gq bonnet vents

Thanks Ian for the response and having heard somewhere else that by raising the bonnet by 15mm via spacers can help.But in suggesting it to the Mrs that the bonnet near the windscreen will be up by 15mm she said that bonnet vents will look nicer BUT I will try the spacer alternative just to prove a point.I will post the results as soon as we have them which might be later this year as we in Victoria are experiencing rather chilly days and I am sad to say the Hot days are gone.

regards andy

I have to agree with Ian, regarding the tendancy for this motor to run hot under load but I will disagree that they can't be blown up. The Brother in law is testament to this after just getting his GQ back this week due a completely thourough blown 4.2 diesel engine. Solution was to put another one in it was that bad. I don't know the full reasons behind the failure (if you could call it a failure with 400+ thou km on the clock). Ian is right that they are a DAMN TOUGH ENGINE THOUGH.
Even the GU that I have runs hot but I have still got a hard earned 260 thou on mine already without too much drama.

Cheers Trevor.

I have to agree with them being tough. We used to run them where i work and they were unstoppable! I drove 1 from the 18 level to the surface(read 15 min on redline) with the gauge on the stoppers without a problem. Once up top the motor cooled down and everything was as good as gold!
You gotta love company cars!!

Cheers Gerard

The plug is below the exhaust manifold.

Andy,
I think 93Maverick was referring to the coolant needing to be flushed out using the plug under the exhaust manifold.

An unconfirmed story I have heard about the 4.2 Nissan motor is that a number of them have been produced without completely removing the casting sand from the water galleries. This, it is said, causes the coolant to not circulate properly.

I have tried many things to stop my GU from over-warming.........(note, I refuse to refer to it as "overheating" as that implies that the motor has ceased to operate at some stage..........mine has never let me down). I have spent a lot of time on this forum typing out the long list of what i have tried etc.

Basically, the 1st thing you need to know is that just because the temp gauge needle nudges up towards the right side of the gauge, it doesn't mean you have a problem...........at least not until the needle gets into the small 'extreme' section (provided your gauge is doing what it was intended to do). I didn't trust the gauge and wanted to know what the rael temp is, so I fitted a VDO gauge in the top radiator hose. This new gauge shows the temp properly. It is amazing that the OE gauge will sit on it's "normal" position (just below half way) from a coolant temp of from about 55oC to 105oC. Once the coolant reaches 105oC, the Nissan gauge's needle starts to rise quite quickly..........reaching almost into the 'extreme' section at around 120oC.

Now, as for the bonnet vent idea.........there is a bloke in Sydney known as "DB" (Dave Bradley). He used to be a tour guide for Great Divide Tours (the same mob that "Wayne NSW" works for). He used to own a GQ with a Safari turbo/intercooled 4.2L motor which used to get warm too. He had a bonnet scoop from a 3L Patrol fitted into his bonnet.......BACKWARDS (as a vent). It was located centrally on the bonnet, just behind the radiator. He reckoned it helped his GQ a lot. (that GQ was featured in an issue of 4WD Monthly several years ago, as was his next vehicle, a GU the same as mine).

I've put in a huge PWR aluminium radiator, a 3L Patrol's bonnet scoop above the turbo, moved my Lightforce 240's to the top rail of the bullbar, installed a 14" Davies Craig fan in front of the radiator to assist blow air through, put in a new genuine fan hub, tried a couple of different brands of coolant (Red Line was one and Amsoil's is what I'm currently using).

Mine only climbs up to around 105oC (with Nissan gauge still on 'normal') or sometimes a bit higher, on fairly hot days (mid 30's and above) and normally only when I'm towing the camper trailer at highway speeds. At New Year the temp on NY's eve after work was about 43oC and we were off to the Murray River. I didn't spare the ponies.....travelled @ 100k/h for about 3 hours with air-con on and with temp gauge sitting on or around the 115oC mark. I wanted to see what would happen. The old girl just took it in her stride.....never missed a beat and never slowed down or showed any ill-effects.

I know it's easy to say....but try not to worry about it. I wish I hadn't cut a hole in my bonnet and fitted the scoop, or spent $1100- on the PWR radiator etc etc....waste of money I think.

Cheers nad good luck

Roachie

yeah i think there is an ADR reg disallowing rear facing bonnet scoops etc for just that purpose.

Raising rear of bonnet could end up with same result.

Rev

Hi Just looking through the many posts re over heating and all the work every body has put in to solving it. All seem to work on the water side cooling system, but as some one else mentioned in another thred the water/radiator only dose 1/2 the cooling in any engine, Oil has 2 major jobs in any engine lubrication and cooling.

Just wondering has anybody tried adding a oil cooler ? or direct monited the actual oil temp ?