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cas-gord
29th December 2010, 04:20 PM
We have 2002 gu 4.2 turbo diesel, overheats when going up big hill towing 3 ton caravan been doing it since new, would an intercooler or oil cooler solve problem?

patch697
29th December 2010, 05:33 PM
Both will help but not necessarily fix it.

One of our Moderators on here is a mechanical GURU. He may have some good advice for you here.

YNOT
29th December 2010, 09:42 PM
The fact that the car has been struggling to keep it's cool since new indicates that there is probably not actually a fault with the car, just that towing a 3 tonne van up a big hill puts a massive strain on the cooling system. You probably figured that out already!

What to do about it?

First you need to maximize the airflow through the radiator. If you have big spotlights either remove them or fit smaller lights. Make sure the radiator is sealed around the edges with foam tape so that all the air entering the front of the car is forced through the radiator. If you have a fly screen type bug screen across the front of the car, remove it. Regularly check the radiator and A/C condensor fins for debris build up.
You should probably also consider fitting an upgraded aluminium intercooler like the ones PWR sell. (www.pwr.com.au)

Next is engine tuning. You can go two ways here, either get it dyno tuned to ensure pump timing, boost and fuel delivery are properly set to factory settings, or go for a higher state of tune. Obvoiusly this option will cost a bit more. There are several companies (MTQ turbo's is one) that can rebuild your turbo with larger compressor and turbine wheels which are a lot more efficient and will result in a much cooler air charge at the same or higher boost levels. Combine the high flow turbo with a bigger exhaust (including the dump pipe off the back of the turbo, very important) and a full dyno tune and the engine will have a lot more power and torque (up to about 30% more) meaning you won't need to work the car as hard to get that big van up the hills.

Intercooling will help as well, but look for a well designed top mount intercooler and a large scoop. I suggest top mount over front mount as a front mount will add more heat to the air entering the radiator as well as adding a restriction to the air flow. Check www.are.com.au, those guys know more than most about the subject and have done a fair bit of research into scoop design as well.

An oil cooler may help a little as well, but finding a location where it does not interfere with radiator air flow might be a challenge.

Tony

AB
30th December 2010, 07:46 PM
I'll move this thread here mate so others can see it better.

MQ MAD
31st December 2010, 09:18 AM
So youve had the car since new and your persurveering with a heating problem this long ???
This problem should have been fixed long ago,seen the price to repair these motors
Anyway the usual problems with heating issues is blocked radiators youll be surprised what the impact of this will do
After owning this long ,it would be something near first to do
Get the radiator rodded,about $100 ish (you remove and replace)
Then go from there
My GQ (under 200K when bought) had a heating issue within 2 weeks of purchase
It was a blocked radiator
Your car being 8 year old there would no doubt be a few things in the cooling system that would need replacing by now
Hows the clutch fan hub,plastic fan have any cracks ect ect

gibbon
3rd January 2011, 10:26 AM
mate i put a tefba filter in its a i line filter for top radiator hose(there on line) n it picked up heaps of shit n my temp came down a bit
they r gold put em on all my cars now

Macgyver
12th January 2011, 08:36 AM
My sons GQ 1991 Gq Patrol overheats on the highway about an Hour after running at 2200 rpm. Checked everything including head, new radiator, thermostat, radiator cap, water pump. Just found a vacuum leak near the carby hope this fixes it. It is dual fuel LPG/Petrol and overheats on both. Just keeps pumping out coolant into overflow bottle and then boiling. Weird one!!!

Bigrig
12th January 2011, 08:51 AM
My sons GQ 1991 Gq Patrol overheats on the highway about an Hour after running at 2200 rpm. Checked everything including head, new radiator, thermostat, radiator cap, water pump. Just found a vacuum leak near the carby hope this fixes it. It is dual fuel LPG/Petrol and overheats on both. Just keeps pumping out coolant into overflow bottle and then boiling. Weird one!!!

Just replaced the radiator in my 92 GQ to an all alloy unit - overheated at the slighest of hills and pretty much ran (highway driving) at about two thirds on the indicator - new radiator, cooling system flush, and colder thermostat then SHAZAM!!! Runs at about one third on the indicator, doesn't have any bother with hills etc, and I have the Nissan badge and 4 spotties lined up in front of it ... it still heats up a bit if pushing it out on the tracks, and especially on LPG (runs hotter anyway I believe) but other than this, I am still looking into (help Tony!!!!) getting an intercooler for the gearbox as it just seems to run blistering hot (auto, but I can feel the heat off the console in the car to the point it burns my leg!!)

YNOT
12th January 2011, 02:54 PM
Scott, there is too much air getting to your radiator, you should fit a high mount winch up the front to block some more air flow!

Intercoolers are for cooling air heated by turbo or superchargers, you need an oil cooler to cool oil!

Tony

Sir Roofy
12th January 2011, 03:31 PM
maybe the cooler is to small for the auto or you got no
oil in the trans

roofy

YNOT
12th January 2011, 03:41 PM
My sons GQ 1991 Gq Patrol overheats on the highway about an Hour after running at 2200 rpm. Checked everything including head, new radiator, thermostat, radiator cap, water pump. Just found a vacuum leak near the carby hope this fixes it. It is dual fuel LPG/Petrol and overheats on both. Just keeps pumping out coolant into overflow bottle and then boiling. Weird one!!!

I'll give this one a bit more thought and get back to you, you've already replaced all the parts I would normally suggest. How much gear is there in front of the radiator, winches, spot lights etc?

Tony

Macgyver
18th January 2011, 12:04 PM
Just pulled the head off the GQ and found a weeping head gasket between number 6 cylinder and the water gallery. Weird though because I tested the radiator coolant for exhaust gases and there was none found. Lucky for me I have a Rottler F65A cnc cylinder boring machine and head surfacer at work. So I quickly pulled down the head, measured up the cylinder height, found it to be stock std,machined the deck by 40 thou to allow for LPG, lapped in the valves, reassembly ready for tonight.... Will wack some pictures on soon....

Plasnart
18th January 2011, 12:17 PM
So I quickly pulled down the head, measured up the cylinder height, found it to be stock std,machined the deck by 40 thou to allow for LPG, lapped in the valves, reassembly ready for tonight.... Will wack some pictures on soon....

Haha, sounds like Macgyver all right! Except he would have done all that in a coconut plantation!!

Adlarplant
25th January 2011, 12:34 AM
just going through the dramas of a second hand td42t overheating in my my02 cab chassis just another case of me spending dollars to save cents.Heres what ive done to fix the prob. Changed coolant sensor to one that was on td42 engine sensors may be incompatible-still running hot.rod radiator and back flush block-still running hot (110c on 28c day no load on vehicle measured with murphy master gauge) changed water pump,thermostat fan hub belts and hoses-still running hot (radiator is 4 core staggered core type) Backed off boost and turned back fuel pump-still running hot.Changed all filters-still running hot,CO2 tested engine-dye turned yellow rang supplier and told of dramas and took down to Brisbane they tested coolant and found CO2 present and said it was nothing to worry about and placed a bottle of block seal into radiator and said this stuff will fix it (after 25 years as a diesel mechanic ive never seen them work as a long term fix) what do u know it was still running hot.
Rang supplier and using one syllable words explained it was worse they came to the party with a new head gasket was told hand on heart it was all fixed .Maiden voyage home running hot at Willsonton at the bottom of the range,pulled over let it cool checked all fluid levels all good i climbed the range no problem cool as a cucumber 20 mins later running hot again this went on to Pampas ran for 20 mins ok then running hotbut now blowing blue smoke as well,shut it down checked everything restarted and all good then i noticed when they refitted the pcv hose to airfilter (im running an after market turbo with the rectangular filter assembly) they had kinked the hose therefore i was pressurizing the sump and the turbo couldnt drain so it was running like it had a engine brake on permanently cut the hose vented to atmosphere blocked out let under air clenaer and i thought it was cured.
Drove it round over xmas all good then took it over to Esperence got to Yunta and up goes the temp gauge again nursed it into Pt Augusta drained te coolant and refilled with water and a bottle of the suppliers miracle goop and launched it westwood it held in there for the trip over and most of the way back last 250 kms at 60km hr.
Time for me to go back to my trade time .Removed the head and noticed head studs not overly tight and head gasket laying loose on the block,checked head gasket and found no signs of compression and 8 bolts shiny at bottom where they had bottomed out.Rang my fave parts people at Dalby ordered a new head,exhaust valves, gaskets etc Got my machinst to make the new head ready then for the fun part
Re-tapped all the head bolts wat dirtier than id expected with the head off 15000km ago then out of curiosity i checked the water galleries around the cylinder liners (old habits die hard) and found them totally filled with many years of built up gunge sealants and what ever else had been put into the engine. With drills files compressed air and patience i cleaned the galleries Fitted the new head.
Just took it down to Narrabri and back for a test drive and no more over heating .I know ive rambled on here hell i even fitted a trans cooler with an electric fan under the tray to suplement the radiator,but what im really saying is the temp can be gotton under control and watch waht u put into the radiator it WILL come back to haubt you Cheers Adam

GQshorty
18th February 2012, 06:03 PM
thanks guys info helped alot.