I gave it a rev and it covered the entire motor with coolant that's how much pressure was in the system.

Of course the dealer said it had been checked over by there mechanic n was fine.
But I had feeling something wasn't quite right so I didn't buy it. Was I right to leave it or does the navara ment to run that much pressure through the system.

I normally undo the cap to check that the coolant is flowing n see if there are any visable exhaust gases.I know to expect that there will be pressure on the cap when taking it off but I mean the pressure seemed to be alot compared to other cars I have done this with.

What's ur thought on the subject?

Ok, I can under stand why you would start a "car" with out it's radiator cap on, as you said checking for exhaust, but not when it's hot. The reason coolant when everywhere when you started it was because all that coolant would have expanded when you released the pressure, most would have come out when loosing the cap but when you start the motor all the coolant getting pumped around comes back to the radiator, with no cap to keep it inside out the top she comes. Normally if there to much coolant in the system when it expand the cap lets it skirt into the header tank, but no cap it ends up in the engine bay. And the reason it was tight was to stop you taking it off when under pressure. They've made the taper on the radiator neck steeper to make it hard to turn. To help stop liability claims.
You'll notice on a lot of car since about 2004-5 there is a sign under the bonnet saying do no touch anything not painted yellow. Your dipsticks, washer bottles, power steer are all yellow. Radiator cap has black cover over it.

 

[Old.Tony]

I have to agree with everyone above.

Coolant systems these days are closed systems, when cold you can check the spring in the cap to see if it feels way too loose but otherwise you'd examine the overflow bottle, drive it for 15 minutes then examine the overflow bottle again. If exhaust gases were escaping into the coolant channels via the head gasket the overflow would fill pretty quickly.

You can't fill them with tap water either. They really do need the coolant - it resists electrical activity and performs better outside the range of water - so it's still a liquid below 0C and above 100C.

Mine sits at 91-92 normally, about 94 when cruising, 96 when climbing a hill. When towing it's around 95-96 until I reach a hill, and then I've had it go up towards 110C - not greatly concerned by that.

The car might be fine, it'll need an engine bay wash and the radiator topped up with coolant but otherwise if nothing else is wrong with it, check as advised above and if you still like it, it's probably fine.

 

[tezza]

Nearly all cars I have experienced will piss coolant out when you take the radiator cap off. It means the system is working and holding pressure, which is what prevents it from overheating. Sounds normal by the sounds of it?

 

[kerrie0400]

The reason why the radiator cap was undone when at operating temp was to see if there was any exhaust gases which can only be seen and tested when the motor is at operating temp. I have done the co2 test on a couple of different cars including my old st-r and on every single one I done it, the coolant did not spill out like this one did, it wasn't a little bit of coolant it was like a volcano which is why I thought there was an issue.

Another reason why was to see if the cooling system/water pump was flowing, I understand the system needs to be pressurised but only when the radiator cap is on, i don't see how that much coolant can come out unless there was an air lock somewhere.

I don't know if all stx do this but it wasn't worth the risk when I need to drive 800kms home.

The dealer would not offer any warranty because of the kms were to high but I have seen other dealers offering warranty with over 200000kms on the clock

I had to replace the head on my old st-r and it cost be close to $1200 to fix it and get it back on the road.

 

[longy509]

it is pressurised so if u take the cap off the pressure has to go somewhere

 

[180degrees]

$1200 is pretty cheap for a new head.

most people pay like $4-7000

 

[kerrie0400]

Yea we saved heaps by installing the new head by ourselfs. My partner is a mechanic which is the reason y we are asking about the cooling system and pressure. In most older cars when the coolant spitz out from the radiator its a sign that the head gasket is blown or a cracked head.

A mate has a 2012 stx its the diesel n his done the same thing with spitting out the coolant so i can only assume that this is normal in nissan navara d40 range.


Has anyone else started there d40 with the cap off to see if coolant spitts out?

 

[LLadnar]

The reason why the radiator cap was undone when at operating temp was to see if there was any exhaust gases which can only be seen and tested when the motor is at operating temp. I have done the co2 test on a couple of different cars including my old st-r and on every single one I done it, the coolant did not spill out like this one did, it wasn't a little bit of coolant it was like a volcano which is why I thought there was an issue.

Another reason why was to see if the cooling system/water pump was flowing, I understand the system needs to be pressurised but only when the radiator cap is on, i don't see how that much coolant can come out unless there was an air lock somewhere.

I under stand why you took the cap off but normally you do it when it's cold then start it up, it don't take long to warm up.
I'm a mechanic and I've seen guys get burnt from coolant and its not pretty.

 

[4 naving]

Yes when I was changing coolant in mine. When you rev it the pump will overwhelm the radiator and it will overflow. The cap on top of the radiator is not the actual pressure cap. the pressure cap is on the overflow bottle.

 

[nathand22]

A mate has a 2012 stx its the diesel n his done the same thing with spitting out the coolant so i can only assume that this is normal in nissan navara d40 range.

Isnt the 2012 STX the V6 diesel??

 

[kerrie0400]

That's good that its normal. the only other issue I have it that there is like a loud whine noise when accelerating.

It doesn't seem to do it when idling and there are no ticking/knock noises. Besides the whining it runs good. I have been reading about the timing chain issues and hope its not the case.

I can get a timing kit out of America but its for the frontier which what I understand is the same motor as the Navara vq40de.

Can any one confirm this before I buy it, the link is below

http://www.ebay.com.au/itm/221231121273?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[Pete22]

That's good that its normal. the only other issue I have it that there is like a loud whine noise when accelerating.

It doesn't seem to do it when idling and there are no ticking/knock noises. Besides the whining it runs good. I have been reading about the timing chain issues and hope its not the case.

I can get a timing kit out of America but its for the frontier which what I understand is the same motor as the Navara vq40de.

Can any one confirm this before I buy it, the link is below

http://www.ebay.com.au/itm/221231121273?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I could be wrong but I understood that the timing chain problem was only with the 2.5 diesel engines. The 6cyl petrol VQ donk didn't suffer from this problem AFAIK.