Submitted: Wednesday, Feb 04, 2004 at 15:47
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G'day Cokeaddict,
I've just been going through the archives and found your Post # 9502 when you were asking about oil coolers but also mentioned about the plastic bit of stuff bolted to the chassis under the radiator. I'm like you (but I've got a GU 4.2 t/d) and have some "overwarming issues" (as opposed to "overheating problems"!!!). One of the things I tried was removing that plastic plate too. Wrong thing to do. I thought it would allow more air to get up into the engine bay, but have discussed with an engineer. The whole purpose of the plate is to act as an "air-ram". It's purpose is to create a vaccuum under the motor which will draw out the hot air from the engine bay. Although it is not practical to do so in a 4x4, he suggested the fitting of a bigger/longer plate under there would improve things too. I went the other way and put a bonnet scoop above the turbo, figuring that if I can get some more air flowing in from the top and have the air ram sucking it out the bottom, that should improve things too.
I noticed there was the usual amount of Toyota v Nissan dribble in that Post as well and while I don't even take any notice of that sort of stuff, there was something that one of the pro-tojo posters said which made sense.....If the temp is going up it means that the cooling system isn't coping with the load it is being asked to manage. I'm seriously considering shelling out the $1125- for a new PWR radiator as I tend to agree (reluctantly) with the idea that Mr Nissan does sometimes try to cut corners to save a few bucks. The size of the radiator on my GU is too bloody thin, being 2 cores of around 16mm each. When I have a look at a mates old 60 series, it's much thicker, but no where near as wide. His fan drags air from a larger proportion of the radiator than the Nissan's fan ever can hope to. The new PWR radiator can't address that issue, but it will provide a 2 core radiator which is 57mm thick. All I've got to do now is convince the Minister for Finance & Good Times.
How is your GQ going now? Did you end up finding a place to mount the oil cooler? I agree with Truckster, if I was putting on an intercooler on, I'd be looking at a top mount jobbie (but then again, I'm half way there because I've already got the bonnet scoop in place, but probably in the wrong bloody place knowling my luck!!).
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Reply By: Member - Raymond - Wednesday, Feb 04, 2004 at 16:14

Wednesday, Feb 04, 2004 at 16:14
Hi Roachie
I am intrigued, I own a GU 2002TD and as you can see from the photo it is heavily laden all the time weighing in at 3.75 tonnes and we use it to tour with and also offroad and the temperature gauge never moves off 40% up the dial and that included doing the Kimberley's with airconditioning on and it has reasonable large driving lights in front of the radiator. We had vehicles in our 4WD club with overheating problems and they flushed the radiators to no avail. After removing the radiators and cleaning the mud, insects and leaves mainly from the bottom 30% of the radiator the problem went away. May be worth the check, blowing or washing out with the radiator still in the vehicle did not help as this area is fairly hard to get at.
Raywanderin' in retirement. victor 2010
AnswerID: 45437

Follow Up By: Roachie - Wednesday, Feb 04, 2004 at 16:47

Wednesday, Feb 04, 2004 at 16:47
G'day Ray,
Yes, there seems to be alot of blokes with the same problem I have. Last year, I loosened off the 2 brackets on top of the radiator and leant it back towards the motor as far as it would go (only a inch or 2). There was a heap of leaves and other cr*p down there which I vaccuumed out as much as I could. Then took it to a local radiator place. They removed and cleaned it out about July last year, reckoned it was about 20% blocked. We did a trip to Mungo NP in south western NSW (from the York Peninsula, SA) on the October long weekend and went through a lot of mud. There is still a lot of the dried-on stuff up underneath despite a few thorough washes I'm wondering now whether I copped a bit of mud onto the radiator during that trip?? I had it largely all pulled apart last weekend too, to put in a new genuine viscous fan hub, but didn't take the radiator right out...should have eh? Also put new top and bottom hoses on too as they were the originals that were on it (115,000klm over 3.5 years or so) and I've read on a previous post about a bloke who said he'd noticed the bottom hose was sucked in on itself when it got too hot.
Glad to hear that your rig is going well. 3.75t is quite some load; you nearly need to add a lazy axle!!
FollowupID: 307542

Follow Up By: Truckster (Vic) - Thursday, Feb 05, 2004 at 21:28

Thursday, Feb 05, 2004 at 21:28
Hosing out the radiator of mud only gets about 40% of the surface, the only way to get all the mud out is to remove the radiator.
FollowupID: 307684

Reply By: Peter Guy - Wednesday, Feb 04, 2004 at 16:43

Wednesday, Feb 04, 2004 at 16:43
Yes I am surprised too, as my 98 ST GU TD Patrol @190,000ks still runs in all conditions just under half way on the temp gauge in 44C with air on and towing an off road camper trailer.
The only exception was on a recent trip over East at Lamington NP ,Jenolan Caves and Kosiosco NP where it ran above the half way mark due to the bloody steep hills/mountains, high revs-low gear, hot weather and the trailer with a heavy load. I'm thinking the tempory shade cloth I tied on the radiator grill to stop insects gumming up the radiator was not a good idea as it restricted the air flow. The radiator never boiled and once on the top of the hill and on the down hill the temp gauge always dropped back to normal very quickly.
I'm curious as to the life expectancy of these new aluminum radiator cores.
Any one out there know??
AnswerID: 45442

Follow Up By: Roachie - Wednesday, Feb 04, 2004 at 17:05

Wednesday, Feb 04, 2004 at 17:05
Sounds like yours is doing pretty well too, although it still got a bit warm when working hard in hot conditions, which is totally understandable.
The radiators in Patrols (and probably other late model 4x4's too) are alloy anyway, but with crimped-on plastic tanks. IMHO, the alloy radiators should be as good as (or hopefully better than) the OE items as far as expected life expectancy is concerned......they'd bloody-well want to be for $1100-!! The alloy is supposed to have better heat disipation qualities than plastic or copper.
I'm still working up the courage to phone PWR and place an order. I just wish I knew whether the temp gauge going above half way (not into the "danger" at the extreme right side) is doing any long-term damage to the motor. Nissan reckons that anywhere before the "danger" zone is considered normal; but if so, why does it shut off the air-con??

FollowupID: 307544

Follow Up By: Peter Guy - Wednesday, Feb 04, 2004 at 18:26

Wednesday, Feb 04, 2004 at 18:26
Roachie it seems odd that your air conditioner shut off when your temp gauge went up.This normally only happens when the air con gas pressure is too low.
My Nissan gauge went near the "danger" area but when I checked under the bonnet there was no sign that it was running any where near boiling.
My understanding is the diesals run cooler than petrol engines and there is a tolerance in the diesals for greater tempeture variations.
You have to be careful that the operating tempeture is at the desired level for optimum performance- a too cold engine and a too hot engine can create problems as well!
The Nissan temp gauge doesn't show how close to the boiling point you are as they are just a guide.But is is unnerving when the temp is above the point you are used to seeing it sit at.
My experience with overheating cars is that once they boil they will require the cores to be properly flushed by removing the top and bottom tanks as the cores will be badly blocked. Once the temp gauge starts to climb it doesn't stop and boils.
So I would think that if the temp gauge climbs and then returns to normal then the radiator / thermastat is doing it's job.
The water temp would rise and in turn the thermastat would open further to let more water through and then the temp should fall. So the temp gauge will increse before it will drop.
FollowupID: 307553

Reply By: cokeaddict - Wednesday, Feb 04, 2004 at 17:17

Wednesday, Feb 04, 2004 at 17:17
Hi Roachie,
Thanks for the note mate. Well I am not farmiliar with the GU setup but the same plastic plate you refer to is metal on GQ's, Well Just an update if you read about my attempts to find the heating problems in GQ's....I am oNLy refering to my GQ ok as i cant speak for other cars as everyone does different things.
But i have found some very interesting things indeed. I have NOT installed the oil cooler yet, I am very involved in finding a cure for overheating first before just ADDING things on. Starting off with dasics rather than spending dollars.

I must point out that my GQ has a 4 core radiator fitted.

First thing i did was pull out radiator and give it a good pressure clean, Also cleaned condenser while i was there, Pressure flushed cooling system and got some coolant. I replaced bottom hose with one with an internal spring as it felt a bit too soft for my liking. With all the basics done, We noticed a definate drop in general driving around temperatures ( thats heading down to Bulli).

I have run many proper tests as far as temperature goes while fully loaded and on roads of all kind of terrain, But most tests have been done on hot days. I "borrowed" a Temperature unit which had hoses and stuff running outside the body , taped to it to stop flapping...anyway i think you know what i mean. Well this thing was amazing.

SO here is what i have done so far, mind you...I am not in the "modifying " stage as i want to see any differences in temp while removing things off the car.

I found that :
by removing the Nissan Nudge bar with the 2 IPF's, temp dropped by 3 degrees (doing the same hill repeatedly) I am refering to bulli pass as its quite a test for the old girl.
The NISSAN badge sitting in the middle of the grill also restricted air flow, not much, but im trying to get this thing as cool as i can.
My next step was to remove the grill totally off the front of the car, by doing this, temp went up 2%, I thought it would drop but i now know that the actual ribs between the grill housing really work air flow towards the center of radiator. Very similar to that of a planes wing, but on a much smaller scale.

That ended the day, headed home and had more ideas already planned, I have since made up a cowl that bolts down to the car panel at front of radiator, this cover comes out moulded to the demensions of the ctr grill frame where the ribs are. It acts like a funnel, once the air hits the grill ribs, it cannot escape, so it has to pass through the radiator, We went back down to Bulli to give it 3 runs, the difference was amazing, Different day yes, but still a hot one. Anyway temp dropped by 6 degrees. Now from the Bulli climbs ive done before even thinking of these changes to the last day there, my gauge has dropped from just over 3/4 to just on 1/2.

My next try will involve adding angled fins to this cover i made up, Hoping it will swirl the air kinda like a donaldson pre filter setup. I beileve (yet to prove) that if i can get the air to swirl while under pressure it should pump more air through.

For those of you that dont understand what im trying to say here...its just like filling a bottle up with water, tuning it upside down and watching the water spill out, the air comming back in to the bottle causes the outgoing water to slow down. BUT if u were to make that water inside the bottle swirl as it comes out, you will find that it comes out much quicker and thus allowing more volume to pass in a shorter time.

Now guys, please dont dig into me on this ok, i am no scientist, its just trial and error stuff i am playing with, but so far, I have dropped the temp on my GQ to the point that i am no longer affraid of overheating. This is all taking a long time to get through and the cost of fuel etc is fairly high plus ware and tear on both me and car. But if I can do this without buying a 1200 dollar radiator and stuff, then why not if it can help others out there, I dont mind at all.

Just remember...this is MY car im refering to, I cant speak for others or what reaction they would have from this, but i drive MY car and thats all that matters to me.
I will let you know how stage 2 goes when i get round to doing it.
Regards AngeloI love it when you talk DIRTY !
AnswerID: 45449

Follow Up By: Roachie - Wednesday, Feb 04, 2004 at 17:36

Wednesday, Feb 04, 2004 at 17:36
Thanks for the comprehensive report Angelo. You sure are leaving no stone unturned in your attempts to beat the issue (note I refuse to call it a "problem"). Just another thought for you to consider.....I know a bloke in Sydney who is a tour operator; known as "DB"; Dave Bradley. He operates an arm of Vic Widman's Great Divide Tours and calls it "Platinum Tours". He is currently running a GU 4.2T/D and Ultimate Camper (same set up as me). He was featured in 4WD Monthly a few months ago.
Well before he had the GU, he had a severely worked over and loaded GQ 4.2 with Safari Intercooled Turbo. He cured his overheating problem by adding a GU bonnet scoop. He placed it centrally on the bonnet, just behind the radiator, mounted backwards. That vehicle has also been featured in 4WD MOnthly mag a year or 2 ago. If you like I can find out what issue and let you know through the forum.
Also, bear in mind that because the GQ's radiator is not as wide as the GU, the ones made by PWR might not be as expensive as the GU model; assuming they actually make a GQ replacement of course
FollowupID: 307549

Follow Up By: Mark - Wednesday, Feb 04, 2004 at 18:39

Wednesday, Feb 04, 2004 at 18:39
Hi Cokeaddict, I like your method of proving whether your changes actually work, MUCH more accurate than using the vehicle gauge and quite a scientific approach.

But I am not sure that your vortex (swirling) idea is technically correct. As an example, we had a situationat work where we had a tank of water being filled from the a pipe mounted on the side and being emptied by a pipe at the bottom in the middle (tank on a stand).

Because the feed pipe was entering on the side, the tank had a large vortex (swirling motion). This swirling motion extended down the outlet pipe in the base of the tank. The most water that we could get from the outlet pipe was 200 l/min, with the rest of the feed water overflowing the tank. I then installed a vortex breaker that stopped the swirling motion (a simple X in the bottom of the tank). All other factors remained constant. Maximum outlet flow is now over 400 l/min and the tank no longer overflows. The outlet pipe is now a solid flow of water, not swirling water with an inner air core.

As for the Donaldson example, the reason for swirling the air is to try and get any dirt flung to the outside by centrifigul force and have the dirt collected in the outer container. Note that most snorkel manufacturers do NOT recommend donalson type cleaners on turbo diesels as they restict the air flow.

I am not trying to knock your idea, but my engineering background says the theory is wrong. It may end up being a lot of effort for something that has the opposite effect. I think your funnel analogy is correct and that by simply adding sides to the grille onto the bullbar to act as a larger "mouth" will force more air into the radiator.

Look foward to hearing about your future experiments.


2003 GU 3.0TD
FollowupID: 307554

Follow Up By: Brett - Wednesday, Feb 04, 2004 at 19:49

Wednesday, Feb 04, 2004 at 19:49
I remember reading years ago thet the TOYOTA badge on the front of the early model 75 series caused a reduction in air-flow to the radiator by either 13 or 17%....amazing isn't it?
FollowupID: 307557

Reply By: cokeaddict - Wednesday, Feb 04, 2004 at 19:26

Wednesday, Feb 04, 2004 at 19:26
If you dont mind, I would be very interested in the artical. Especially the bonnet scoop, as this was one more thing i was going to try down the track, but i was considering placing it on the passengers side of bonnet at rear, just above the turbo exhaust manifold with an extended piece inside the bonnet running the air around the turbo head. But again..its only on paper at the moment.

I love it when you talk DIRTY !
AnswerID: 45458

Follow Up By: Roachie - Wednesday, Feb 04, 2004 at 20:30

Wednesday, Feb 04, 2004 at 20:30
G'day Cokeaddict,
The article about DB's GQ was in the March issue of 4WD Monthly magazine. I don't know whether you have access to the mag, so I'll quote a portion off page 43 for you.....
"..........and installed a GU bonnet scoop. However, as the Safari intercooler is mounted at the front, not atop the motor as on the current-model Patrol, the scoop faces rearwards. Its job is to exhaust hot air from the engine bay rather than feed fresh air to the intercooler; and it works- as Jameel discovered when he closed the bonnet and fired up the engine for the first time. "I hadn't put the new windscreen in yet, and I got a blast of hot air in the face!" he said"".
None of the photos shows it really clearly, but the scoop is only about 9" back from the front of the bonnet, right in the middle. I remember asking DB when I was out camping with him in the Vic High Country why he had it put there. He said it was the only place they could cut a large enough hole without cutting through a support strut. He would rather the scoop have been further back, but reckoned it worked really well in any case and was probably better off being where it was than further back after all.
As I've said before, I tried a rearward facing one over the top of my turbo, but it made no difference.
Now that I've faced it around the right way, I "think" it's working better , but bloody hard to tell as you can never duplicate the same conditions out on the road.
FollowupID: 307560

Follow Up By: Roachie - Wednesday, Feb 04, 2004 at 20:32

Wednesday, Feb 04, 2004 at 20:32
Sorry, I stuffed up (how un bloody usual, !! LOL) I forgot to add that it was March 2001 issue of 4WD Monthly.

FollowupID: 307561

Reply By: cokeaddict - Wednesday, Feb 04, 2004 at 19:30

Wednesday, Feb 04, 2004 at 19:30
Hi Mark, Thanks for you support. AS i said, I am no scientist, it was just an idea but your input was great. As i have already made the swirly bits, I will try them out soon and see if there is any difference climbing Buli pass. Worst thing is either no change OR worse. But now that you mentioned the fact that the Donaldson centrifcally tosses the dirt out to be collected by the bowl, It made me think of something else. ...Ill get back to you shortly...lolI love it when you talk DIRTY !
AnswerID: 45459

Reply By: Member - Ross - Wednesday, Feb 04, 2004 at 19:34

Wednesday, Feb 04, 2004 at 19:34
Geez guys ... I'm impressed.

All this science from a bunch of blokes I figured were smarter than a 2 bob watch ... what can I say??

Just thought I'd add my two pennies worth.

Don't get me wrong here ... only constructive input.

1. Hot water rises, or more correctly is forced up by the more dense colder water.
Accordingly the top radiator hose is usually the first to show signs of deterioration due to age/heat.

2. With regard to the swirling bit. So called laminar flow through a tube/pipe is the most efficient, where the pipe is flowing full of smooth water. The only restriction is friction against the wall of the pipe which is usually derived from a formula by a bloke by the name of Manning. Hence Manning's formula is used to establish the rate of flow through a pipe. Believe me he was ONE CLEVER DICK !!!!
Anyway ........ turbulence restricts flow.

More later ... depending on responses .............. ;-D

Fidei defensor

AnswerID: 45460

Follow Up By: cokeaddict - Wednesday, Feb 04, 2004 at 19:44

Wednesday, Feb 04, 2004 at 19:44
Hey Rosco,
Thanks for that mate, very well timed indeed. Excellent input. Seems like the more i read, the more ideas i get, Well just for the record..I will lick this thing..and NO im not refering to the missus :-)

I love my GQ and i just cant stand to see that gauge rise when im enjoying the feel of that turbo come in when i start climbing hills. I have some time to spare.I love it when you talk DIRTY !
FollowupID: 307556

Follow Up By: Member - Ross - Wednesday, Feb 04, 2004 at 22:59

Wednesday, Feb 04, 2004 at 22:59

Not only the boost ..... which let's face it .... ain't nearly as exciting as the boot from a big 6/8 petrol job.

But hey ... if you're on the board you can almost whistle a tune with the turbo whine.

Sh1tloads of fun ..............;-))))))))))))))))Fidei defensor

FollowupID: 307582

Follow Up By: Member - Ross - Wednesday, Feb 04, 2004 at 23:25

Wednesday, Feb 04, 2004 at 23:25

One more thing occurred to me on re-reading your response.

I noted in a scientific journal recently that Italians were known to have a problem with their bottom hoses being soft and squishy to the touch when hot and sqeezed.

Do ya reckon if ya left it alone for a while it might stiffen up on its own accord ?

Not casting any Nasturschums about/at your name .......... (read aspersions).

Just a thought cobber

Fidei defensor

FollowupID: 307585

Reply By: cokeaddict - Thursday, Feb 05, 2004 at 00:41

Thursday, Feb 05, 2004 at 00:41
I will let you in on a huge Italian secret old mate, What you read was correct as far as MANY Italian "studs" are concerned. Just look at Silvester Stallone.."the Italian Stallion" as he is known, Fact is they should have nicked named him "Jelly Bean", Especially after what some women have said about his enormous ego.

Thank god i was born here !!!!!I love it when you talk DIRTY !
AnswerID: 45512

Reply By: Member - Wim (Bris) - Thursday, Feb 05, 2004 at 08:39

Thursday, Feb 05, 2004 at 08:39

The future looks bright is this thread is any gauge of ozi ingenuity.

A thought on your air flow problem. It is posible to increase the airflow to much. Too higher velocity will reduce the cooling effect of the radiator.
As previously mentioned, laminar flow is the way to go.
PS. I notice no number 8 fencing wire has been used yet :-)

All the best and keep us all posted.This 4WD stuff is addictive,
time consuming & expensive.
AnswerID: 45529

Reply By: Jon - '88 TD42 GQ - Thursday, Feb 05, 2004 at 12:50

Thursday, Feb 05, 2004 at 12:50
My only comment re: the swirling air discussion is that you have to consider the difference between a system where air/water is passing through an aperture (ie the radiator) and a situation where the air/water is exiting a container through an apeture (ie water out of a bottle). In the latter case you have to have water out and air in regardless, the swirl makes this work better becasue it creates a tunnel for the air. The better anology for your rad would be a hose, where the water enters one end and exits the other and nothing comes the other way, in which case a swirl doesn't help. Just food for though.

Re: the bonnet scoops, and interesting GQ is here discussed here: this thing is getting 185kW out of a TD42 and notes:

"The addition of bonnet grills was necessary so as to reduce under bonnet temperatures. The temperatures where reaching such levels that the vent air for the cabin was being preheated to very high temperatures and also resulted in extensive heating of the fire wall. After fitting the grills the under bonnet temperatures have fallen drastically and has also assisted in increasing air flow through the engine bay and cooling system."

He has an image of the vents he used. Has them on both side of the bonnet and are an actual vent rather than a scoop.

Again, just food for thought.

Personally I haventt got to concerned about the heat issue. I hit about 2/3 at most on climbs but never more and it never overheats - just gets hotter under load. I just had my cooling system flushed at the last service and it was apparently full of crap so it will be interesting to see how it goes on the next big hill. I also plan on pulling out the rad and giving it a good clean as this seems likely to help, especially after the mud I sprayed over the thing a few weeks back!


AnswerID: 45539

Follow Up By: Jon - '88 TD42 GQ - Thursday, Feb 05, 2004 at 12:52

Thursday, Feb 05, 2004 at 12:52
I should have also mentioend that I've been following your experiments with interest. It's nice to see some objective experiments rather than the old "I whacked on a fat exhaust and it felt 20kW better!" type talk we all go on with.

FollowupID: 307613

Reply By: Truckster (Vic) - Thursday, Feb 05, 2004 at 21:50

Thursday, Feb 05, 2004 at 21:50
Noting that 99% of GQs with overheating issues have Turbos, and many of them have the Denco system, which I think is the main problem.

the location of the Turbo, the angles of the pipes coming out of it, etc....

The things rarely overheat prior to the snail going on....
AnswerID: 45613

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